MFDS Part 1 Exam — Questions and Answers

Question 1: The polymerisation shrinkage of conventional composite resins is approximately:

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

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 2: The ideal occlusal scheme for a full arch implant-retained prosthesis is:

Group function
Canine guidance only
Lingualized occlusion
Mutually protected occlusion (Correct answer)

Correct answer: Mutually protected occlusion

Mutually protected occlusion (anterior guidance protects posteriors in excursions; posteriors protect anteriors in ICP load) is the preferred scheme for implant-supported prostheses to minimise lateral forces on implants.

Question 3: Which liver disease most significantly impairs drug metabolism in dental practice?

Non-alcoholic fatty liver disease
Primary biliary cholangitis (early stage)
Severe cirrhosis (Correct answer)
Hepatitis A (acute)

Correct answer: Severe cirrhosis

Severe cirrhosis markedly reduces hepatic drug-metabolising capacity (cytochrome P450 activity) and can impair clotting factor synthesis, both clinically relevant in dental prescribing.

Question 4: The incremental lines of von Ebner in dentine represent:

Mineralisation fronts
Daily growth increments (Correct answer)
Weekly growth increments
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 5: Which stage of tooth development is characterised by proliferation of the enamel organ into a cap shape?

Bud stage
Cap stage (Correct answer)
Initiation
Bell stage

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

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
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)

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 7: 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 approximately 5% hydrofluoric acid for 20 seconds. (Correct answer)
Etching with 37% phosphoric acid for 60 seconds.
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 8: Which cranial nerve exits the skull through the stylomastoid foramen?

Facial nerve (CN VII) (Correct answer)
Glossopharyngeal nerve (CN IX)
Accessory nerve (CN XI)
Hypoglossal nerve (CN XII)

Correct answer: Facial nerve (CN VII)

The facial nerve (CN VII) exits the skull through the stylomastoid foramen before entering the parotid gland, where it divides into its five terminal branches (temporal, zygomatic, buccal, marginal mandibular, cervical).

Question 9: 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 Dental Complaints Service (DCS).
The Parliamentary and Health Service Ombudsman (PHSO). (Correct answer)
The General Dental Council (GDC).
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 10: A 55-year-old male patient attends for a routine examination. During the social history, he mentions he regularly drinks a large bottle of wine over two evenings. According to the 'Delivering Better Oral Health' toolkit, which of the following is the most appropriate initial screening tool to assess his level of risk from alcohol harm?

FAST (Fast Alcohol Screening Test)
SAD-Q (Severity of Alcohol Dependence Questionnaire)
AUDIT-C (Alcohol Use Disorders Identification Test - Consumption) (Correct answer)
CAGE questionnaire

Correct answer: AUDIT-C (Alcohol Use Disorders Identification Test - Consumption)

The 'Delivering Better Oral Health' toolkit, an evidence-based guide for dental teams in the UK, recommends using the AUDIT-C tool to assess a patient's level of risk of alcohol harm. It consists of three consumption questions and is a brief, effective screening method suitable for a primary care setting like dentistry.

Question 11: What is the predominant inorganic component of enamel?

Hydroxyapatite (Correct answer)
Calcium carbonate
Tricalcium phosphate
Fluorapatite

Correct answer: Hydroxyapatite

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

Question 12: 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 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 result is within the pre-diabetic range and has no relevance to dental treatment
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 13: What does the term 'thixotropic' mean when applied to impression materials?

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

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

Patient-centred care (Correct answer)
Candour
Confidentiality
Beneficence

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

Odontoclasts (Correct answer)
Osteoblasts
Fibroblasts
Cementoblasts

Correct answer: Odontoclasts

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

Question 16: What are the boundaries of the 'anatomical snuffbox' and which artery is at risk during surgical procedures in this region?

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
Bounded by the buccinator and orbicularis oris; the buccal artery is at risk
Bounded by the tendons of abductor pollicis longus/extensor pollicis brevis and extensor pollicis longus; the radial artery passes through its floor (Correct answer)

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 17: 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 lichen planus (Correct answer)
Candidiasis
Oral leukoplakia

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 18: 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)
Paracetamol is contraindicated; use ibuprofen instead
Codeine is contraindicated; use diclofenac instead
All analgesics are safe in renal impairment

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

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 20: The maximum recommended dose of lidocaine with adrenaline for a healthy adult is approximately:

10 mg/kg (max 700 mg)
7 mg/kg (max 500 mg) (Correct answer)
3 mg/kg (max 200 mg)
2 mg/kg (max 100 mg)

Correct answer: 7 mg/kg (max 500 mg)

Lidocaine with adrenaline (epinephrine) has a maximum recommended dose of 7 mg/kg up to 500 mg in healthy adults, higher than plain lidocaine due to vasoconstriction.

