MFDS Part 1 Exam — Questions and Answers

Question 1: A 52-year-old female patient complains of a persistently dry mouth and dry eyes for over six months. Clinical examination reveals a high caries rate and a lobulated tongue. Which investigation is most specific for confirming a diagnosis of primary Sjögren's syndrome?

A full blood count to check for anaemia.
Measurement of unstimulated whole salivary flow rate.
Parotid sialography to assess ductal architecture.
Serological testing for anti-Ro (SSA) and anti-La (SSB) autoantibodies. (Correct answer)

Correct answer: Serological testing for anti-Ro (SSA) and anti-La (SSB) autoantibodies.

While reduced salivary flow confirms hyposalivation, and other tests may show non-specific changes, the presence of specific autoantibodies, particularly anti-Ro (SSA) and/or anti-La (SSB), is a key diagnostic criterion for Sjögren's syndrome according to UK and international guidelines. These serological markers point towards the underlying autoimmune nature of the disease.

Question 2: Adrenaline (epinephrine) is added to local anaesthetic solutions primarily to:

Reduce systemic toxicity alone
Alkalinise the solution
Cause vasoconstriction and prolong anaesthesia (Correct answer)
Increase patient alertness

Correct answer: Cause vasoconstriction and prolong anaesthesia

Adrenaline causes local vasoconstriction, reducing vascular uptake and thus prolonging the duration and depth of anaesthesia while reducing systemic absorption.

Question 3: The maxillary teeth receive their primary arterial supply from branches of which artery?

Infraorbital artery
Maxillary artery (Correct answer)
Facial artery
Buccal artery

Correct answer: Maxillary artery

The posterior superior alveolar and anterior superior alveolar arteries, both branches of the maxillary artery, supply the maxillary teeth and their supporting structures.

Question 4: In caries risk assessment, which factor contributes most significantly to high caries risk categorisation?

Well-controlled type 2 diabetes
Use of fluoride toothpaste
Age over 40
Presence of active white spot lesions and high sucrose intake (Correct answer)

Correct answer: Presence of active white spot lesions and high sucrose intake

Active demineralisation (white spot lesions) combined with frequent fermentable carbohydrate intake indicates current disease activity and high future caries risk.

Question 5: The posterior superior alveolar nerve typically supplies which maxillary molar roots?

Only the second and third molars entirely
All roots of the first and second molars
All roots of all three maxillary molars
All roots of the second and third molars, and the distobuccal and palatal roots of the first molar (Correct answer)

Correct answer: All roots of the second and third molars, and the distobuccal and palatal roots of the first molar

The posterior superior alveolar nerve typically supplies the maxillary second and third molars in their entirety and the distobuccal and palatal roots of the first molar; the mesiobuccal root of the first molar is usually supplied by the middle superior alveolar nerve.

Question 6: The polymerisation shrinkage of conventional composite resins is approximately:

10–15%
1–3% (Correct answer)
5–8%
0.1–0.5%

Correct answer: 1–3%

Conventional methacrylate-based composites shrink by approximately 1–3% by volume during polymerisation as monomers convert to a polymer network.

Question 7: A dental hygienist is working under 'Direct Access' arrangements. A new patient attends requesting treatment. According to the GDC's 'Scope of Practice' and relevant UK legislation, which of the following procedures requires a prescription from a dentist before the hygienist can proceed?

Providing tooth whitening treatment using a 6% hydrogen peroxide gel. (Correct answer)
Taking bitewing radiographs to check periodontal bone levels.
Undertaking a routine scale and polish.
Applying a topical fluoride varnish.

Correct answer: Providing tooth whitening treatment using a 6% hydrogen peroxide gel.

While 'Direct Access' allows dental hygienists to perform much of their scope of practice without a dentist's prescription, tooth whitening is a specific legal exception. [6, 11] The Cosmetic Products Enforcement Regulations 2013 stipulate that products containing or releasing between 0.1% and 6% hydrogen peroxide can only be used on the prescription of a dentist after a clinical examination. [6, 13] The first use of a cycle must also be carried out by a dentist or under their direct supervision. [6, 11]

Question 8: Thrombocytopenia significant for dental practice (increased bleeding risk) is generally considered when platelets fall below:

50 × 10⁹/L (Correct answer)
150 × 10⁹/L
80 × 10⁹/L
10 × 10⁹/L

Correct answer: 50 × 10⁹/L

A platelet count below 50 × 10⁹/L is associated with significantly increased bleeding risk for invasive dental procedures; haematology consultation is advised below this threshold.

Question 9: Which type of tooth movement is most energy-efficient and causes the least root resorption in orthodontics?

Bodily movement
Extrusion
Tipping (Correct answer)
Torque

Correct answer: Tipping

Tipping (crown movement with fulcrum at the apical third) requires the least force and produces less root resorption than bodily movement, though it produces less controlled movement.

Question 10: In Angle's classification, a Class II division 2 malocclusion is characterised by:

Retroclined upper central incisors and a deep overbite (Correct answer)
Proclined upper central incisors
Upper arch narrow with crowding
Anterior crossbite

Correct answer: Retroclined upper central incisors and a deep overbite

Class II division 2 features a Class II skeletal relationship with retroclined upper central incisors (and sometimes proclined laterals), typically producing a deep overbite.

Question 11: What are the characteristic features of Behçet's disease and which diagnostic criteria are used?

Unilateral facial swelling and trismus; diagnosed by CT imaging
Recurrent parotid gland swelling and xerostomia; diagnosed by Sjögren's criteria
White mucosal patches and dysphagia; diagnosed by biopsy
Recurrent oral ulceration plus at least two of: recurrent genital ulceration, eye lesions, skin lesions, or positive pathergy test; diagnosed by International Study Group criteria (Correct answer)

Correct answer: Recurrent oral ulceration plus at least two of: recurrent genital ulceration, eye lesions, skin lesions, or positive pathergy test; diagnosed by International Study Group criteria

Behçet's disease is a chronic multisystem vasculitis. The International Study Group criteria require recurrent oral ulceration (at least 3 episodes in 12 months) plus two of: recurrent genital ulceration, eye lesions (anterior/posterior uveitis, retinal vasculitis), skin lesions (erythema nodosum, pseudofolliculitis, papulopustular lesions), or a positive pathergy test (skin hyperreactivity to needle prick). It is most prevalent along the ancient Silk Road (Turkey, Iran, Japan).

Question 12: At which anatomical point does the facial artery cross the inferior border of the mandible?

At the antegonial notch, just anterior to the masseter (Correct answer)
At the mental foramen
At the angle of the mandible
At the midpoint of the mandibular body

Correct answer: At the antegonial notch, just anterior to the masseter

The facial artery hooks around the inferior border of the mandible at the antegonial notch, immediately anterior to the anterior border of the masseter, where the pulse can be palpated and haemorrhage can be controlled by compression.

Question 13: A 3-year-old child presents after a fall, having intruded their maxillary primary central incisor (51). Clinically, the tooth is barely visible. A radiograph confirms the apex has been displaced buccally, away from the developing permanent tooth germ. According to the International Association of Dental Traumatology (IADT) guidelines followed in the UK, what is the most appropriate management?

Surgical repositioning and splinting of the tooth.
Advise the parent to monitor for spontaneous re-eruption. (Correct answer)
Immediate extraction to prevent damage to the permanent tooth.
Prescription of systemic antibiotics and active surveillance.

Correct answer: Advise the parent to monitor for spontaneous re-eruption.

For an intruded primary tooth, especially when the apex is displaced buccally (away from the permanent successor), the standard of care is to allow for spontaneous re-eruption. This typically occurs over several months. Active intervention like surgical repositioning or extraction is generally avoided unless there is evidence of infection or the apex is impinging on the permanent tooth germ, as these interventions carry their own risk of iatrogenic damage to the successor.

Question 14: Taste sensation from the anterior two-thirds of the tongue is conveyed by which nerve?

Glossopharyngeal nerve (CN IX)
Greater petrosal nerve (CN VII)
Lingual nerve (CN V3)
Chorda tympani (CN VII) (Correct answer)

Correct answer: Chorda tympani (CN VII)

The chorda tympani, a branch of the facial nerve (CN VII), carries special visceral afferent (taste) fibres from the anterior two-thirds of the tongue and travels with the lingual nerve in the infratemporal fossa.

Question 15: Which instrument design is most appropriate for initial negotiation of a calcified or curved root canal?

ISO size 10 stainless steel K-file (Correct answer)
ISO size 25 K-file
Rotary NiTi file size 25/0.06
ISO size 40 Hedstroem file

Correct answer: ISO size 10 stainless steel K-file

A size 10 stainless steel K-file is small, flexible and appropriate for initial exploration of calcified or curved canals where larger instruments risk ledging or transportation.

Question 16: What quality assurance measures should be routinely performed on dental X-ray equipment in the UK?

No quality assurance is required for dental X-ray equipment
Only annual servicing by the manufacturer is required
Regular testing of tube output, timer accuracy, beam alignment, film processing (if applicable), image quality using test objects, and maintaining QA records as required by IRR17 and IRMER 2017 (Correct answer)
Quality checks are only needed when the equipment is new

Correct answer: Regular testing of tube output, timer accuracy, beam alignment, film processing (if applicable), image quality using test objects, and maintaining QA records as required by IRR17 and IRMER 2017

UK regulations (IRR17 and IRMER 2017) require a written quality assurance programme including: acceptance testing of new equipment, regular testing of tube output consistency and kV accuracy, timer accuracy, beam alignment and collimation, film processor monitoring (sensitometric strips if using film), digital sensor/phosphor plate checks, image quality assessment using test objects, reject/retake analysis to identify systematic problems, and record keeping of all QA activities. Critical examination must be performed before first use, and routine QA testing should be carried out at intervals recommended by the radiation protection adviser.

Question 17: A patient undergoing treatment for Stage III periodontitis has generalised gingival recession, resulting in large, open interdental spaces. According to UK guidance, such as 'Delivering Better Oral Health', what is the most effective and recommended tool for daily interdental plaque removal in these areas?

Rubber-tipped stimulators
Interdental brushes (Correct answer)
An oral irrigator
Dental floss

Correct answer: Interdental brushes

For patients with periodontitis who have open interdental spaces, interdental brushes are consistently shown to be more effective at removing plaque than dental floss. UK guidelines, including those from the BSP and Public Health England's 'Delivering Better Oral Health', recommend interdental brushes as the first choice for these patients, with the size of the brush being matched to the space.

Question 18: A diabetic patient taking metformin presents for dental treatment. Their HbA1c is 75 mmol/mol (9.0%). What is the clinical significance of this result?

The result is within the pre-diabetic range and has no relevance to dental treatment
The diabetes is poorly controlled (target <48 mmol/mol), indicating increased risk of delayed healing, infection, and the need for medical liaison before elective surgical procedures (Correct answer)
The diabetes is well controlled and routine treatment can proceed without concern
The HbA1c indicates hypoglycaemia risk only

Correct answer: The diabetes is poorly controlled (target <48 mmol/mol), indicating increased risk of delayed healing, infection, and the need for medical liaison before elective surgical procedures

An HbA1c of 75 mmol/mol (9.0%) indicates poor glycaemic control. The NICE target for type 2 diabetes is generally 48 mmol/mol (6.5%) or 53 mmol/mol (7.0%). Poor control increases the risk of impaired wound healing, susceptibility to infection (including periodontal disease progression), dry mouth, candidiasis, and delayed recovery from surgical procedures. Medical liaison is advisable before elective invasive dental treatment.

Question 19: A patient suddenly loses consciousness in the dental chair and begins a tonic-clonic seizure. Which of the following actions is the most important immediate priority for the dental team?

Note the time the seizure started and protect the patient from injury. (Correct answer)
Immediately administer buccal midazolam.
Insert a bite block or prop between the teeth to protect the tongue.
Attempt to restrain the patient's convulsive movements.

Correct answer: Note the time the seizure started and protect the patient from injury.

The primary management during a convulsive seizure is to prevent injury. The dental team should protect the patient from hitting hard surfaces and note the time of onset to determine if it becomes prolonged. Nothing should be placed in the patient's mouth, as this can cause dental trauma or obstruct the airway. Restraining movements is ineffective and can cause injury. Midazolam is only indicated if the seizure is prolonged (typically lasting 5 minutes or more) or repeats rapidly.

Question 20: Which nerve is most commonly damaged during a sagittal split osteotomy of the mandible, and what are the typical symptoms?

The lingual nerve, causing loss of taste on the anterior two-thirds of the tongue
The inferior alveolar nerve, causing altered sensation (numbness or paraesthesia) of the lower lip, chin, and teeth on the affected side (Correct answer)
The facial nerve, causing motor paralysis of the lower lip
The hypoglossal nerve, causing deviation of the tongue

Correct answer: The inferior alveolar nerve, causing altered sensation (numbness or paraesthesia) of the lower lip, chin, and teeth on the affected side

The inferior alveolar nerve is at greatest risk during bilateral sagittal split osteotomy (BSSO) because the osteotomy cuts pass in close proximity to, or directly over, the nerve canal within the mandibular body. Damage results in altered sensation (hypoaesthesia, paraesthesia, or anaesthesia) of the lower lip, chin, and mandibular teeth. The incidence of temporary IAN disturbance ranges from 30-85%, with permanent damage in approximately 3-5% of cases.

Question 21: A dental nurse posts a photograph on their private, personal social media account. In the background, a patient's unique and identifiable tattoo is visible on their arm, although their face is not shown. A colleague recognises the tattoo and identifies the patient. Which principle from the General Dental Council's (GDC) 'Standards for the Dental Team' has primarily been breached?

Principle 6: Work with colleagues in a way that is in patients' best interests.
Principle 8: Raise concerns if patients are at risk.
Principle 2: Communicate effectively with patients.
Principle 4: Maintain and protect patients' information. (Correct answer)

Correct answer: Principle 4: Maintain and protect patients' information.

GDC Standard 4.2.3 explicitly states: 'You must not post any information or comments about patients on social networking or blogging sites.' [8] Even if unintentional, on a private account, and without showing a face, posting an image from which a patient can be identified (in this case by a unique tattoo) is a breach of the duty to protect patient confidentiality. [14, 33, 36] The standards of professional conduct apply in both online and offline environments. [8, 14]

Question 22: What are the histological features that distinguish an odontogenic keratocyst (OKC) from other odontogenic cysts?

Mucous-secreting epithelium with goblet cells
Thick, non-keratinised epithelial lining with rete ridges
Thin, regular parakeratinised stratified squamous epithelium (5-8 cells thick) with a corrugated surface, prominent basal layer with palisading, and absence of rete ridges (Correct answer)
Ciliated columnar epithelium resembling respiratory mucosa

Correct answer: Thin, regular parakeratinised stratified squamous epithelium (5-8 cells thick) with a corrugated surface, prominent basal layer with palisading, and absence of rete ridges

The OKC (now reclassified as odontogenic keratocyst in the 2017 WHO classification, reverting from 'keratocystic odontogenic tumour') has distinctive histology: a thin, regular parakeratinised stratified squamous epithelium typically 5-8 cells thick with a corrugated (wavy) surface, a well-defined palisaded basal layer of cuboidal or columnar cells, and characteristically lacks rete ridge formation. The lumen contains desquamated keratin. These features, along with its high recurrence rate, distinguish it from other odontogenic cysts.

Question 23: Which systemic condition is most commonly associated with erythema multiforme?

Herpes simplex virus infection (Correct answer)
Systemic lupus erythematosus
HIV infection
Crohn's disease

Correct answer: Herpes simplex virus infection

The most common precipitant of recurrent erythema multiforme is herpes simplex virus (HSV) infection, which triggers an immune-mediated reaction.

Question 24: The principal fibres of the periodontal ligament that run obliquely and are most numerous are the:

Apical fibres
Horizontal fibres
Alveolar crest fibres
Oblique fibres (Correct answer)

Correct answer: Oblique fibres

Oblique fibres are the most numerous principal fibre group of the periodontal ligament, running from cementum to alveolar bone to resist axial forces.

Question 25: What is the maximum recommended dose (MRD) of 2% lidocaine with 1:80,000 adrenaline for a healthy 70 kg adult, according to the British National Formulary (BNF)?

4.4 mg/kg
2.2 mg/kg
7.0 mg/kg (Correct answer)
10.0 mg/kg

Correct answer: 7.0 mg/kg

The British National Formulary (BNF) and other authoritative sources state the maximum recommended dose of lidocaine with adrenaline for dental use is 7.0 mg/kg of body weight, with an absolute maximum not to exceed 500 mg. The dose of 4.4 mg/kg is the maximum for lidocaine without a vasoconstrictor.

Question 26: Which muscle forms the muscular floor ('diaphragm') of the oral cavity?

Anterior belly of digastric
Geniohyoid
Mylohyoid (Correct answer)
Stylohyoid

Correct answer: Mylohyoid

The paired mylohyoid muscles, meeting at a midline raphe and attached to the mylohyoid line of the mandible and the hyoid bone, form the muscular floor of the mouth.

Question 27: A patient undergoing conscious sedation with intravenous midazolam becomes over-sedated and experiences significant respiratory depression. According to UK sedation guidelines (IACSD), which drug is the specific reversal agent for this situation?

Adrenaline
Atropine
Naloxone
Flumazenil (Correct answer)

Correct answer: Flumazenil

Flumazenil is a specific benzodiazepine receptor antagonist and is the correct agent to reverse the sedative and respiratory depressant effects of midazolam. Naloxone is an opioid antagonist, Adrenaline is used for anaphylaxis, and Atropine is used to manage bradycardia.

Question 28: What radiographic features would suggest a lesion in the jaw is malignant rather than benign?

Ill-defined, irregular, ragged margins with no corticated border, destruction of adjacent structures (teeth, cortical bone, inferior alveolar canal), and a 'moth-eaten' or permeative pattern of bone destruction (Correct answer)
Well-defined margins with a corticated border
A perfectly round radiolucent area with a sclerotic rim
A mixed radiolucent-radiopaque lesion with a clear capsule

Correct answer: Ill-defined, irregular, ragged margins with no corticated border, destruction of adjacent structures (teeth, cortical bone, inferior alveolar canal), and a 'moth-eaten' or permeative pattern of bone destruction

Malignant lesions typically show: ill-defined, irregular, non-corticated margins (indicating aggressive, uncontrolled growth); ragged or 'moth-eaten' pattern of bone destruction; destruction of adjacent anatomical structures (resorption of tooth roots, erosion of the inferior alveolar canal wall, destruction of cortical bone); 'floating teeth' (teeth appearing to hang in space due to extensive bone loss); sunburst or onion-skin periosteal reaction (in osteosarcoma); and soft tissue mass. In contrast, benign lesions typically have well-defined, corticated margins.

Question 29: Dead tracts in dentine are caused by:

Secondary caries
Pulp necrosis
Sclerosis of tubules
Degeneration of odontoblast processes (Correct answer)

Correct answer: Degeneration of odontoblast processes

Dead tracts result from the death and retraction of odontoblast processes, leaving empty tubules that appear dark in ground sections.

Question 30: When carrying out a direct pulp cap, which material is currently considered the gold standard?

Mineral trioxide aggregate (MTA) (Correct answer)
Calcium hydroxide
Glass ionomer cement
Zinc oxide eugenol

Correct answer: Mineral trioxide aggregate (MTA)

MTA has become the gold-standard pulp-capping material due to its superior biocompatibility, sealing ability and consistent promotion of tertiary dentine bridge formation compared to calcium hydroxide.

Question 31: What property of impression materials describes their ability to recover from deformation after removal from the mouth?

Viscosity
Elastic recovery (Correct answer)
Wettability
Dimensional stability

Correct answer: Elastic recovery

Elastic recovery (or strain recovery) is the ability of an impression material to return to its original dimensions after being deformed during removal from undercuts.

Question 32: A new 8-year-old patient attends for an initial examination. Clinically, they have a mixed dentition with closed posterior contacts and no evidence of caries. According to the Faculty of General Dental Practice (UK) 'Selection Criteria for Dental Radiography', what is the most appropriate radiographic investigation for caries diagnosis at this visit?

Bilateral posterior bitewing radiographs. (Correct answer)
No radiographs are indicated at this visit.
Periapical radiographs of all posterior teeth.
A panoramic radiograph (OPT/OPG).

Correct answer: Bilateral posterior bitewing radiographs.

The FGDP(UK) 'Selection Criteria for Dental Radiography' recommends that for a new child patient in the mixed dentition, if posterior contacts are closed (preventing visual and tactile inspection), posterior bitewing radiographs are indicated to assess for proximal caries, irrespective of the apparent clinical absence of disease.

Question 33: When raising a full-thickness mucoperiosteal flap for the surgical removal of an impacted mandibular third molar, which technical principle is most crucial for preventing iatrogenic injury to the lingual nerve?

Placing the initial incision deep in the lingual sulcus to be away from the surgical field.
Using a broad, flat retractor to actively pull the lingual tissues away from the mandible.
Making a large distal relieving incision that extends towards the buccal aspect.
Keeping the periosteal elevator in constant, firm contact with the lingual plate of bone during elevation. (Correct answer)

Correct answer: Keeping the periosteal elevator in constant, firm contact with the lingual plate of bone during elevation.

The lingual nerve has a variable course but often lies in very close proximity to the lingual cortical plate, sometimes within the periosteum. The safest technique is to keep the elevator firmly on the bone surface, elevating the entire mucoperiosteum (including the nerve) as a single, intact unit. This protects the nerve from being torn or crushed. Placing retractors blindly or making incisions directly into the lingual soft tissues significantly increases the risk of direct nerve trauma.

Question 34: A dentist is completing the clinical records after an examination. According to the Faculty of General Dental Practice (UK) 'Clinical Examination and Record-Keeping' guidelines, which classification system should be used to describe recommendations?

A (Aspirational), B (Basic), C (Conditional) (Correct answer)
Grade I, Grade II, Grade III Evidence
Urgent, Necessary, Elective
High, Medium, Low Priority

Correct answer: A (Aspirational), B (Basic), C (Conditional)

The FGDP(UK) guidelines 'Clinical Examination and Record-Keeping' categorise recommendations as A (Aspirational - gold-standard practice), B (Basic - essential/baseline practice), and C (Conditional - dependent upon circumstances). This system provides clarity on the expected standards of care and record-keeping.

Question 35: Fluconazole is the drug of choice for treating which oral fungal infection?

Mucormycosis
Cryptococcosis
Aspergillosis
Oropharyngeal candidiasis (Correct answer)

Correct answer: Oropharyngeal candidiasis

Fluconazole, a triazole antifungal, is highly effective and well tolerated for oropharyngeal and oesophageal candidiasis, particularly in immunocompromised patients.

Question 36: What is the maximum recommended dose of radiation for occupational exposure per year for dental professionals in the UK, according to the Ionising Radiations Regulations 2017 (IRR17)?

100 mSv per year
20 mSv per year (whole body effective dose limit for classified workers) (Correct answer)
1 mSv per year
50 mSv per year

Correct answer: 20 mSv per year (whole body effective dose limit for classified workers)

Under the Ionising Radiations Regulations 2017 (IRR17), the dose limit for occupational exposure for classified radiation workers is 20 mSv effective dose per year (averaged over 5 years, with no single year exceeding 50 mSv). For non-classified workers (which includes most dental professionals), the practical limit is lower. The dose limit for the general public is 1 mSv per year. In a well-run dental practice, staff doses should be negligible (<0.1 mSv/year) due to appropriate shielding, distance, and time protocols.

Question 37: Which drug is used prophylactically to prevent infective endocarditis before high-risk dental procedures?

Metronidazole 400mg pre-operatively
Clindamycin 600mg IV during procedure
Amoxicillin 3g orally 1 hour before
NICE guidelines no longer recommend routine antibiotic prophylaxis (Correct answer)

Correct answer: NICE guidelines no longer recommend routine antibiotic prophylaxis

NICE guideline CG64 (2008, maintained in reviews) concludes there is insufficient evidence that antibiotic prophylaxis prevents IE and recommends against routine prophylaxis for dental procedures.

Question 38: What is the primary function of the stratum intermedium in the developing tooth?

Formation of root sheath
Support of ameloblast function (Correct answer)
Secretion of enamel matrix proteins
Production of dentine

Correct answer: Support of ameloblast function

The stratum intermedium is thought to support the metabolic activity of the inner enamel epithelium (ameloblasts) via enzyme activity and gap junction communication.

Question 39: What does the term 'thixotropic' mean when applied to impression materials?

Sets faster when heated
Releases hydrogen gas on setting
Has permanent deformation on removal
Becomes less viscous under shear stress (Correct answer)

Correct answer: Becomes less viscous under shear stress

Thixotropic materials decrease in viscosity when subjected to shear stress (e.g. mixing or syringing) and return to a gel-like state at rest, aiding injection and flow.

Question 40: What is the ALARA (or ALARP) principle in dental radiology and how is it applied in practice?

As Low As Reasonably Achievable (or Practicable) — radiation doses should be kept to the minimum consistent with obtaining diagnostic information, achieved through proper selection criteria, optimal technique, quality assurance, and rectangular collimation (Correct answer)
All Lateral And Rotational Adjustments — it refers to patient positioning
Anterior Lateral Anteroposterior Radiograph Assessment — a specific projection technique
It refers to the storage protocol for radiographic films

Correct answer: As Low As Reasonably Achievable (or Practicable) — radiation doses should be kept to the minimum consistent with obtaining diagnostic information, achieved through proper selection criteria, optimal technique, quality assurance, and rectangular collimation

ALARA/ALARP is the overriding principle of radiation protection requiring that all radiation exposures be kept as low as reasonably achievable while obtaining the necessary diagnostic information. In dental practice, this is achieved through: using selection criteria to justify each exposure, choosing the lowest effective dose (optimal kV, mA, exposure time), using rectangular collimation (reduces dose by up to 60% compared to round collimation), using fast-speed film or digital sensors, proper quality assurance programmes, and avoiding repeat exposures through good technique.

Question 41: The four muscles of mastication are all innervated by which nerve?

Maxillary nerve (CN V2)
All three divisions of the trigeminal nerve
Facial nerve (CN VII)
Mandibular nerve (CN V3) (Correct answer)

Correct answer: Mandibular nerve (CN V3)

The masseter, temporalis, medial pterygoid, and lateral pterygoid are all supplied by the mandibular division of the trigeminal nerve (CN V3), reflecting their shared origin from the first pharyngeal arch mesoderm.

Question 42: Under the GDC Standards for the Dental Team, which duty is defined as 'putting patients' interests first'?

Beneficence
Confidentiality
Candour
Patient-centred care (Correct answer)

Correct answer: Patient-centred care

GDC Standard 1 'Put patients' interests first' encompasses the concept of patient-centred care, ensuring decisions are made with the patient's wellbeing as the primary consideration.

Question 43: What is the approximate pH at which enamel begins to demineralise?

5.5 (Correct answer)
6.2
7.0
4.0

Correct answer: 5.5

The critical pH for enamel demineralisation is approximately 5.5, below which the oral environment becomes undersaturated with respect to hydroxyapatite.

Question 44: Carbamazepine is the drug of first choice for management of:

Burning mouth syndrome
Trigeminal neuralgia (Correct answer)
Temporomandibular disorders
Atypical facial pain

Correct answer: Trigeminal neuralgia

Carbamazepine, a sodium channel blocker, is the first-line treatment for trigeminal neuralgia due to its demonstrated efficacy in reducing the frequency and intensity of attacks.

Question 45: According to the National Institute for Health and Care Excellence (NICE) Technology Appraisal Guidance [TA1], which of the following is an accepted indication for the surgical removal of an impacted third molar?

A single, mild episode of pericoronitis that resolved with local measures.
To prevent potential future crowding of the anterior teeth.
The patient is asymptomatic but the tooth is horizontally impacted.
The presence of non-treatable pulpal pathology in the third molar. (Correct answer)

Correct answer: The presence of non-treatable pulpal pathology in the third molar.

NICE guidance TA1 explicitly states that the prophylactic removal of pathology-free impacted third molars should be discontinued. It lists specific pathological conditions as indications for removal, which include non-treatable pulpal and/or periapical pathology, unrestorable caries, cellulitis, abscesses, and cysts. A single mild episode of pericoronitis is not a firm indication, though recurrent or severe episodes are. Preventing future crowding is not an evidence-based indication for removal.

Question 46: A patient with chronic kidney disease (eGFR 20 mL/min) requires a dental prescription for pain relief. Which analgesic is contraindicated and what is the recommended alternative?