Question 21: 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?

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

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 22: Under the Ionising Radiations Regulations 2017 (IRR17), which of the following is a primary responsibility of the appointed Radiation Protection Supervisor (RPS) within a dental practice?

To provide detailed advice on the design of new dental facilities.
To conduct critical examinations of new X-ray equipment.
To carry out the justification and authorisation of all medical exposures.
To ensure compliance with the Local Rules on a day-to-day basis. (Correct answer)

Correct answer: To ensure compliance with the Local Rules on a day-to-day basis.

The RPS is appointed by the employer to supervise the work and ensure that the Local Rules are being followed by all staff. The Radiation Protection Adviser (RPA) provides advice on facility design and regulatory compliance, while the critical examination is performed by the installer/manufacturer. Justification is the role of the IRMER Practitioner.

Question 23: A 5-year-old child attends for their first dental examination and is visibly anxious. According to standard UK practice, which of the following non-pharmacological behaviour management techniques should be employed first to introduce the child to the clinical environment and instruments?

Tell-Show-Do (Correct answer)
Hand-over-mouth exercise (HOME)
Negative reinforcement
Voice control

Correct answer: Tell-Show-Do

Tell-Show-Do is a fundamental and widely accepted technique in paediatric dentistry for introducing a new or potentially anxiety-provoking procedure. It involves explaining the procedure in simple terms (Tell), demonstrating it, for example on a model or the clinician's finger (Show), and then performing it on the child (Do). This technique builds trust and desensitises the child. Voice control is a component of communication, but not a standalone introductory technique. Negative reinforcement and HOME are considered outdated and inappropriate techniques in modern UK paediatric dentistry.

Question 24: 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?

Refer the patient to a hospital setting for the extraction under specialist care.
Proceed with the extraction without altering the medication regimen, using local haemostatic measures. (Correct answer)
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.

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 25: 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 selective-enamel etch technique followed by application of a one-step self-etch adhesive.
A three-step total-etch (etch-and-rinse) adhesive system.
A one-step self-etch adhesive system applied in a single layer.

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

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

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 27: 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 28: A 48-year-old female presents with asymptomatic, bilateral, symmetrical, white, lace-like striations on her buccal mucosa. The lesions are non-wipeable. What is the most likely diagnosis?

Pseudomembranous candidiasis
Frictional keratosis
Leukoplakia
Oral Lichen Planus (Correct answer)

Correct answer: Oral Lichen Planus

The clinical description of bilateral, asymptomatic, white, reticular (lace-like) patterns (Wickham's striae) on the buccal mucosa is the classic presentation of reticular oral lichen planus. Leukoplakia is typically a more homogenous patch and often unilateral, candidiasis can be wiped off, and frictional keratosis would correspond to an area of trauma.

Question 29: What is the significance of an INR result for a patient taking warfarin, and what is the generally accepted safe range for dental extractions?

INR is only relevant for patients on heparin, not warfarin
INR measures liver function; no range is relevant for dentistry
INR must be below 1.0 for any dental procedure
INR measures the degree of anticoagulation; dental extractions can generally be performed safely if the INR is 4.0 or below, with local haemostatic measures (Correct answer)

Correct answer: INR measures the degree of anticoagulation; dental extractions can generally be performed safely if the INR is 4.0 or below, with local haemostatic measures

The INR (International Normalised Ratio) measures the degree of anticoagulation with warfarin, with a normal value of approximately 1.0. For dental extractions, current UK guidelines recommend that procedures can be performed in primary care if the INR is stable and ≤4.0, checked within 24-72 hours before the procedure. Local haemostatic measures (suturing, oxidised cellulose, tranexamic acid mouthwash) should be used. Warfarin should NOT be stopped or reduced for dental procedures due to thromboembolic risk.

Question 30: 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?

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

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

Mental nerve
Inferior alveolar nerve (Correct answer)
Buccal 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 32: An electric pulp tester (EPT) primarily tests:

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

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 33: 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?