NSAIDs (e.g., ibuprofen) are contraindicated as they reduce renal blood flow and can precipitate acute kidney injury; paracetamol is the recommended first-line analgesic (Correct answer)
All analgesics are safe in renal impairment
Codeine is contraindicated; use diclofenac instead
Paracetamol is contraindicated; use ibuprofen instead

Correct answer: NSAIDs (e.g., ibuprofen) are contraindicated as they reduce renal blood flow and can precipitate acute kidney injury; paracetamol is the recommended first-line analgesic

NSAIDs are contraindicated in patients with significant renal impairment (eGFR <30 mL/min) because they inhibit prostaglandin-mediated renal blood flow regulation, which can precipitate acute kidney injury, fluid retention, and hyperkalaemia. Paracetamol is the first-line analgesic in renal impairment as it is hepatically metabolised. If stronger analgesia is needed, codeine can be used with caution (reduced doses) as its metabolites accumulate in renal failure.

Question 47: Which investigation is most appropriate to confirm the diagnosis of pemphigus vulgaris?

Serum IgE levels
Patch testing
Direct immunofluorescence of perilesional mucosa (Correct answer)
Culture of blister fluid

Correct answer: Direct immunofluorescence of perilesional mucosa

Direct immunofluorescence of perilesional mucosa demonstrates intercellular IgG and C3 deposition in a 'chicken wire' or 'fish net' pattern, confirming pemphigus vulgaris.

Question 48: A patient presents with a swelling in the floor of the mouth that is fluctuant, translucent blue, and recurrent. It collapses on aspiration and refills. What is the most likely diagnosis?

Ludwig's angina
Dermoid cyst
Ranula (Correct answer)
Sublingual gland tumour

Correct answer: Ranula

A ranula is a mucous extravasation cyst or retention cyst arising from the sublingual gland. It presents as a fluctuant, translucent blue swelling in the floor of the mouth that may recur after aspiration. A simple ranula is confined to the floor of the mouth; a plunging ranula extends below the mylohyoid muscle into the neck. Definitive treatment usually requires excision of the sublingual gland.

Question 49: Which virus is most strongly associated with the development of oral hairy leukoplakia?

EBV (Correct answer)
HSV-1
CMV
HPV-16

Correct answer: EBV

Oral hairy leukoplakia is caused by Epstein-Barr virus (EBV) replication in epithelial cells, typically occurring in immunocompromised individuals.

Question 50: A conventional glass ionomer cement (GIC) is selected for a Class V restoration. Which of the following statements most accurately describes the primary bonding mechanism of this material to tooth structure?

It forms a micromechanical bond via a resin-infiltrated hybrid layer.
It relies solely on mechanical undercuts in the cavity preparation for retention.
It sets via an acid-base reaction and forms a true chemical bond through ionic exchange. (Correct answer)
It requires a separate phosphoric acid etchant and a bonding agent to adhere.

Correct answer: It sets via an acid-base reaction and forms a true chemical bond through ionic exchange.

Conventional glass ionomer cements are self-adhesive materials. Their setting is an acid-base reaction between the polyalkenoic acid liquid and the basic fluoroaluminosilicate glass powder. Adhesion to the tooth occurs via a chemical bond, specifically an ionic exchange between the carboxyl groups of the polyacid and calcium ions in the hydroxyapatite of enamel and dentine.

Question 51: Koplik's spots in the oral mucosa are a prodromal feature of:

Hand foot and mouth disease
Varicella
Scarlet fever
Measles (Correct answer)

Correct answer: Measles

Koplik's spots (bluish-white spots on a red background on the buccal mucosa opposite the molars) appear 1–2 days before the skin rash of measles.

Question 52: According to the Ionising Radiation (Medical Exposure) Regulations 2017 (IRMER), who holds the primary legal responsibility for the justification of a dental radiograph exposure?

The IRMER Practitioner (Correct answer)
The Practice Owner (Employer)
The Radiographer
The Radiation Protection Adviser (RPA)

Correct answer: The IRMER Practitioner

IRMER 2017 places the legal responsibility for justifying an individual medical exposure on the 'Practitioner'. This individual must be a registered healthcare professional who is entitled to take responsibility for an exposure. In dentistry, this is typically the dentist or another appropriately trained dental care professional who has decided the exposure is necessary.

Question 53: Which classification is used to grade epithelial dysplasia in oral precancerous lesions?

TNM staging
Bethesda system
WHO 2005 grading (Correct answer)
Broder's grading

Correct answer: WHO 2005 grading

The WHO 2005 system grades oral epithelial dysplasia as mild, moderate or severe (or uses a binary low-grade/high-grade system) based on architectural and cytological criteria.

Question 54: Which cells phagocytose bone and hard tissue in the periapical region during root resorption?

Fibroblasts
Cementoblasts
Odontoclasts (Correct answer)
Osteoblasts

Correct answer: Odontoclasts

Odontoclasts (also termed dentinoclasts or cementoclasts) are multinucleate cells analogous to osteoclasts that resorb dental hard tissues.

Question 55: The greater palatine nerve supplies the palatal mucosa in which region?

Soft palate and uvula
Anterior hard palate only (behind upper incisors)
Anterior two-thirds of the hard palate
Hard palate from the canine region to the posterior margin (Correct answer)

Correct answer: Hard palate from the canine region to the posterior margin

The greater palatine nerve, emerging from the greater palatine foramen, supplies the mucosa of the hard palate from the canine tooth region posteriorly to the soft palate junction.

Question 56: Following the completion of comprehensive fixed appliance therapy, which factor is considered a primary contributor to long-term post-treatment relapse, such as late lower incisor crowding?

Inherent memory of the periodontal ligament fibres.
Contraction of the supracrestal gingival fibres.
Persistent soft tissue pressures (e.g., tongue thrust).
Unfavourable continued facial growth. (Correct answer)

Correct answer: Unfavourable continued facial growth.

While all listed factors can contribute to relapse, unfavourable continued facial growth is a primary reason for long-term occlusal changes, particularly late lower incisor crowding. Even after orthodontic treatment, the face and jaws continue to mature, with late mandibular growth often leading to changes in the incisor relationship. This understanding underpins the modern UK orthodontic consensus that retention should be considered a lifelong commitment.

Question 57: A new patient presents for their initial oral health assessment. Which of the following components is NOT considered a mandatory part of the extra-oral examination as per standard UK dental practice guidelines?

Palpation of the cervical lymph nodes
Assessment of the temporomandibular joint (TMJ)
Auscultation of the carotid arteries for bruits (Correct answer)
Visual inspection of the skin of the head and neck

Correct answer: Auscultation of the carotid arteries for bruits

A comprehensive extra-oral examination in UK dentistry includes visual inspection of the head and neck, palpation of salivary glands and cervical lymph nodes, and assessment of TMJ function. Auscultation of the carotid arteries for bruits is a specialised medical procedure not routinely performed during a dental assessment and is outside the scope of general dental practice.

Question 58: A 55-year-old female presents with bilateral white lace-like striations on the buccal mucosa with areas of erythema and ulceration. She reports episodes of soreness. What is the most likely diagnosis?

Oral squamous cell carcinoma
Oral leukoplakia
Oral lichen planus (Correct answer)
Candidiasis

Correct answer: Oral lichen planus

The bilateral white lace-like striations (Wickham's striae) on the buccal mucosa with areas of erythema and erosion are characteristic of oral lichen planus. This chronic mucocutaneous condition affects approximately 1-2% of the population, predominantly middle-aged women. The reticular form is the most common pattern, while the erosive form causes the most symptoms. It requires long-term monitoring due to a small malignant transformation risk (approximately 1-2%).

Question 59: Which type of incision is most commonly used for surgical removal of an impacted lower third molar, and what structures must be carefully protected?

A midline mandibular incision, protecting the mental nerve
A submandibular (Risdon) incision, protecting the marginal mandibular branch of the facial nerve
A vestibular incision only, with no nerve structures at risk
A triangular or envelope mucoperiosteal flap with a relieving incision distal to the second molar, protecting the lingual nerve and inferior alveolar nerve (Correct answer)

Correct answer: A triangular or envelope mucoperiosteal flap with a relieving incision distal to the second molar, protecting the lingual nerve and inferior alveolar nerve

The standard approach uses a triangular mucoperiosteal flap with a relieving incision distal and buccal to the lower second molar, extending forward along the buccal sulcus. The lingual nerve is at risk as it lies in close proximity to the lingual plate of bone in the third molar region, and the inferior alveolar nerve runs in the canal beneath the roots. Careful flap design, controlled bone removal, and avoidance of lingual soft tissue retraction minimise nerve injury risk.

Question 60: In the UK, the care of children with a cleft lip and/or palate is managed by centralised NHS cleft services following a specific treatment timeline. At approximately what age is the primary surgical repair of a cleft lip typically performed?

12 months
18 months
Within the first week of life
3 months (Correct answer)

Correct answer: 3 months

The standard protocol in UK cleft centres is to perform the primary lip repair surgery when the baby is around 3 months old. This timing allows the infant to establish feeding and gain weight, and is often guided by the 'rule of tens' (e.g., 10 weeks old, 10 pounds weight). The repair of a cleft palate is performed later, typically between 6 and 12 months of age.

Question 61: A radiolucent lesion is found at the apex of a non-vital lower premolar. Histological examination reveals a cyst lined by non-keratinised stratified squamous epithelium with arcading pattern and cholesterol clefts in the wall. What is the most likely diagnosis?

Odontogenic keratocyst
Lateral periodontal cyst
Dentigerous cyst
Radicular (periapical) cyst (Correct answer)

Correct answer: Radicular (periapical) cyst

A radicular cyst is the most common odontogenic cyst, arising from epithelial cell rests of Malassez stimulated by inflammation from a non-vital tooth. The characteristic histological features include non-keratinised stratified squamous epithelium with an arcading (net-like) pattern, and the cyst wall typically contains chronic inflammatory cells, cholesterol clefts surrounded by multinucleated giant cells, and haemosiderin deposits.

Question 62: When selecting an all-ceramic material for a full-coverage crown on a maxillary second molar in a patient with evidence of bruxism, which of the following materials offers the highest flexural strength and fracture toughness, making it the most suitable choice?

Lithium disilicate glass-ceramic
Leucite-reinforced glass-ceramic
Monolithic zirconia (Correct answer)
Feldspathic porcelain

Correct answer: Monolithic zirconia

Monolithic zirconia has superior mechanical properties compared to other dental ceramics, with a flexural strength often exceeding 900-1200 MPa. This makes it the material of choice for posterior crowns in high-stress situations, such as in patients who are bruxists. Lithium disilicate, while having excellent aesthetics, has a lower flexural strength (around 400 MPa) and is more susceptible to fracture under heavy occlusal loads. Feldspathic and leucite-reinforced ceramics are weaker still and are not indicated for high-load posterior restorations.

Question 63: A dental practice is conducting a routine quality assurance audit of its digital intraoral radiographs. According to the 'Guidance Notes for Dental Practitioners on the Safe Use of X-ray Equipment (2nd Edition)', what is the minimum target for 'diagnostically acceptable' radiographs?

Not less than 95% (Correct answer)
Exactly 100%
Not less than 85%
Not less than 90%

Correct answer: Not less than 95%

The guidance co-published by Public Health England and the FGDP(UK) specifies quality assurance targets. For digital radiography, the target for diagnostically acceptable images (rated 'A') is not less than 95%. For film-based systems, the target is slightly lower at not less than 90%.

Question 64: Which structure of the cranial base completes its growth earliest and is therefore commonly used as a stable reference structure for superimposition in longitudinal cephalometric analysis?

Mandibular symphysis
Maxilla
Spheno-occipital synchondrosis
Anterior cranial base (Sella-Nasion line) (Correct answer)

Correct answer: Anterior cranial base (Sella-Nasion line)

The anterior cranial base, represented cephalometrically by the Sella-Nasion (S-N) line, completes its growth relatively early (around age 7). Its stability makes it an invaluable reference plane for superimposing serial cephalometric radiographs to assess treatment changes and subsequent facial growth. The spheno-occipital synchondrosis is a major growth centre that fuses in the late teens, while the maxilla and mandible undergo significant growth throughout puberty.

Question 65: During the extraction of a maxillary first molar, a 3mm oro-antral communication (OAC) is created. The sinus lining appears intact and the patient is healthy with no history of sinusitis. What is the most appropriate immediate management?

Pack the socket with antiseptic gauze and review the patient in one week.
Provide post-operative instructions to avoid nose-blowing and allow healing by secondary intention. (Correct answer)
Refer the patient immediately to an oral and maxillofacial surgery department for primary closure.
Surgically close the defect with a buccal advancement flap and prescribe antibiotics.

Correct answer: Provide post-operative instructions to avoid nose-blowing and allow healing by secondary intention.

For a small oro-antral communication (generally considered <5mm) with an intact sinus membrane in a healthy patient, the blood clot is often sufficient to seal the defect and allow for spontaneous healing. The most critical immediate step is to provide clear post-operative instructions to protect the clot, such as avoiding nose-blowing, sneezing with the mouth open, and using straws. Surgical closure with a flap is typically reserved for larger defects (>5mm) or if conservative management fails.

Question 66: A dentist is planning to restore a carious primary molar in a 6-year-old child using the Hall Technique. Radiographic and clinical examination are essential to determine suitability. Which of the following findings is a definitive contraindication for this technique?

Clinical signs of a dental abscess related to the tooth. (Correct answer)
The child has moderate dental anxiety.
The carious lesion involves two surfaces of the tooth.
A clear band of dentine is visible between the caries and the pulp on the radiograph.

Correct answer: Clinical signs of a dental abscess related to the tooth.

The Hall Technique is a biological approach that seals caries within the tooth, and it is only suitable for vital teeth with no evidence of irreversible pulpitis or infection. Clinical signs of a dental abscess (such as swelling, a sinus tract, or spontaneous pain) or radiographic evidence of periradicular pathology are absolute contraindications, as the tooth is non-vital and requires extraction or pulpectomy. The technique is often used for anxious children and is designed for multi-surface lesions. A clear band of dentine on the radiograph is an indicator that the technique may be suitable.

Question 67: What are the boundaries of the 'anatomical snuffbox' and which artery is at risk during surgical procedures in this region?

Bounded by the tendons of abductor pollicis longus/extensor pollicis brevis and extensor pollicis longus; the radial artery passes through its floor (Correct answer)
Bounded by the buccinator and orbicularis oris; the buccal artery is at risk
Bounded by the masseter and medial pterygoid; the facial artery is at risk
Bounded by the sternomastoid and trapezius; the external jugular vein is at risk

Correct answer: Bounded by the tendons of abductor pollicis longus/extensor pollicis brevis and extensor pollicis longus; the radial artery passes through its floor

The anatomical snuffbox is bounded laterally by the tendons of abductor pollicis longus and extensor pollicis brevis, and medially by the tendon of extensor pollicis longus. The radial artery crosses its floor, and the cephalic vein crosses superficially. While not directly related to oral surgery, knowledge of upper limb anatomy is tested in MFDS Part 1 as part of general surgical anatomy.

Question 68: An 8-year-old child attends for a check-up. The dentist observes multiple bruises of varying colours on the child's arms and notes that the child seems unusually anxious. The parent dismisses this as clumsiness. What is the most appropriate immediate action for the dentist to take in line with UK safeguarding principles?

Document the findings meticulously and discuss concerns immediately with the practice's designated safeguarding lead. (Correct answer)
Confront the parent directly about the suspicion of non-accidental injury.
Immediately telephone the police to report a case of child abuse.
Treat the child's dental needs and schedule a review in one month to monitor the situation.

Correct answer: Document the findings meticulously and discuss concerns immediately with the practice's designated safeguarding lead.

GDC Standard 8.5 states dental professionals must raise concerns about possible abuse or neglect. [2] UK safeguarding procedures require a structured approach. The correct first step is to make a detailed, contemporaneous record of all clinical findings and concerns and then to discuss the situation with the practice's designated safeguarding lead. [2, 23] This individual is trained to advise on the next steps, which typically involves referral to the local authority's children's social care services. Confronting the parent or simply waiting are inappropriate and could place the child at further risk. [2, 35]

Question 69: According to the National Institute for Health and Care Excellence (NICE) guidelines (CG19), what is the maximum recommended recall interval between oral health reviews for an adult patient aged 18 or over who has repeatedly demonstrated they can maintain good oral health?

6 months
24 months (Correct answer)
12 months
36 months

Correct answer: 24 months

NICE Clinical Guideline 19 (Dental checks: intervals between oral health reviews) states that the longest interval between oral health reviews for patients aged 18 years and older should be 24 months. This is based on a risk assessment approach, moving away from the traditional 6-month recall for all patients.

Question 70: What are the radiographic features of a dentigerous cyst on a dental panoramic tomograph?

A well-defined, unilocular radiolucency with a corticated margin, attached to the cemento-enamel junction of an unerupted tooth and surrounding its crown (Correct answer)
A multilocular radiolucency with a soap-bubble appearance not associated with any tooth
A diffuse, ill-defined radiopacity surrounding an erupted tooth
A radiopaque mass replacing the normal tooth structure

Correct answer: A well-defined, unilocular radiolucency with a corticated margin, attached to the cemento-enamel junction of an unerupted tooth and surrounding its crown

A dentigerous cyst appears radiographically as a well-defined, unilocular radiolucency with a corticated (sclerotic) border, attached to the cemento-enamel junction of an unerupted tooth, enveloping its crown. The pericoronal radiolucency must exceed 2.5-3 mm to be considered pathological (normal follicular space is up to 2-2.5 mm). It may displace the tooth or cause resorption of adjacent teeth. The most commonly affected teeth are lower third molars, upper canines, and upper third molars.

Question 71: Which class of antihypertensive drugs is most commonly associated with drug-induced gingival enlargement?

Calcium channel blockers (e.g., nifedipine, amlodipine) (Correct answer)
Angiotensin II receptor blockers (e.g., losartan)
ACE inhibitors (e.g., ramipril)
Beta-blockers (e.g., atenolol)

Correct answer: Calcium channel blockers (e.g., nifedipine, amlodipine)

Calcium channel blockers, particularly nifedipine and amlodipine, are the antihypertensive drugs most commonly associated with gingival enlargement (overgrowth). The mechanism involves inhibition of calcium-dependent collagenase, reducing collagen breakdown in the gingival tissues. The prevalence is approximately 6-15% for nifedipine. Other drugs causing gingival enlargement include ciclosporin (immunosuppressant) and phenytoin (anticonvulsant). Management includes meticulous oral hygiene, and drug substitution if possible.

Question 72: What is the typical effective dose of a dental panoramic tomograph (DPT/OPG) and how does it compare to other dental radiographic examinations?

A DPT gives a dose of approximately 50 mSv, much higher than a chest X-ray
A DPT gives an effective dose of approximately 5-25 microsieverts, equivalent to approximately 2-8 periapical radiographs, and much less than a medical CT scan (Correct answer)
A DPT gives approximately 1 millisievert, equivalent to a full mouth series
A DPT gives zero radiation dose as it uses ultrasound

Correct answer: A DPT gives an effective dose of approximately 5-25 microsieverts, equivalent to approximately 2-8 periapical radiographs, and much less than a medical CT scan

A DPT delivers an effective dose of approximately 5-25 μSv (microsieverts), depending on the equipment and patient size. This is equivalent to approximately 2-8 intraoral periapical radiographs (each approximately 1-8 μSv) or approximately 1-3 days of natural background radiation. For comparison, a small-volume CBCT scan delivers approximately 20-200 μSv, a full medical CT head approximately 2,000 μSv, and annual UK background radiation approximately 2,700 μSv. These comparisons help in justifying exposures under IRMER and explaining risk to patients.

Question 73: Hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu disease) presents with oral telangiectases and:

Factor VIII deficiency
Recurrent epistaxis and mucocutaneous telangiectases (Correct answer)
Thrombocytopenia
Prolonged PT and APTT

Correct answer: Recurrent epistaxis and mucocutaneous telangiectases

HHT is an autosomal dominant condition causing abnormal vascular structures (telangiectases and AVMs) leading to recurrent spontaneous bleeds, particularly epistaxis.

Question 74: Ranula is a mucocele arising from which gland?

Parotid gland
Submandibular gland
Minor salivary glands
Sublingual gland (Correct answer)

Correct answer: Sublingual gland

A ranula is a pseudocyst (extravasation mucocele) arising from the sublingual gland, producing a bluish, fluctuant swelling in the floor of the mouth.

Question 75: A 45-year-old man presents with non-painful, non-wipeable, white, corrugated lesions along the lateral borders of his tongue. This clinical sign, known as oral hairy leukoplakia, is most strongly associated with an underlying infection by which virus?

Herpes Simplex Virus (HSV-1)
Varicella-Zoster Virus (VZV)
Epstein-Barr Virus (EBV) (Correct answer)
Human Papillomavirus (HPV)

Correct answer: Epstein-Barr Virus (EBV)

Oral hairy leukoplakia is caused by the Epstein-Barr Virus (EBV). It is not a premalignant condition itself but serves as an important clinical marker for immunosuppression, most classically associated with HIV infection. Its presence often indicates a declining immune status.

Question 76: Which foramen on the medial aspect of the mandibular ramus transmits the inferior alveolar nerve and vessels?

Incisive foramen
Greater palatine foramen
Mandibular foramen (Correct answer)
Mental foramen

Correct answer: Mandibular foramen

The inferior alveolar nerve and artery enter the mandibular canal through the mandibular foramen, located on the medial surface of the ramus, guarded anteriorly by the lingula.

Question 77: Which type of collagen predominates in the pulp and dentine matrix?

Type II
Type I (Correct answer)
Type IV
Type III

Correct answer: Type I

Type I collagen is the major fibrillar collagen of dentine and pulp, providing tensile strength to the matrix.

Question 78: The mylohyoid nerve, which supplies the mylohyoid muscle, arises from which parent nerve?

Inferior alveolar nerve (Correct answer)
Buccal nerve
Mental nerve
Lingual nerve

Correct answer: Inferior alveolar nerve

The mylohyoid nerve is a branch of the inferior alveolar nerve arising just before it enters the mandibular foramen; it runs in the mylohyoid groove to supply the mylohyoid muscle and the anterior belly of the digastric.

Question 79: A 45-year-old new patient is diagnosed with generalised Stage III Grade B periodontitis. In line with the British Society of Periodontology (BSP) S3 Level Clinical Practice Guideline, what is the mandatory first step of active periodontal therapy?

Immediate subgingival instrumentation (root surface debridement) under local anaesthesia.
A course of systemic antibiotics combined with full mouth disinfection.
Supragingival professional mechanical plaque removal (PMPR), detailed oral hygiene instruction, and risk factor control. (Correct answer)
Referral for surgical periodontal therapy.

Correct answer: Supragingival professional mechanical plaque removal (PMPR), detailed oral hygiene instruction, and risk factor control.

The BSP S3 guideline outlines a stepwise approach. Step 1 is foundational and must be completed for all periodontitis patients. It focuses on building patient motivation, providing personalised oral hygiene instruction, controlling risk factors (like smoking or poor glycaemic control), and performing supragingival professional mechanical plaque removal. Subgingival instrumentation (Step 2) is only undertaken after the patient has demonstrated engagement and improvement in plaque control following Step 1.

Question 80: In line with the UK's implementation of the Minamata Convention on Mercury, the use of dental amalgam is restricted. In which of the following patient groups is the use of dental amalgam prohibited, except where deemed strictly necessary by the practitioner for the specific medical needs of the patient?

Children under 15 years of age, and pregnant or breastfeeding women. (Correct answer)
Patients undergoing fixed orthodontic appliance therapy.
Adult patients over the age of 65 requiring multi-surface posterior restorations.
Patients with a known allergy to base metals.

Correct answer: Children under 15 years of age, and pregnant or breastfeeding women.

The Minamata Convention on Mercury is a global treaty to protect human health and the environment from mercury. In the UK, as in the EU, this has led to specific restrictions on the use of dental amalgam. From 1 July 2018, dental amalgam must not be used for the dental treatment of deciduous teeth, of children under 15 years, and of pregnant or breastfeeding women, unless there is a specific medical necessity.

Question 81: A 65-year-old patient, who is a heavy smoker, presents with a painless, indurated ulcer on the lateral border of the tongue that has persisted for 4 weeks. According to NICE guideline [NG12] 'Suspected cancer: recognition and referral', what is the most appropriate immediate action?

Advise the patient to stop smoking and review the lesion's progress in two weeks.
Take an incisional biopsy in the primary care dental practice immediately.
Prescribe a topical antiseptic mouthwash and schedule a review in one month.
Refer the patient for an urgent appointment under the 'two-week wait' pathway for suspected cancer. (Correct answer)

Correct answer: Refer the patient for an urgent appointment under the 'two-week wait' pathway for suspected cancer.

NICE guideline [NG12] specifies that an unexplained oral ulceration or mass persisting for more than 3 weeks warrants an urgent referral under the 'two-week wait' pathway to rule out malignancy. Delaying referral for review or attempting a biopsy in a primary care setting for a lesion highly suspicious of squamous cell carcinoma is inappropriate and goes against established UK national guidance.

Question 82: Which viral infection is most strongly associated with oral hairy leukoplakia, and on which part of the oral mucosa does it typically present?

Herpes simplex virus (HSV) on the lips
Cytomegalovirus (CMV) on the gingiva
Epstein-Barr virus (EBV) on the lateral borders of the tongue (Correct answer)
Human papillomavirus (HPV) on the palate

Correct answer: Epstein-Barr virus (EBV) on the lateral borders of the tongue

Oral hairy leukoplakia is caused by Epstein-Barr virus (EBV) replication within the epithelial cells of the tongue. It presents as white, corrugated, non-removable patches on the lateral borders of the tongue, often bilateral. It is strongly associated with immunosuppression, particularly HIV/AIDS (where it may be the presenting sign), but also occurs in other immunocompromised states. Histologically, it shows epithelial hyperplasia with a corrugated surface, koilocyte-like cells, and absence of inflammatory infiltrate.

Question 83: Which cells are responsible for forming dentine?

Osteoblasts
Cementoblasts
Ameloblasts
Odontoblasts (Correct answer)

Correct answer: Odontoblasts

Odontoblasts are the specialised cells derived from neural crest cells that synthesise and secrete the organic matrix of dentine.

Question 84: A 13-year-old patient presents for an orthodontic assessment. The clinical examination reveals a Class II division 1 incisor relationship with an overjet of 7mm. All other occlusal features are within normal limits. According to the Index of Orthodontic Treatment Need (IOTN), what is the Dental Health Component (DHC) grade for this patient?

3a
5a
4a (Correct answer)
4d

Correct answer: 4a

The IOTN DHC is used in the UK to assess the need for orthodontic treatment on dental health grounds. Grade 4 indicates a 'great' need for treatment, which typically qualifies for NHS funding. An overjet greater than 6mm but less than or equal to 9mm is specifically classified as grade 4a.

Question 85: A patient taking a selective serotonin reuptake inhibitor (SSRI) antidepressant requires dental treatment. What is the most clinically significant drug interaction to be aware of?

SSRIs potentiate the effect of local anaesthetics, causing prolonged numbness
SSRIs cause severe hypertension when combined with adrenaline-containing local anaesthetics
SSRIs have no clinically significant interactions relevant to dentistry
SSRIs inhibit platelet aggregation, increasing the risk of post-operative bleeding, and there is a potential interaction with tramadol increasing the risk of serotonin syndrome (Correct answer)

Correct answer: SSRIs inhibit platelet aggregation, increasing the risk of post-operative bleeding, and there is a potential interaction with tramadol increasing the risk of serotonin syndrome

SSRIs (e.g., fluoxetine, sertraline, citalopram) inhibit serotonin reuptake in platelets, impairing platelet aggregation and increasing bleeding risk, particularly when combined with NSAIDs or aspirin. Additionally, tramadol (sometimes prescribed for dental pain) combined with SSRIs can precipitate serotonin syndrome — a potentially life-threatening condition with agitation, hyperthermia, and muscle rigidity. Paracetamol with codeine is a safer analgesic choice for these patients.

Question 86: Which condition is characterised by episodic severe hypertension, headache and sweating due to excess catecholamine secretion?

Conn's syndrome
Cushing's syndrome
Phaeochromocytoma (Correct answer)
Addison's disease

Correct answer: Phaeochromocytoma

Phaeochromocytoma is a catecholamine-secreting tumour of chromaffin cells of the adrenal medulla, causing episodic or sustained hypertension with severe headache, sweating and palpitations.

Question 87: On a dental panoramic tomograph (DPT/OPG), which anatomical structures are commonly misidentified as pathology?

The mental foramen, incisive canal, maxillary sinus floor, and the ghost image of the opposite mandibular angle (Correct answer)
No normal structures are ever confused with pathology
The tonsils and adenoids are the only structures commonly misidentified
Only the zygomatic arch can be misidentified

Correct answer: The mental foramen, incisive canal, maxillary sinus floor, and the ghost image of the opposite mandibular angle

Common normal structures misidentified as pathology on DPT include: the mental foramen (mimics periapical radiolucency of premolars), incisive canal (midline radiolucency), maxillary sinus (radiolucency over premolar/molar apices), nasal fossa (radiolucency over incisor apices), ghost images (contralateral structures projected to the opposite side), the submandibular fossa (radiolucency in the posterior mandible), and the external oblique ridge. Understanding the normal radiographic anatomy of the DPT is essential to avoid misdiagnosis.