The patient is asymptomatic but the tooth is horizontally impacted.
To prevent potential future crowding of the anterior teeth.
A single, mild episode of pericoronitis that resolved with local measures.
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 34: Which muscle of mastication is the most powerful elevator of the mandible?

Medial pterygoid
Masseter (Correct answer)
Lateral pterygoid
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 35: 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
An oral irrigator
Dental floss
Interdental brushes (Correct answer)

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 36: A patient presents for emergency dental treatment and reports taking clopidogrel and aspirin (dual antiplatelet therapy) following coronary stent insertion six months ago. How should this be managed?

Stop aspirin but continue clopidogrel
Stop both drugs 7 days before extraction
Do NOT stop either drug — perform the extraction with local haemostatic measures such as suturing, oxidised cellulose, and tranexamic acid mouthwash (Correct answer)
Postpone all dental treatment until the antiplatelet therapy is completed

Correct answer: Do NOT stop either drug — perform the extraction with local haemostatic measures such as suturing, oxidised cellulose, and tranexamic acid mouthwash

Current guidelines recommend NOT stopping dual antiplatelet therapy for dental extractions due to the risk of stent thrombosis, which carries a mortality rate of up to 40%. Local haemostatic measures are sufficient to manage post-extraction bleeding: suturing, oxidised cellulose (Surgicel) or collagen sponge in the socket, and tranexamic acid 5% mouthwash (held for 2 minutes, four times daily for 2 days). The bleeding risk from dental procedures on antiplatelet therapy is low and manageable.

Question 37: Which nerve is most commonly damaged during a sagittal split osteotomy of the mandible, and what are the typical symptoms?

The facial nerve, causing motor paralysis of the lower lip
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 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 38: 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?

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

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 39: 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?

Dentigerous (follicular) cyst (Correct answer)
Stafne bone cavity
Ameloblastoma
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 40: 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)
Treat the child's dental needs and schedule a review in one month to monitor the situation.
Immediately telephone the police to report a case of child abuse.
Confront the parent directly about the suspicion of non-accidental injury.

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 41: 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?

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

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

Radiolucency
Transformation toughening (Correct answer)
Translucency
Low thermal expansion

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

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

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 44: Dead tracts in dentine are caused by:

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

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

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

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

Chorda tympani (CN VII)
Lingual nerve (CN V3) (Correct answer)
Glossopharyngeal nerve (CN IX)
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 47: Sickle cell anaemia patients face which specific risk during general anaesthesia?

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

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 48: Tetracyclines are contraindicated in children under 12 years because they:

Cause nephrotoxicity
Bind to calcium in developing teeth causing staining (Correct answer)
Suppress bone marrow
Cross the blood-brain barrier

Correct answer: Bind to calcium in developing teeth causing staining

Tetracyclines chelate calcium and are deposited in developing mineralised tissues, causing permanent yellow-brown staining and hypoplasia of teeth and bones.

Question 49: Which antibiotic is first-line for odontogenic infections in penicillin-allergic patients?

Clindamycin (Correct answer)
Ciprofloxacin
Metronidazole
Erythromycin

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 50: 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 approximately 1 millisievert, equivalent to a full mouth series
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 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 51: Hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu disease) presents with oral telangiectases and:

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

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 52: 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 2: Communicate effectively with patients.
Principle 8: Raise concerns if patients are at risk.
Principle 6: Work with colleagues in a way that is in patients' best interests.
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 53: 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 54: The most common site for oral squamous cell carcinoma in the UK is the:

Gingiva
Floor of mouth and lateral tongue (Correct answer)
Hard palate
Buccal mucosa

Correct answer: Floor of mouth and lateral tongue

The floor of mouth and lateral/ventral tongue represent the highest-risk sites for oral squamous cell carcinoma in the UK population.

Question 55: 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?

Persistent soft tissue pressures (e.g., tongue thrust).
Contraction of the supracrestal gingival fibres.
Inherent memory of the periodontal ligament fibres.
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 56: Which type of tooth movement is most energy-efficient and causes the least root resorption in orthodontics?

Tipping (Correct answer)
Torque
Extrusion
Bodily movement

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 57: A 50-year-old patient complains of a sharp, intermittent pain on biting on their lower right first molar (LR6), which has a large MOD amalgam restoration. The pain disappears immediately on release. There is no lingering pain to thermal stimuli and no periapical pathology is evident on the radiograph. Transillumination reveals a crack line extending from the mesial marginal ridge. What is the most appropriate immediate management to prevent crack propagation?

Place the tooth on a watch-and-wait protocol
Immediate root canal treatment
Extraction of the tooth
Placement of a full-coverage cuspal protection restoration (e.g., a crown) (Correct answer)

Correct answer: Placement of a full-coverage cuspal protection restoration (e.g., a crown)

The symptoms are classic for 'cracked tooth syndrome'. The immediate priority is to stabilise the tooth and prevent the crack from propagating, which could lead to pulpal involvement or a vertical root fracture. The most effective way to achieve this is by placing a restoration that provides cuspal coverage, such as a crown or a protective orthodontic band. This braces the tooth structure together, distributing occlusal forces and alleviating the symptoms. Root canal treatment is only indicated if the pulp becomes irreversibly inflamed or necrotic.

Question 58: The mechanism of action of chlorhexidine as an antiseptic mouthwash is:

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

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

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

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 60: A patient presents with vesicles and ulcers on the palate and gingiva, preceded by prodromal tingling. Culture confirms herpes simplex virus type 1 (HSV-1). This is the patient's third episode in six months. What is the most appropriate management?

No treatment is needed as recurrent herpes is self-limiting
Prescribe systemic fluconazole 50 mg daily
Prescribe topical corticosteroids to reduce inflammation
Prescribe systemic aciclovir 200 mg five times daily for 5 days for each episode and consider prophylactic aciclovir 400 mg twice daily if recurrences continue (Correct answer)

Correct answer: Prescribe systemic aciclovir 200 mg five times daily for 5 days for each episode and consider prophylactic aciclovir 400 mg twice daily if recurrences continue

Recurrent intraoral herpes in immunocompetent patients is managed with systemic aciclovir 200 mg five times daily for 5 days, started within 48 hours of symptom onset. For frequent recurrences (6 or more per year), prophylactic aciclovir 400 mg twice daily can be considered for 6-12 months. Topical aciclovir is ineffective for intraoral lesions. Corticosteroids are contraindicated as they may worsen viral infections.

Question 61: What is the approximate pH at which enamel begins to demineralise?

7.0
4.0
6.2
5.5 (Correct answer)

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 62: When planning a full coverage crown for a root-filled molar, which of the following factors is considered most critical for the long-term prognosis and fracture resistance of the tooth?

The presence of a circumferential ferrule of 1.5-2.0 mm of sound tooth structure. (Correct answer)
The type of luting cement used for the crown.
The use of a resin-modified glass ionomer core material.
The length and diameter of the post placed within the root canal.

Correct answer: The presence of a circumferential ferrule of 1.5-2.0 mm of sound tooth structure.

The ferrule effect, which is a 360-degree collar of sound tooth structure coronal to the crown margin, is widely regarded as the most important determinant for the fracture resistance of a restored, root-filled tooth. A ferrule of at least 1.5-2.0 mm in height braces the tooth against functional forces, reducing stress on the post and within the root, thereby significantly improving the long-term prognosis. While other factors are important, the presence of an adequate ferrule is the most critical.

Question 63: Which classification is used to grade epithelial dysplasia in oral precancerous lesions?

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

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 64: Which bonding agent generation first introduced self-etching primers to eliminate the separate acid-etch step?

6th generation (Correct answer)
3rd generation
4th generation
5th generation

Correct answer: 6th generation

6th generation adhesives introduced self-etching primers that simultaneously condition and prime without a separate phosphoric acid etch step.

Question 65: What is the most appropriate management for a displaced and mobile zygomatic arch fracture causing trismus?

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)
Conservative management with soft diet only

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 66: A 7-year-old child, assessed as having a high risk of developing caries, attends for an examination. Her primary molars are in contact, preventing visual inspection of the interproximal surfaces. In line with the Faculty of General Dental Practice (UK) 'Selection Criteria for Dental Radiography', what is the recommended maximum interval for taking posterior bitewing radiographs for this child?

Only when symptoms arise.
Every 24 months.
Every 6 months. (Correct answer)
Every 12 months.

Correct answer: Every 6 months.