Question 88: According to General Dental Council (GDC) standards, what is the minimum number of people who must be available to deal with a potential medical emergency when dental treatment is planned to take place?

One GDC registrant and one first-aid trained receptionist.
Three, including one non-clinical member of staff to call emergency services.
One, provided they are a GDC registered dentist.
Two. (Correct answer)

Correct answer: Two.

The GDC's 'Standards for the Dental Team' guidance explicitly states that there must be arrangements for at least two people to be available to deal with medical emergencies when treatment is planned. This ensures that one person can attend to the patient while another can assist, retrieve equipment, or call for help, forming an effective team response.

Question 89: What are the characteristic histological features of oral verrucous carcinoma?

Spindle cells with extensive areas of necrosis
A well-differentiated, exophytic, broad-based squamous neoplasm with a verrucous surface, pushing (rather than infiltrating) deep margins, minimal cytological atypia, and keratin-filled clefts (Correct answer)
Basaloid cells arranged in nests with peripheral palisading
Poorly differentiated cells with frequent mitoses invading deeply into muscle

Correct answer: A well-differentiated, exophytic, broad-based squamous neoplasm with a verrucous surface, pushing (rather than infiltrating) deep margins, minimal cytological atypia, and keratin-filled clefts

Verrucous carcinoma is a variant of well-differentiated squamous cell carcinoma with a verrucous (warty) exophytic growth pattern. Key histological features include broad, club-shaped rete ridges that push into the connective tissue with a well-defined deep margin (rather than irregular infiltration), minimal cytological atypia, and keratin-filled clefts ('church spire' keratinisation). Despite being locally destructive, it rarely metastasises. Diagnosis requires a deep biopsy to demonstrate the pushing margins.

Question 90: Which fascial space communicates directly with the infratemporal fossa and is targeted during an inferior alveolar nerve block?

Parapharyngeal space
Temporal space
Pterygomandibular space (Correct answer)
Buccal space

Correct answer: Pterygomandibular space

The pterygomandibular space, bounded medially by the medial pterygoid muscle and laterally by the ramus of the mandible, communicates directly with the infratemporal fossa superiorly and contains the inferior alveolar nerve and vessels.

Question 91: A 24-year-old patient presents with a deep carious lesion in the mandibular first molar (LR6). The tooth is asymptomatic and responds normally to sensibility testing. A radiograph shows the lesion extending into the pulpal third of the dentine. According to contemporary minimally invasive dentistry principles widely accepted in the UK, what is the most appropriate management for the deepest part of the cavity?

Immediate placement of a calcium hydroxide liner without any caries excavation to promote pulpal healing.
Selective removal of caries, leaving soft, wet, necrotic dentine directly over the pulp to avoid exposure.
Selective removal of caries to leave firm, leathery dentine in the pulpal aspect, having secured a peripheral seal on sound dentine. (Correct answer)
Complete removal of all caries until 'hard' or 'scratchy' dentine is felt over the pulp.

Correct answer: Selective removal of caries to leave firm, leathery dentine in the pulpal aspect, having secured a peripheral seal on sound dentine.

Contemporary evidence supports selective caries removal to preserve pulp vitality in deep, asymptomatic lesions. The goal is to remove the outer, heavily infected and non-remineralisable dentine while preserving the deeper, affected but repairable dentine. This involves clearing the cavity walls and enamel-dentine junction to sound tissue to ensure an effective peripheral seal, but leaving firm or leathery dentine directly over the pulp to avoid iatrogenic exposure. Complete removal to hard dentine risks unnecessary pulp exposure, while leaving soft, wet dentine is not recommended.

Question 92: Which muscle protracts the mandibular condyle during mouth opening?

Masseter
Lateral pterygoid (Correct answer)
Medial pterygoid
Temporalis

Correct answer: Lateral pterygoid

The inferior head of the lateral pterygoid contracts during mouth opening, pulling the condyle and articular disc anteriorly (protraction), while the posterior fibres of temporalis retract the condyle on closing.

Question 93: Which feature distinguishes Crohn's disease from ulcerative colitis in oral manifestations?

Pyostomatitis vegetans is only in Crohn's
Aphthous ulcers are exclusive to UC
Cobblestone buccal mucosa and lip swelling occur in Crohn's (Correct answer)
Geographic tongue is specific to UC

Correct answer: Cobblestone buccal mucosa and lip swelling occur in Crohn's

Oral Crohn's disease produces characteristic cobblestone (polypoid) buccal mucosa, lip swelling (orofacial granulomatosis) and linear ulcers not seen in UC.

Question 94: Under the General Dental Council's (GDC) Enhanced CPD scheme, dentists must complete 100 hours of CPD over a five-year cycle. Which statement accurately describes a core requirement of this scheme?

CPD hours are only valid if the activity is undertaken within the UK.
Dentists must submit their full CPD log to the GDC annually for approval.
All 100 hours must be classified as 'verifiable' CPD. (Correct answer)
A minimum of 50 hours must be from hands-on clinical courses.

Correct answer: All 100 hours must be classified as 'verifiable' CPD.

A fundamental change introduced with the Enhanced CPD scheme is that all claimed hours must be 'verifiable'. [16] This means there must be evidence of completion and the activity must have clear aims, objectives, and learning outcomes. The previous system allowed for non-verifiable CPD, but this is no longer the case. [16] Dentists must make an annual statement of hours completed but are only required to submit the full log if requested for an audit. [7] There is no prescribed split between types of activity or geographical location.

Question 95: A patient with a prosthetic heart valve presents for a dental extraction. According to current NICE guidelines (2016 update), what antibiotic prophylaxis is recommended?

Erythromycin 1g orally two hours before the procedure
Clindamycin 600mg intravenously at induction
Amoxicillin 3g orally one hour before the procedure
Antibiotic prophylaxis is NOT routinely recommended by NICE for dental procedures, even in patients with prosthetic heart valves (Correct answer)

Correct answer: Antibiotic prophylaxis is NOT routinely recommended by NICE for dental procedures, even in patients with prosthetic heart valves

NICE Clinical Guideline CG64 (updated 2016) recommends that antibiotic prophylaxis against infective endocarditis should NOT be routinely offered for dental procedures in the UK, including for patients with prosthetic heart valves. This differs from American Heart Association guidelines which still recommend prophylaxis for high-risk patients. The NICE position emphasises that the evidence does not show a clear link between dental procedures and infective endocarditis development.

Question 96: A patient with a history of coeliac disease presents with recurrent aphthous ulceration and angular cheilitis. Blood tests reveal a haemoglobin of 10.2 g/dL. Which deficiency is most likely contributing to the oral manifestations?

Vitamin C deficiency
Iron deficiency secondary to malabsorption (Correct answer)
Vitamin D deficiency
Zinc deficiency

Correct answer: Iron deficiency secondary to malabsorption

Coeliac disease causes malabsorption of iron, folate, and vitamin B12 from the proximal small intestine. Iron deficiency is the most common cause of anaemia in coeliac disease and commonly manifests orally as recurrent aphthous ulceration, angular cheilitis, glossitis (smooth, depapillated tongue), and oral mucosal atrophy. The combination of oral signs with anaemia in a coeliac patient strongly suggests iron deficiency.

Question 97: Which antibiotic is first-line for odontogenic infections in penicillin-allergic patients?

Metronidazole
Clindamycin (Correct answer)
Erythromycin
Ciprofloxacin

Correct answer: Clindamycin

Clindamycin is an appropriate first-line alternative for odontogenic infections in penicillin-allergic patients due to its excellent activity against streptococci and anaerobes.

Question 98: A dentist is restoring a shallow Class V abrasion lesion with composite resin in a patient who reports significant dentine hypersensitivity. To minimise the risk of post-operative sensitivity, which adhesive strategy is generally considered most appropriate?

A two-step self-etch adhesive system (self-etching primer and bond). (Correct answer)
A one-step self-etch adhesive system applied in a single layer.
A selective-enamel etch technique followed by application of a one-step self-etch adhesive.
A three-step total-etch (etch-and-rinse) adhesive system.

Correct answer: A two-step self-etch adhesive system (self-etching primer and bond).

Self-etch adhesive systems are generally associated with a lower risk of post-operative sensitivity compared to total-etch systems, particularly in sensitive areas like Class V lesions. This is because they do not completely remove the smear layer and involve fewer steps, reducing the risk of over-drying or over-etching the dentine, which can leave open dentinal tubules. A two-step self-etch system, with a separate primer and bond, is often considered more reliable and effective at sealing the dentine than a one-step ('all-in-one') system, providing a good balance of reduced sensitivity and effective bonding.

Question 99: Which condition is characterised by multiple dentigerous cysts, odontogenic keratocysts and calcifying jaw cysts as part of a syndrome?

Gardner syndrome
Gorlin-Goltz syndrome (Correct answer)
Paget's disease
Cherubism

Correct answer: Gorlin-Goltz syndrome

Gorlin-Goltz syndrome (naevoid basal cell carcinoma syndrome) is caused by PTCH1 mutation and includes multiple OKCs, basal cell carcinomas and skeletal anomalies.

Question 100: The parotid duct (Stensen's duct) opens into the oral vestibule opposite which tooth?

Upper second molar (Correct answer)
Upper second premolar
Upper first premolar
Upper first molar

Correct answer: Upper second molar

The parotid duct pierces the buccinator muscle and opens at the parotid papilla on the buccal mucosa opposite the upper second molar.

Question 101: A patient presents with multiple jaw cysts. Genetic testing reveals a mutation in the PTCH1 gene. What syndrome is this patient likely to have?

Peutz-Jeghers syndrome
McCune-Albright syndrome
Gorlin-Goltz syndrome (naevoid basal cell carcinoma syndrome) (Correct answer)
Gardner syndrome

Correct answer: Gorlin-Goltz syndrome (naevoid basal cell carcinoma syndrome)

Gorlin-Goltz syndrome (naevoid basal cell carcinoma syndrome) is an autosomal dominant condition caused by mutations in the PTCH1 tumour suppressor gene on chromosome 9q22. Features include multiple odontogenic keratocysts (often presenting in the first decade), multiple basal cell carcinomas (especially after puberty), skeletal anomalies (bifid ribs, spina bifida occulta), calcification of the falx cerebri, palmar/plantar pits, and medulloblastoma in childhood.

Question 102: A 72-year-old patient has been taking oral alendronic acid for osteoporosis for seven years. They require extraction of a mandibular molar. According to SDCEP guidance on Medication-related Osteonecrosis of the Jaw (MRONJ), which factor places this patient in the 'higher risk' category?

The extraction is in the mandible.
The patient has a diagnosis of osteoporosis.
The duration of bisphosphonate use is greater than 5 years. (Correct answer)
The patient's age is over 70.

Correct answer: The duration of bisphosphonate use is greater than 5 years.

The SDCEP guidance categorises patients based on their risk of developing MRONJ. For patients taking oral bisphosphonates for osteoporosis, the duration of therapy is a key risk factor. Use for over 5 years elevates the patient to the 'higher risk' category. Other factors for higher risk include concurrent systemic steroid use or a history of cancer. While mandibular extractions and age are general risk factors, the duration of therapy is the specific criterion listed that defines the higher risk category in the guidance.

Question 103: A patient presents three days after an extraction complaining of severe, radiating pain and a foul taste. The socket appears empty with exposed bone. Which of the following represents the most appropriate initial management for alveolar osteitis (dry socket)?

Prescribe a strong opioid analgesic and advise hourly hot salt water mouthwashes.
Vigorously curette the socket to stimulate bleeding and prescribe a course of amoxicillin.
Take a radiograph to rule out a retained root and then suture the socket closed.
Gently irrigate the socket with warm saline and place an obtundent dressing. (Correct answer)

Correct answer: Gently irrigate the socket with warm saline and place an obtundent dressing.

The management of alveolar osteitis is primarily palliative, aimed at relieving pain and promoting a clean environment for healing. The standard of care is to gently irrigate the socket with an agent like warm saline or chlorhexidine to remove debris, followed by the placement of an obtundent dressing (e.g., Alvogyl) to soothe the exposed bone. Aggressive curettage is contraindicated as it can cause further trauma and delay healing. Systemic antibiotics are not indicated unless there are signs of systemic infection.

Question 104: An Upper Removable Appliance (URA) has been constructed to correct a unilateral posterior crossbite affecting the maxillary first premolars and molars. Which component is essential for providing the force required to achieve the desired buccopalatal expansion?

Z-spring
Adams clasp
Midline expansion screw (Correct answer)
Southend clasp

Correct answer: Midline expansion screw

A midline expansion screw is an active component specifically designed to generate transverse forces to widen the maxillary arch. When activated, it separates the two halves of the appliance, pushing the posterior teeth buccally to correct the crossbite. Adams and Southend clasps provide retention, while a Z-spring is typically used to move a single anterior tooth labially.

Question 105: A 12-year-old patient presents with a well-defined radiolucent area surrounding the crown of an unerupted lower second premolar. What is the most likely diagnosis?

Ameloblastoma
Stafne bone cavity
Dentigerous (follicular) cyst (Correct answer)
Radicular cyst

Correct answer: Dentigerous (follicular) cyst

A dentigerous cyst is the second most common odontogenic cyst, developing from the reduced enamel epithelium and attached to the cemento-enamel junction of an unerupted tooth. It presents as a well-defined unilocular radiolucency surrounding the crown of an unerupted tooth, most commonly lower third molars, upper canines, and lower premolars. Treatment is enucleation with removal of the associated tooth, or marsupialization if the tooth may erupt.

Question 106: Pemphigus vulgaris and mucous membrane pemphigoid are both vesiculobullous conditions affecting the oral mucosa. What is the key histological difference between them?

Pemphigus vulgaris shows granulomatous inflammation; pemphigoid shows eosinophilic infiltrate
Both conditions show identical histological features
Pemphigus vulgaris shows intraepithelial (suprabasal) blistering with acantholysis; mucous membrane pemphigoid shows subepithelial blistering with an intact basal layer (Correct answer)
Pemphigus vulgaris shows subepithelial blistering; pemphigoid shows intraepithelial blistering

Correct answer: Pemphigus vulgaris shows intraepithelial (suprabasal) blistering with acantholysis; mucous membrane pemphigoid shows subepithelial blistering with an intact basal layer

Pemphigus vulgaris involves autoantibodies against desmoglein 3 (and sometimes desmoglein 1), causing loss of cell-to-cell adhesion (acantholysis) in the suprabasal layer, resulting in intraepithelial blistering. Mucous membrane pemphigoid involves autoantibodies against components of the basement membrane zone (BP180, laminin-332), causing subepithelial blistering with an intact basal layer. Direct immunofluorescence shows intercellular IgG in pemphigus and linear basement membrane IgG/C3 in pemphigoid.

Question 107: In restorative dentistry, the 'biologic width' refers to:

Minimum dentine thickness over pulp
The combined dimension of junctional epithelium and connective tissue attachment (Correct answer)
Root surface area required for osseointegration
Optimal crown length for aesthetics

Correct answer: The combined dimension of junctional epithelium and connective tissue attachment

Biologic width (approximately 2 mm) is the combined height of junctional epithelium (~1 mm) and supracrestal connective tissue (~1 mm); violation by restorative margins causes inflammation and bone loss.

Question 108: Which heat treatment process reduces the brittleness of dental porcelain?

Glazing
Sintering
Degassing
Tempering (Correct answer)

Correct answer: Tempering

Tempering involves controlled cooling that induces surface compressive stresses in porcelain, increasing its resistance to crack propagation and fracture.

Question 109: Glass ionomer cement bonds to tooth structure primarily through:

Micromechanical retention
Ionic bonding to calcium (Correct answer)
Covalent bonding to collagen
Van der Waals forces

Correct answer: Ionic bonding to calcium

Glass ionomer cement forms ionic bonds between carboxylate groups of the polyacid and calcium ions in hydroxyapatite, providing true chemical adhesion.

Question 110: Which bones form the floor of the orbit?

Frontal, zygomatic, and sphenoid bones
Zygomatic, maxillary, and palatine bones (Correct answer)
Maxillary, lacrimal, and ethmoid bones
Zygomatic, frontal, and lacrimal bones

Correct answer: Zygomatic, maxillary, and palatine bones

The floor of the orbit is formed by the orbital surface of the maxilla (largest contribution), the orbital surface of the zygomatic bone (anterolaterally), and the orbital process of the palatine bone (posteriorly).

Question 111: A 28-year-old patient presents with concerns about tooth wear on her upper anterior teeth. On examination, you notice shallow, smooth, scooped-out lesions on the palatal surfaces of the maxillary incisors. Which diagnostic index, specifically recommended in UK guidance for monitoring tooth wear, should be recorded at baseline?

Simplified Oral Hygiene Index (OHI-S)
Lussi Index for Dental Erosion
Tooth Wear Index (TWI) by Smith and Knight
Basic Erosive Wear Examination (BEWE) (Correct answer)

Correct answer: Basic Erosive Wear Examination (BEWE)

The Basic Erosive Wear Examination (BEWE) is a simple and validated tool recommended by UK experts and in guidance documents like 'Delivering Better Oral Health' for screening and monitoring tooth wear, particularly erosive wear. It provides a cumulative score that helps in risk assessment and management planning.

Question 112: Bisphosphonates inhibit bone resorption primarily by targeting:

Fibroblasts
Osteocytes
Osteoclasts (Correct answer)
Osteoblasts

Correct answer: Osteoclasts

Bisphosphonates bind to hydroxyapatite and are taken up by osteoclasts, inhibiting the mevalonate pathway and inducing osteoclast apoptosis.

Question 113: NSAIDs exert their analgesic effect primarily by inhibiting which enzyme?

Cyclooxygenase (COX) (Correct answer)
Lipoxygenase
Phospholipase A2
Thromboxane synthase

Correct answer: Cyclooxygenase (COX)

NSAIDs inhibit cyclooxygenase (COX-1 and COX-2) enzymes, thereby blocking prostaglandin synthesis and reducing pain, inflammation and fever.

Question 114: The pterygomandibular raphe serves as the key landmark for which local anaesthetic technique?

Posterior superior alveolar nerve block
Inferior alveolar nerve block (Correct answer)
Mental nerve block
Infraorbital nerve block

Correct answer: Inferior alveolar nerve block

The pterygomandibular raphe marks the medial boundary of the pterygomandibular space; the needle for an inferior alveolar nerve block is directed lateral to this raphe, towards the mandibular foramen.

Question 115: A patient with a history of asthma experiences an acute asthma attack during dental treatment. What is the appropriate emergency management in the dental surgery?

Lay the patient flat and administer oral prednisolone
Administer intramuscular adrenaline immediately
Sit the patient upright, administer salbutamol 100 mcg via spacer (2-10 puffs), give high-flow oxygen, and call 999 if not responding (Correct answer)
Give intravenous aminophylline and prepare for intubation

Correct answer: Sit the patient upright, administer salbutamol 100 mcg via spacer (2-10 puffs), give high-flow oxygen, and call 999 if not responding

For acute asthma in the dental surgery: sit the patient upright (improves ventilation); administer salbutamol via a metered dose inhaler with a large-volume spacer (2 puffs initially, up to 10 puffs); give high-flow oxygen (15 L/min via face mask); and call 999 if there is no improvement, signs of severe/life-threatening attack (inability to complete sentences, SpO2 <92%, silent chest, cyanosis). Nebulised salbutamol 5 mg should be administered if available.

Question 116: Which nerve provides general somatic sensation to the anterior two-thirds of the tongue?

Glossopharyngeal nerve (CN IX)
Chorda tympani (CN VII)
Lingual nerve (CN V3) (Correct answer)
Hypoglossal nerve (CN XII)

Correct answer: Lingual nerve (CN V3)

The lingual nerve, a branch of the mandibular division of the trigeminal nerve (V3), carries general somatic sensation (touch, pain, temperature) from the anterior two-thirds of the tongue.

Question 117: A patient taking carbamazepine for epilepsy develops a widespread erythematous rash with targetoid lesions, oral ulceration, and conjunctivitis. What is the most likely diagnosis?

Allergic contact dermatitis
Drug-induced lupus erythematosus
Viral exanthem
Erythema multiforme / Stevens-Johnson syndrome (Correct answer)

Correct answer: Erythema multiforme / Stevens-Johnson syndrome

Stevens-Johnson syndrome (SJS) is a severe mucocutaneous reaction most commonly triggered by drugs, particularly anticonvulsants (carbamazepine, phenytoin, lamotrigine), sulphonamides, and allopurinol. Features include targetoid skin lesions, oral ulceration with haemorrhagic crusting of the lips, conjunctivitis, and systemic illness. SJS involves less than 10% body surface area detachment; more extensive involvement (>30%) is classified as toxic epidermal necrolysis (TEN). Immediate drug withdrawal and supportive care are essential.

Question 118: Perikymata are surface features found on which dental tissue?

Enamel (Correct answer)
Pulp
Cementum
Dentine

Correct answer: Enamel

Perikymata are the external manifestations of the striae of Retzius, appearing as transverse ridges on the enamel surface.

Question 119: A biopsy from a gingival swelling in a 25-year-old female shows a proliferation of multinucleated giant cells in a vascular stroma. Serum calcium and parathyroid hormone levels are normal. What is the most likely diagnosis?

Peripheral giant cell granuloma (Correct answer)
Osteosarcoma
Brown tumour of hyperparathyroidism
Aneurysmal bone cyst

Correct answer: Peripheral giant cell granuloma

A peripheral giant cell granuloma (PGCG) is a reactive lesion arising exclusively from the gingiva or edentulous alveolar ridge. It contains numerous multinucleated giant cells (osteoclast-like) in a vascular connective tissue stroma with haemosiderin deposits. It is histologically indistinguishable from the central giant cell granuloma and the brown tumour of hyperparathyroidism, hence the importance of checking serum calcium and PTH levels to exclude hyperparathyroidism. Normal biochemistry confirms PGCG.

Question 120: The mechanism of action of chlorhexidine as an antiseptic mouthwash is:

Competitive inhibition of folic acid synthesis
Inhibition of DNA gyrase
Inhibition of cell wall synthesis
Disruption of bacterial cell membranes (Correct answer)

Correct answer: Disruption of bacterial cell membranes

Chlorhexidine is a cationic bisbiguanide that adsorbs onto negatively charged bacterial cell walls, disrupting membrane integrity and causing cytoplasmic precipitation.

Question 121: What is the most appropriate local anaesthetic technique for extraction of a lower first molar in an adult patient?

Infiltration anaesthesia buccally only
Topical anaesthesia applied to the gingiva
Mental nerve block alone
Inferior alveolar nerve block supplemented with long buccal nerve infiltration (Correct answer)

Correct answer: Inferior alveolar nerve block supplemented with long buccal nerve infiltration

The lower first molar is innervated by the inferior alveolar nerve (pulpal and lingual soft tissue) and the long buccal nerve (buccal soft tissue). An inferior alveolar nerve block anaesthetises the tooth and lingual tissues, while a supplementary long buccal infiltration anaesthetises the buccal gingivae. In some patients, articaine infiltration alone may suffice due to its superior bone penetration, but the IANB plus long buccal is the standard technique.

Question 122: A patient with a dental implant complains of redness and swelling of the surrounding mucosa. Probing reveals bleeding on gentle probing and a pocket depth of 5mm. What single additional finding is essential to differentiate a diagnosis of peri-implantitis from peri-implant mucositis according to the 2017 classification?

Patient-reported discomfort around the implant.
A probing depth greater than 6mm.
The presence of suppuration from the peri-implant sulcus.
Radiographic evidence of bone loss beyond initial remodelling. (Correct answer)

Correct answer: Radiographic evidence of bone loss beyond initial remodelling.

According to the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions, the key feature that distinguishes peri-implantitis from peri-implant mucositis is the presence of progressive radiographic bone loss beyond the initial bone remodelling that occurs after implant placement. Peri-implant mucositis is characterised by inflammation (e.g., bleeding on probing) without this progressive bone loss.

Question 123: Which immune deficiency syndrome most significantly predisposes to invasive oral candidiasis?

Chronic granulomatous disease
Common variable immunodeficiency
IgA deficiency
HIV/AIDS (CD4 <200) (Correct answer)

Correct answer: HIV/AIDS (CD4 <200)

Severe CD4 lymphocytopenia in HIV/AIDS (particularly CD4 <200 cells/μL) profoundly impairs cell-mediated immunity, predisposing to invasive and oropharyngeal candidiasis.

Question 124: The nasopalatine nerve enters the hard palate through which foramen?

Mandibular foramen
Greater palatine foramen
Lesser palatine foramen
Incisive foramen (Correct answer)

Correct answer: Incisive foramen

The nasopalatine nerve (from CN V2) descends through the nasopalatine canal and emerges through the incisive foramen in the midline of the anterior hard palate, supplying the mucosa behind the upper incisors.

Question 125: The submandibular duct (Wharton's duct) opens at which structure in the oral cavity?

Retromolar pad posterior to the lower molars
Parotid papilla on the buccal mucosa
Sublingual papilla lateral to the lingual frenulum
Sublingual caruncle adjacent to the lingual frenulum (Correct answer)

Correct answer: Sublingual caruncle adjacent to the lingual frenulum

Wharton's duct opens at the sublingual caruncle (papilla), a small elevation on either side of the lingual frenulum on the floor of the mouth.

Question 126: Which form of aphthous ulceration leaves scarring on healing?

Minor aphthous ulcers
Major aphthous ulcers (Correct answer)
Herpetiform ulcers
All aphthous ulcers

Correct answer: Major aphthous ulcers

Major aphthous ulcers (Sutton's disease) are large, deep and slow-healing ulcers that frequently leave scarring, unlike the minor form which heals without scar.

Question 127: Galvanic corrosion in the mouth most commonly occurs between:

Composite and GIC
Porcelain and metal
Two dissimilar metals in contact (Correct answer)
Enamel and dentine

Correct answer: Two dissimilar metals in contact

Galvanic corrosion occurs when two dissimilar metals are in contact in the presence of saliva as electrolyte, causing the less noble metal to oxidise.

Question 128: A 70-year-old male who wears a complete upper denture presents with erythema confined to the denture-bearing area of the palate. He is otherwise asymptomatic. What is the most likely diagnosis?

Pemphigus vulgaris
Erythematous candidiasis (denture stomatitis) (Correct answer)
Nicotinic stomatitis
Allergic contact stomatitis to denture acrylic

Correct answer: Erythematous candidiasis (denture stomatitis)

Denture stomatitis (chronic erythematous candidiasis) is the most common form of oral candidiasis, classified by Newton into three types: I (pinpoint hyperaemia), II (diffuse erythema of the denture-bearing mucosa), and III (granular/papillary hyperplasia). It is caused by Candida albicans colonising the fitting surface of the denture. Management includes denture hygiene instruction, antifungal treatment (miconazole oral gel or nystatin), and ensuring the denture is removed at night.

Question 129: Erythromycin achieves its antibacterial effect by binding to the:

50S ribosomal subunit (Correct answer)
DNA gyrase
Penicillin-binding protein
30S ribosomal subunit

Correct answer: 50S ribosomal subunit

Erythromycin (and other macrolides) bind to the 50S ribosomal subunit, blocking translocation and inhibiting bacterial protein synthesis.

Question 130: What is the advantage of a cone beam computed tomography (CBCT) scan over conventional two-dimensional radiography in dentistry, and what are its limitations?

CBCT provides three-dimensional imaging allowing assessment of structures in all planes, with higher spatial resolution than medical CT for dental structures; limitations include higher radiation dose than conventional radiographs, limited soft tissue contrast, and motion artefacts (Correct answer)
CBCT only shows soft tissues and cannot image bone or teeth
CBCT uses less radiation than a single periapical radiograph and has no limitations
CBCT is identical to medical CT in all respects

Correct answer: CBCT provides three-dimensional imaging allowing assessment of structures in all planes, with higher spatial resolution than medical CT for dental structures; limitations include higher radiation dose than conventional radiographs, limited soft tissue contrast, and motion artefacts

CBCT uses a cone-shaped X-ray beam rotating once around the patient to acquire volumetric data, which is reconstructed into 3D images viewable in axial, coronal, sagittal, and oblique planes. Advantages include true 3D assessment (no superimposition), high spatial resolution for hard tissues, lower radiation dose than medical CT (though 5-100 times more than a panoramic radiograph). Limitations include higher dose than conventional radiographs (must be justified under IRMER), poor soft tissue contrast (compared to medical CT/MRI), metallic artefacts from restorations, and motion artefacts.