The FGDP (UK) guidelines recommend that for children assessed as being at high risk of caries, posterior bitewing radiographs should be taken at 6-monthly intervals once posterior contacts are closed. This increased frequency is justified by the need for early detection of lesions in patients who are more susceptible to rapid caries progression. For low-risk children, the interval can be extended to 12-24 months.

Question 67: 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?

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

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 68: Which salivary gland produces the most serous secretion relative to its total output?

Submandibular
Parotid (Correct answer)
Sublingual
Minor labial glands

Correct answer: Parotid

The parotid gland is purely serous and contributes approximately 25% of total salivary volume but nearly all the amylase-rich serous component.

Question 69: 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 relies solely on mechanical undercuts in the cavity preparation for retention.
It forms a micromechanical bond via a resin-infiltrated hybrid layer.
It requires a separate phosphoric acid etchant and a bonding agent to adhere.
It sets via an acid-base reaction and forms a true chemical bond through ionic exchange. (Correct answer)

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 70: Verrucous carcinoma differs from conventional SCC in that it:

Has a pushing border and low-grade histology (Correct answer)
Is HPV negative always
Requires immediate radical surgery
Metastasises early

Correct answer: Has a pushing border and low-grade histology

Verrucous carcinoma is a low-grade variant of SCC with a pushing (non-infiltrative) border, minimal cytological atypia and an excellent prognosis with complete excision.

Question 71: 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 72: The parotid duct (Stensen's duct) opens into the oral vestibule opposite which tooth?

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

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

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

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 74: 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?

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

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 75: A healthy 4-year-old child weighing 18kg requires post-operative analgesia following a dental extraction. According to the British National Formulary for Children (BNFC), what is the appropriate single oral dose of paracetamol for this child?

270 mg (Correct answer)
500 mg
120 mg
180 mg

Correct answer: 270 mg

The British National Formulary for Children (BNFC) recommends a standard oral paracetamol dose of 15 mg per kg of body weight for children aged 1 month to 18 years, administered every 4-6 hours (maximum 4 doses in 24 hours). For an 18 kg child, the calculation is 18 kg x 15 mg/kg = 270 mg.

Question 76: 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.
Keeping the periosteal elevator in constant, firm contact with the lingual plate of bone during elevation. (Correct answer)
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.

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 77: The setting reaction of zinc phosphate cement involves:

Chelation
Acid-base neutralisation (Correct answer)
Free radical initiation
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 78: A patient presents with multiple jaw cysts. Genetic testing reveals a mutation in the PTCH1 gene. What syndrome is this patient likely to have?

Gardner syndrome
Gorlin-Goltz syndrome (naevoid basal cell carcinoma syndrome) (Correct answer)
McCune-Albright syndrome
Peutz-Jeghers 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 79: Which of the following conditions is MOST commonly associated with a geographic tongue (erythema migrans)?

HIV infection
Oral cancer
Diabetes mellitus
Psoriasis (Correct answer)

Correct answer: Psoriasis

Geographic tongue (erythema migrans/benign migratory glossitis) shows a strong association with psoriasis, and some authorities consider it an oral manifestation of psoriasis. Both conditions share histopathological similarities including spongiform pustulation. Other associations include fissured tongue and atopy. Geographic tongue is benign, affecting 1-3% of the population, and is characterised by migratory areas of depapillation with raised white borders.

Question 80: 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?

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

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

All Lateral And Rotational Adjustments — it refers to patient positioning
It refers to the storage protocol for radiographic films
Anterior Lateral Anteroposterior Radiograph Assessment — a specific projection technique
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)

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 82: A 45-year-old patient on long-term bisphosphonate therapy for osteoporosis requires extraction of a non-restorable lower molar. What is the primary concern and how should it be managed?

Risk of medication-related osteonecrosis of the jaw (MRONJ) — assess risk factors, consider antibiotic prophylaxis, perform atraumatic extraction, and achieve primary closure (Correct answer)
Risk of anaphylaxis to the bisphosphonate — have adrenaline available
No additional concerns — proceed with routine extraction
Risk of excessive bleeding — obtain a coagulation screen first

Correct answer: Risk of medication-related osteonecrosis of the jaw (MRONJ) — assess risk factors, consider antibiotic prophylaxis, perform atraumatic extraction, and achieve primary closure

Bisphosphonates inhibit osteoclast activity and reduce bone turnover, increasing the risk of medication-related osteonecrosis of the jaw (MRONJ) following invasive dental procedures. Management includes assessing the patient's MRONJ risk (duration and route of bisphosphonate therapy, other risk factors), providing prophylactic antibiotics, performing the extraction as atraumatically as possible, achieving primary soft tissue closure, and close follow-up monitoring.