Question 131: A 68-year-old patient is diagnosed with idiopathic trigeminal neuralgia, experiencing severe, lancinating pains in the V2 distribution. According to the National Institute for Health and Care Excellence (NICE) guideline [CG173], which of the following is the recommended first-line pharmacological treatment?

Ibuprofen
Carbamazepine (Correct answer)
Amitriptyline
Gabapentin

Correct answer: Carbamazepine

The NICE clinical guideline [CG173] on 'Neuropathic pain in adults' specifically recommends offering carbamazepine as the initial treatment for trigeminal neuralgia. While other drugs like amitriptyline and gabapentin are used for different neuropathic pain conditions, carbamazepine is the established first-line choice for this diagnosis. Ibuprofen is not effective for neuropathic pain.

Question 132: Articaine differs from other amide local anaesthetics in that it contains:

A piperidine ring
A benzene ring
A thiophene ring (Correct answer)
An ester linkage

Correct answer: A thiophene ring

Articaine uniquely contains a thiophene ring instead of a benzene ring, which increases its lipid solubility and ability to diffuse through bone.

Question 133: The epithelial cell rests of Malassez are remnants of which structure?

Dental lamina
Reduced enamel epithelium
Enamel organ
Hertwig's epithelial root sheath (Correct answer)

Correct answer: Hertwig's epithelial root sheath

After root formation, fragments of Hertwig's epithelial root sheath persist in the periodontal ligament as the epithelial cell rests of Malassez.

Question 134: A biopsy of a palatal swelling reveals a tumour composed of a mixture of epithelial and myoepithelial cells in a chondromyxoid stroma. What is the most likely diagnosis?

Acinic cell carcinoma
Warthin tumour
Mucoepidermoid carcinoma
Pleomorphic adenoma (mixed tumour) (Correct answer)

Correct answer: Pleomorphic adenoma (mixed tumour)

Pleomorphic adenoma is the most common salivary gland tumour, accounting for approximately 60% of all salivary neoplasms. It shows great histological diversity ('pleomorphic') with a mixture of epithelial cells (forming ducts and sheets), myoepithelial cells, and mesenchymal-like stroma (chondroid, myxoid, or fibrous). The palate is the most common intraoral site (minor salivary glands). Despite being benign, it has a tendency to recur if incompletely excised.

Question 135: During extraction of an upper canine, the labial plate of bone fractures and remains attached to the periosteum. What is the most appropriate management?

Remove the bone fragment completely and smooth the remaining bone
Pack the socket with bone wax and leave the fragment in situ
Refer the patient for immediate bone grafting
Leave the bone fragment attached to its periosteal blood supply, reposition it, and suture the soft tissues over it (Correct answer)

Correct answer: Leave the bone fragment attached to its periosteal blood supply, reposition it, and suture the soft tissues over it

When the labial plate fractures but remains attached to the periosteum, the blood supply is maintained. The fragment should be left attached, gently repositioned to its original position, and the soft tissue flap sutured over it. This approach preserves the alveolar bone contour and allows healing. Removing a vascularised fragment unnecessarily creates a bony defect and compromises future prosthetic rehabilitation.

Question 136: Which corticosteroid preparation is most appropriate for topical treatment of oral mucosal lesions?

Betamethasone mouthwash
Clobetasol propionate ointment
All are appropriate depending on severity (Correct answer)
Hydrocortisone pellets

Correct answer: All are appropriate depending on severity

Hydrocortisone pellets suit localised lesions, betamethasone mouthwash is ideal for widespread lesions, and clobetasol is used for severe resistant cases, selected by lesion extent and severity.

Question 137: A patient develops a dry socket (alveolar osteitis) three days after extraction of a lower wisdom tooth. Which of the following best describes the pathogenesis and management?

Allergic reaction to the local anaesthetic requiring antihistamine treatment
Fracture of the alveolar bone during extraction requiring surgical fixation
Bacterial infection of the socket requiring systemic antibiotics and incision and drainage
Premature loss of the blood clot with exposed bone causing severe pain, managed with irrigation and placement of a sedative dressing such as Alvogyl (Correct answer)

Correct answer: Premature loss of the blood clot with exposed bone causing severe pain, managed with irrigation and placement of a sedative dressing such as Alvogyl

Dry socket results from premature lysis of the blood clot, possibly due to excessive fibrinolysis activated by bacterial enzymes. The exposed alveolar bone causes severe, throbbing pain radiating to the ear, with halitosis and a foul taste. Management involves gentle irrigation with warm saline to remove debris and placement of a sedative/antiseptic dressing (e.g., Alvogyl containing butamben, iodoform, and eugenol). Systemic antibiotics are not indicated unless there is spreading infection.

Question 138: The setting reaction of zinc phosphate cement involves:

Free radical initiation
Chelation
Acid-base neutralisation (Correct answer)
Polymerisation

Correct answer: Acid-base neutralisation

Zinc phosphate cement sets via an acid-base reaction between zinc oxide powder and orthophosphoric acid liquid, forming zinc phosphate salt.

Question 139: An electric pulp tester (EPT) primarily tests:

Pulp neural integrity (Correct answer)
Dentinal permeability
Periapical status
Pulp vascularity

Correct answer: Pulp neural integrity

The EPT tests the integrity of A-delta nerve fibres within the pulp by applying an electrical stimulus; a response indicates neural function but does not assess pulp vitality (vascularity).

Question 140: Which muscle of mastication is the most powerful elevator of the mandible?

Lateral pterygoid
Medial pterygoid
Masseter (Correct answer)
Temporalis

Correct answer: Masseter

The masseter is the most powerful elevator of the mandible; it has superficial and deep heads that together generate the greatest occlusal force among the masticatory muscles.

Question 141: What is the predominant inorganic component of enamel?

Tricalcium phosphate
Fluorapatite
Calcium carbonate
Hydroxyapatite (Correct answer)

Correct answer: Hydroxyapatite

Hydroxyapatite [Ca10(PO4)6(OH)2] constitutes approximately 96% of the dry weight of mature enamel.

Question 142: What is the most appropriate management for a displaced and mobile zygomatic arch fracture causing trismus?

Conservative management with soft diet only
Open reduction and internal fixation with titanium plates
Intermaxillary fixation for six weeks
Closed reduction using a Gillies temporal approach with elevation of the depressed fragment (Correct answer)

Correct answer: Closed reduction using a Gillies temporal approach with elevation of the depressed fragment

A displaced zygomatic arch fracture causing trismus (due to impingement on the coronoid process of the mandible) is typically reduced using the Gillies temporal approach. An incision is made behind the hairline in the temporal region, an elevator is passed beneath the temporalis fascia and deep to the arch, and the depressed fragment is lifted outward. This closed technique avoids facial scarring and is effective for isolated arch fractures.

Question 143: The correct isolation method for rubber dam placement on an upper right first premolar is:

Floss ligature only
Wingless clamp on the premolar only (Correct answer)
Winged clamp with punch hole mesial to planned clamp position
Isolation of the full quadrant with a butterfly clamp

Correct answer: Wingless clamp on the premolar only

A wingless (Ivory W8A or similar) clamp seated directly on the premolar is appropriate, providing secure gingivally sealed isolation for endodontic or restorative access.

Question 144: The onset of action of a local anaesthetic is primarily determined by its:

Protein binding
pKa (Correct answer)
Lipid solubility
Molecular weight

Correct answer: pKa

pKa determines onset: drugs with pKa closer to tissue pH (7.4) have a greater proportion in the uncharged (lipid-soluble) form that penetrates nerve membranes, giving faster onset.

Question 145: Which growth factor is most critical for the initiation of tooth development?

EGF
TGF-β1
FGF-8 (Correct answer)
BMP-4

Correct answer: FGF-8

FGF-8 (fibroblast growth factor 8) is expressed in the oral epithelium and is one of the earliest signals initiating tooth development.

Question 146: Osteogenesis imperfecta is associated with which oral condition?

Hypodontia
Taurodontism
Amelogenesis imperfecta
Dentinogenesis imperfecta (Correct answer)

Correct answer: Dentinogenesis imperfecta

Dentinogenesis imperfecta type I occurs in osteogenesis imperfecta due to defective type I collagen, producing opalescent discoloured teeth prone to attrition.

Question 147: Which monomer is the principal component of composite resin matrices?

UDMA
TEGDMA
PMMA
Bis-GMA (Correct answer)

Correct answer: Bis-GMA

Bis-GMA (bisphenol A glycidyl methacrylate) is the foundational dimethacrylate monomer introduced by Bowen that forms the basis of most composite resin matrices.

Question 148: The incremental lines of von Ebner in dentine represent:

Daily growth increments (Correct answer)
Weekly growth increments
Mineralisation fronts
Periods of illness

Correct answer: Daily growth increments

The lines of von Ebner are daily incremental lines in dentine reflecting the circadian rhythm of odontoblast secretion.

Question 149: Hyperthyroidism in a dental patient most relevantly affects dental management by:

Reducing the need for adrenaline precautions
Requiring antibiotic prophylaxis
Necessitating higher doses of LA
Increasing sensitivity to adrenaline and potential for thyroid crisis (Correct answer)

Correct answer: Increasing sensitivity to adrenaline and potential for thyroid crisis

Hyperthyroid patients are very sensitive to catecholamines; adrenaline in LA solutions can precipitate hypertensive crisis or thyroid storm, necessitating cautious use.

Question 150: A dental practice in the UK must register its use of X-ray equipment under IRR17. Which organisation is responsible for handling this registration?

Public Health England (PHE)
Care Quality Commission (CQC)
General Dental Council (GDC)
Health and Safety Executive (HSE) (Correct answer)

Correct answer: Health and Safety Executive (HSE)

The Ionising Radiations Regulations 2017 (IRR17) require any employer working with ionising radiation, including dental X-ray equipment, to register their activities. This registration process is managed by the Health and Safety Executive (HSE).

Question 151: A 68-year-old edentulous patient requires new complete dentures. On examination, the mandibular ridge is severely resorbed, with inadequate height and width, presenting a flat or even concave form. According to the Cawood and Howell classification, which class best describes this clinical presentation?

Class II
Class III
Class IV
Class VI (Correct answer)

Correct answer: Class VI

The Cawood and Howell classification is a widely used system in UK prosthodontics to describe the morphology of the edentulous alveolar ridge. Class VI represents the most severe stage of resorption, described as a depressed ridge form with some basalar process loss, which corresponds to the clinical finding of a flat or concave ridge with inadequate height and width. Class III is a well-rounded ridge, and Class IV is a 'knife-edge' ridge.

Question 152: According to the 'Delivering Better Oral Health' toolkit, a key evidence-based guide for prevention in the UK, which material is recommended as the first choice for fissure sealing permanent molars in children?

Resin-based sealant (Correct answer)
Compomer-based sealant
Polyacid-modified composite resin sealant
Glass-ionomer based sealant

Correct answer: Resin-based sealant

The 'Delivering Better Oral Health' toolkit explicitly recommends resin-based sealants as the first-choice material for fissure sealing permanent molars. This recommendation is based on strong evidence demonstrating their superior long-term retention and effectiveness in preventing dental caries compared to other materials. Glass-ionomer sealants are noted as a useful alternative where moisture control is difficult, but they are not the primary choice.

Question 153: Which drug interaction is most clinically significant when prescribing metronidazole?

Amoxicillin
Alcohol (disulfiram-like reaction) (Correct answer)
Ibuprofen
Paracetamol

Correct answer: Alcohol (disulfiram-like reaction)

Metronidazole inhibits aldehyde dehydrogenase, causing accumulation of acetaldehyde when alcohol is consumed, producing a severe disulfiram-like reaction.

Question 154: A 60-year-old patient with poorly controlled Type 2 diabetes (HbA1c of 9.5% or 80 mmol/mol) presents with severe, generalised periodontitis. What is the primary mechanism by which their systemic condition exacerbates their periodontal disease?

It leads to an altered, hyper-inflammatory host response to periodontal pathogens. (Correct answer)
It reduces the mineral content of alveolar bone, making it more susceptible to resorption.
It causes direct necrosis of the periodontal ligament fibres.
It directly causes xerostomia, leading to increased plaque accumulation.

Correct answer: It leads to an altered, hyper-inflammatory host response to periodontal pathogens.

The link between diabetes and periodontitis is bidirectional. Poorly controlled diabetes leads to an exaggerated or hyper-inflammatory response to the bacterial challenge in the periodontal tissues. This is mediated by factors such as Advanced Glycation End-products (AGEs), which result in increased production of inflammatory mediators and enhanced tissue destruction. While other factors may play a minor role, the altered host inflammatory response is considered the principal mechanism.

Question 155: A 62-year-old patient requests analgesia for acute dental pain. Their medical history includes a peptic ulcer 5 years ago, well-controlled hypertension treated with ramipril, and asthma. Which of the following analgesics is generally contraindicated?

Dihydrocodeine 30mg
Ibuprofen 400mg (Correct answer)
Paracetamol 500mg
Co-codamol 8/500

Correct answer: Ibuprofen 400mg

Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID). NSAIDs are contraindicated in patients with a history of peptic ulceration due to the risk of gastrointestinal bleeding. They can also exacerbate asthma and should be used with caution in patients taking ACE inhibitors like ramipril.

Question 156: Nikolsky's sign is positive in which oral condition?

Oral lichen planus
Geographic tongue
Denture stomatitis
Pemphigus vulgaris (Correct answer)

Correct answer: Pemphigus vulgaris

Nikolsky's sign (extension of a blister with lateral pressure on normal-appearing mucosa) is positive in pemphigus vulgaris due to loss of desmosomal adhesion.

Question 157: Which cardiac condition most significantly increases the risk of prolonged QT syndrome with erythromycin?

Atrial fibrillation
Mitral valve prolapse
Pre-existing QT prolongation or concurrent QT-prolonging drugs (Correct answer)
Left bundle branch block

Correct answer: Pre-existing QT prolongation or concurrent QT-prolonging drugs

Erythromycin prolongs the cardiac QT interval by blocking hERG potassium channels; this risk is greatly amplified in patients with a pre-existing long QT interval or on other QT-prolonging drugs.

Question 158: A dentist is preparing to permanently cement a lithium disilicate onlay. To achieve a strong and durable adhesive bond, what is the mandatory surface pre-treatment for the intaglio (fitting) surface of this specific type of ceramic restoration before applying a silane coupling agent?

Cleaning with a sodium hypochlorite solution.
Etching with 37% phosphoric acid for 60 seconds.
Etching with approximately 5% hydrofluoric acid for 20 seconds. (Correct answer)
Sandblasting with 50-micron aluminium oxide particles.

Correct answer: Etching with approximately 5% hydrofluoric acid for 20 seconds.

Lithium disilicate is a silica-based ceramic. To create the micromechanical retention necessary for a strong adhesive bond, its fitting surface must be etched with hydrofluoric acid (HF). This process selectively dissolves the glassy matrix, creating a porous surface for the resin cement to penetrate. The typical manufacturer's recommendation for lithium disilicate (e.g., IPS e.max) is to use approximately 5% HF for 20 seconds. Phosphoric acid is ineffective, and sandblasting is the primary pre-treatment for zirconia, not lithium disilicate.

Question 159: The functional unit of the periodontium that suspends the tooth in the socket is the:

Cementum
Epithelial attachment
Periodontal ligament (Correct answer)
Alveolar bone proper

Correct answer: Periodontal ligament

The periodontal ligament is the fibrous connective tissue structure running between cementum and alveolar bone that suspends and supports the tooth during function.

Question 160: Which characteristic of zirconia makes it suitable for high-load dental restorations?

Radiolucency
Transformation toughening (Correct answer)
Low thermal expansion
Translucency

Correct answer: Transformation toughening

Zirconia undergoes stress-induced transformation toughening: tetragonal to monoclinic crystal phase transformation at crack tips generates compressive stresses that halt crack propagation.

Question 161: A 68-year-old patient taking apixaban for atrial fibrillation requires a routine extraction of a single molar tooth. According to the Scottish Dental Clinical Effectiveness Programme (SDCEP) guidance, what is the most appropriate management plan?

Proceed with the extraction but advise the patient to miss their morning dose of apixaban on the day of the procedure.
Advise the patient to stop taking apixaban for 48 hours prior to the extraction.
Proceed with the extraction without altering the medication regimen, using local haemostatic measures. (Correct answer)
Refer the patient to a hospital setting for the extraction under specialist care.

Correct answer: Proceed with the extraction without altering the medication regimen, using local haemostatic measures.

SDCEP guidance on managing patients on anticoagulant drugs states that for procedures with a low risk of bleeding, such as a simple extraction, patients taking Direct Oral Anticoagulants (DOACs) like apixaban should not have their medication interrupted. The risk of a thromboembolic event from stopping the medication outweighs the risk of post-operative bleeding, which can be effectively managed with local measures like suturing and packing the socket.

Question 162: Which stage of tooth development is characterised by proliferation of the enamel organ into a cap shape?

Initiation
Bell stage
Bud stage
Cap stage (Correct answer)

Correct answer: Cap stage

During the cap stage the enamel organ expands and differentiates into inner and outer enamel epithelium, stellate reticulum and stratum intermedium.

Question 163: Which lymph nodes receive primary drainage from the tip of the tongue?

Jugulodigastric nodes
Submandibular nodes
Superior deep cervical nodes
Submental nodes (Correct answer)

Correct answer: Submental nodes

The tip of the tongue drains primarily to the submental lymph nodes (between the anterior bellies of the digastric muscles), which then drain to the deep cervical chain.

Question 164: Hertwig's epithelial root sheath is derived from which structure?

Alveolar bone
Dental papilla
Enamel organ (Correct answer)
Dental follicle

Correct answer: Enamel organ

Hertwig's epithelial root sheath forms from the fusion of the inner and outer enamel epithelium at the cervical loop of the enamel organ.

Question 165: Which component of traditional Mineral Trioxide Aggregate (MTA) formulations is primarily responsible for the potential greyish discolouration of tooth structure, particularly when it interacts with common endodontic irrigants like sodium hypochlorite?

Bismuth oxide (Correct answer)
Calcium sulphate
Tricalcium silicate
Dicalcium phosphate

Correct answer: Bismuth oxide

Bismuth oxide is added to MTA as a radiopacifier. However, it has been widely shown to be the primary cause of tooth discolouration. This staining can be exacerbated when bismuth oxide interacts with sodium hypochlorite, a common root canal irrigant, or with blood, leading to the formation of a dark precipitate that can leach into the dentinal tubules.

Question 166: A dentist is planning a post-retained crown for a root-canal-treated upper central incisor. To maximise the fracture resistance of the final restoration, what is the minimum recommended height of circumferential coronal tooth structure (ferrule) that should be preserved above the crown margin?

0.5 mm
1.0 mm
1.5 - 2.0 mm (Correct answer)
3.0 mm

Correct answer: 1.5 - 2.0 mm

The ferrule effect is a crucial principle in prosthodontics for improving the longevity of post-retained crowns. A circumferential band of healthy tooth structure is required to resist functional lever forces and reduce stress concentration. UK and international guidelines consistently recommend a minimum ferrule height of 1.5 to 2.0 mm to significantly enhance the fracture resistance of the restored tooth.

Question 167: Sickle cell anaemia patients face which specific risk during general anaesthesia?

Malignant hyperthermia
Sickling crisis triggered by hypoxia, dehydration or hypothermia (Correct answer)
Prolonged neuromuscular blockade
Pseudocholinesterase deficiency

Correct answer: Sickling crisis triggered by hypoxia, dehydration or hypothermia

Hypoxia, dehydration and hypothermia can trigger a sickling crisis in HbS patients; careful perioperative management is essential including optimal oxygenation and hydration.

Question 168: Which type of gypsum product has the highest compressive strength?

Die stone (Type IV) (Correct answer)
Plaster of Paris (Type II)
Dental stone (Type III)
Orthodontic plaster (Type I)

Correct answer: Die stone (Type IV)

Type IV die stone (high-strength dental stone) has the highest compressive strength due to the regular particle shape resulting from autoclaving.

Question 169: Mikulicz cells, which are large macrophages containing the causative organism, are found in:

Tuberculosis
Actinomycosis
Rhinoscleroma (Correct answer)
Noma

Correct answer: Rhinoscleroma

Rhinoscleroma (caused by Klebsiella rhinoscleromatis) is characterised by large vacuolated macrophages called Mikulicz cells containing the organisms.

Question 170: Which type of cementum covers the apical third of the root and contains cells?

Acellular extrinsic fibre cementum
Cellular mixed stratified cementum (Correct answer)
Cellular intrinsic fibre cementum
Acellular afibrillar cementum

Correct answer: Cellular mixed stratified cementum

Cellular mixed stratified cementum is found predominantly at the apical third and furcation areas and contains cementocytes entrapped during rapid deposition.

Question 171: A patient in England is dissatisfied with the outcome of their NHS dental treatment. Having exhausted the practice's in-house complaints procedure without resolution, which independent body should the patient be advised to contact next to escalate their complaint?

The Parliamentary and Health Service Ombudsman (PHSO). (Correct answer)
The General Dental Council (GDC).
The Dental Complaints Service (DCS).
The Care Quality Commission (CQC).

Correct answer: The Parliamentary and Health Service Ombudsman (PHSO).

The NHS complaints procedure in England has two main stages. After local resolution with the practice fails, the complaint can be escalated to the Parliamentary and Health Service Ombudsman (PHSO). [5, 17, 27] The PHSO makes the final decision on unresolved complaints about the NHS in England. [5, 27] The GDC investigates fitness to practise, not patient redress; the CQC regulates services but doesn't handle individual complaints; and the Dental Complaints Service (DCS) is for private dental treatment. [10, 27]

Question 172: A conscious and coherent patient with type 1 diabetes reports feeling shaky, sweaty, and confused during their appointment. A capillary blood glucose test confirms a reading of 3.2 mmol/L. What is the most appropriate initial management step?

Administer 1 mg of glucagon via intramuscular injection.
Provide 15-20g of a fast-acting carbohydrate, such as a glucose drink or tablets. (Correct answer)
Call 999 for an ambulance immediately.
Administer the patient's own insulin.

Correct answer: Provide 15-20g of a fast-acting carbohydrate, such as a glucose drink or tablets.

The patient is conscious and able to swallow, presenting with symptomatic hypoglycaemia (blood glucose <4.0 mmol/L). UK guidelines recommend the immediate administration of 15-20g of a fast-acting oral carbohydrate. Glucagon injection is reserved for patients who are unconscious or unable to swallow safely. Administering insulin would lower blood glucose further and be extremely dangerous. Calling 999 is not the initial step for a conscious patient who can be managed with oral glucose.

Question 173: The most common type of odontogenic cyst is the:

Odontogenic keratocyst
Dentigerous cyst
Radicular cyst (Correct answer)
Lateral periodontal cyst

Correct answer: Radicular cyst

Radicular cysts (periapical cysts) are the most common odontogenic cysts, arising from proliferation of the epithelial cell rests of Malassez in response to periapical inflammation.

Question 174: Prednisolone, a synthetic glucocorticoid, suppresses inflammation primarily by:

Inhibiting COX-2 directly
Activating mast cell degranulation
Inducing lipocortin which inhibits phospholipase A2 (Correct answer)
Blocking histamine receptors

Correct answer: Inducing lipocortin which inhibits phospholipase A2

Glucocorticoids induce synthesis of annexin-1 (lipocortin), which inhibits phospholipase A2, blocking arachidonic acid release and thus the entire downstream inflammatory cascade.

Question 175: Which component of saliva provides the primary antimicrobial defence against oral bacteria?

Lactoferrin
Amylase
Secretory IgA (Correct answer)
Mucin

Correct answer: Secretory IgA

Secretory IgA is the predominant immunoglobulin in saliva and acts by aggregating bacteria and blocking their adhesion to oral surfaces.

Question 176: A dentist explains the procedure for placing a crown but only mentions common risks like temporary sensitivity. The patient later suffers from irreversible pulpitis, a rare but serious complication that was not discussed. According to the principles established by the UK Supreme Court in Montgomery v Lanarkshire Health Board, has the dentist obtained valid consent?

No, because the dentist failed to disclose a material risk that a reasonable person in the patient's position would likely attach significance to. (Correct answer)
Yes, because the risk of irreversible pulpitis was too rare to be considered a mandatory disclosure.
No, because all possible risks, however minor or rare, must be disclosed for consent to be valid.
Yes, because the dentist acted in line with what a responsible body of dentists would have disclosed (the Bolam test).

Correct answer: No, because the dentist failed to disclose a material risk that a reasonable person in the patient's position would likely attach significance to.

The *Montgomery* ruling shifted the standard for consent from the professional-focused 'Bolam test' to a patient-centric model. [3, 12, 18] For consent to be valid, a dentist must take reasonable care to ensure the patient is aware of any material risks and of reasonable alternatives. A risk is 'material' if a reasonable person in the patient's position would likely attach significance to it, or if the practitioner knows (or should know) that this particular patient would attach significance to it. [3, 34] A rare but serious risk like irreversible pulpitis would likely be considered material by a patient, and therefore failure to discuss it invalidates consent.

Question 177: An inferior alveolar nerve block fails to anaesthetise which structure, necessitating a separate injection?

Mandibular premolar pulps
Mandibular molars pulps
Buccal gingiva of mandibular molars (Correct answer)
Lower lip and chin

Correct answer: Buccal gingiva of mandibular molars

The buccal (long buccal) nerve, a separate branch of CN V3, supplies the buccal gingiva and mucosa of the mandibular molar region and is not blocked by a standard inferior alveolar nerve block.

Question 178: A patient presents with a painful, solitary ulcer on the lateral border of the tongue that has been present for three weeks. There is no obvious local cause. What is the most important next step?

Reassure the patient and advise warm salt water rinses
Prescribe a topical corticosteroid and review in one week
Arrange an urgent two-week-wait referral for biopsy to exclude malignancy (Correct answer)
Prescribe antibiotics and review in two weeks

Correct answer: Arrange an urgent two-week-wait referral for biopsy to exclude malignancy

A solitary ulcer on the lateral border of the tongue persisting for more than three weeks without an identifiable local cause (such as a sharp tooth or denture) requires urgent investigation to exclude squamous cell carcinoma. Under NICE guidelines, this warrants a two-week-wait urgent referral. The lateral border of the tongue is the most common intraoral site for oral squamous cell carcinoma.

Question 179: The Twin Block appliance is a widely used functional appliance in the UK for the correction of Class II division 1 malocclusions. What is its primary mode of action in correcting the skeletal and dental relationship?

By encouraging mandibular growth and causing dentoalveolar changes. (Correct answer)
By expanding the maxilla and distalising the maxillary molars.
By causing proclination of the lower incisors only.
By applying extra-oral force to restrain maxillary growth.

Correct answer: By encouraging mandibular growth and causing dentoalveolar changes.

The Twin Block appliance holds the mandible in a protruded position. This posture is thought to stimulate condylar growth, encouraging the mandible to grow to its full potential. Concurrently, it produces significant dentoalveolar changes, including retroclination of upper incisors and proclination of lower incisors, which contribute to overjet reduction. The overall effect is a combination of skeletal and dental modifications.

Question 180: Which hepatitis virus is most commonly transmitted through needlestick injuries in dental practice, and what is the post-exposure prophylaxis protocol?

Hepatitis C — immediate interferon treatment
Hepatitis E — oral ribavirin prophylaxis
Hepatitis B — post-exposure prophylaxis includes hepatitis B immunoglobulin (HBIG) and/or accelerated hepatitis B vaccination course if the recipient is not immune (Correct answer)
Hepatitis A — no prophylaxis needed

Correct answer: Hepatitis B — post-exposure prophylaxis includes hepatitis B immunoglobulin (HBIG) and/or accelerated hepatitis B vaccination course if the recipient is not immune

Hepatitis B virus (HBV) is the most transmissible bloodborne virus through needlestick injury, with a transmission rate of approximately 6-30% from HBeAg-positive sources (compared to 1.8% for HCV and 0.3% for HIV). Post-exposure management includes immediate wound care, risk assessment, and for non-immune recipients: hepatitis B immunoglobulin (HBIG) ideally within 48 hours plus an accelerated vaccination course. All dental healthcare workers should be vaccinated and have confirmed immunity (anti-HBs ≥10 mIU/mL).

MFDS Part 1 Exam

The MFDS Part 1 exam, jointly administered by the Royal College of Surgeons of Edinburgh (RCSEd) and RCPSG, is a three-hour written assessment comprising 180 Single Best Answer (SBA) questions. It tests the breadth of dental knowledge required for direct patient care, including basic sciences, clinical dental sciences, human disease, pharmacology, dental materials, and radiology. The pass mark is determined by the Angoff method on a per-sitting basis.

180

Questions

180 min

Time Limit

65%

To Pass

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