Question 83: 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 cause severe hypertension when combined with adrenaline-containing local anaesthetics
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)
SSRIs potentiate the effect of local anaesthetics, causing prolonged numbness
SSRIs have no clinically significant interactions relevant to dentistry

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 84: Cotton wool appearance on radiographs is characteristic of which condition?

Paget's disease of bone (Correct answer)
Osteosarcoma
Fibrous dysplasia
Multiple myeloma

Correct answer: Paget's disease of bone

Paget's disease in the remodelling (mixed) phase produces a characteristic 'cotton wool' or 'ground glass' radiographic appearance due to disorganised woven bone formation.

Question 85: 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?

Provide 15-20g of a fast-acting carbohydrate, such as a glucose drink or tablets. (Correct answer)
Administer 1 mg of glucagon via intramuscular injection.
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 86: 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.
Immediate extraction to prevent damage to the permanent tooth.
Prescription of systemic antibiotics and active surveillance.
Advise the parent to monitor for spontaneous re-eruption. (Correct answer)

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 87: Florid cemento-osseous dysplasia most commonly affects which demographic group?

Young white males
Middle-aged black women (Correct answer)
Elderly Asian men
Adolescent females of any ethnicity

Correct answer: Middle-aged black women

Florid cemento-osseous dysplasia has a strong predilection for middle-aged black women and is typically an incidental radiographic finding requiring no treatment.

Question 88: 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?

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

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

Pterygomandibular space (Correct answer)
Buccal space
Parapharyngeal space
Temporal 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 90: 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?

Within the first week of life
18 months
12 months
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 91: 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?

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

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 92: 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 93: The submandibular duct (Wharton's duct) opens at which structure in the oral cavity?

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

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

Ciliated columnar epithelium resembling respiratory mucosa
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)
Thick, non-keratinised epithelial lining with rete ridges
Mucous-secreting epithelium with goblet cells

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 95: Which property is most important when selecting a luting cement for a post with a long, parallel preparation?

High solubility
High setting expansion
High film thickness
Low film thickness (Correct answer)

Correct answer: Low film thickness

Low film thickness is critical for long parallel-sided posts to allow full seating; excess thickness prevents the post from reaching full depth.

Question 96: Which of the following is an absolute contraindication to dental extractions without specialist consultation?

Controlled hypertension managed with amlodipine
Patient with a history of mild asthma using a salbutamol inhaler
Patient with well-controlled type 2 diabetes on metformin
Patient currently taking therapeutic doses of warfarin with INR of 3.8 (Correct answer)

Correct answer: Patient currently taking therapeutic doses of warfarin with INR of 3.8

An INR of 3.8 exceeds the safe threshold for dental extractions in primary care (generally INR should be ≤4.0 for simple extractions, but ideally ≤3.5 with local haemostatic measures). At this level, the bleeding risk is significantly elevated and specialist consultation is warranted to balance the risks of haemorrhage against thromboembolism from anticoagulant modification. The other conditions, when well controlled, are managed routinely in general practice.

Question 97: 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?

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

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

PMMA
UDMA
Bis-GMA (Correct answer)
TEGDMA

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 99: A patient requires a radiographic assessment of the TMJ (temporomandibular joint). Which imaging modality provides the best visualisation of the articular disc and soft tissue components?

MRI (magnetic resonance imaging) (Correct answer)
Lateral cephalometric radiograph
Dental panoramic tomograph (DPT)
Periapical radiograph

Correct answer: MRI (magnetic resonance imaging)

MRI is the gold standard for imaging the TMJ soft tissues, particularly the articular disc (meniscus). It provides excellent soft tissue contrast without ionising radiation, allowing assessment of disc position (normal, anterior displacement with or without reduction), disc morphology, joint effusion, and bone marrow changes. Sagittal and coronal sequences with open and closed mouth views demonstrate disc dynamics. CBCT/CT provides superior bone detail for osseous pathology (e.g., condylar erosion, osteophytes), while MRI is preferred for disc and soft tissue assessment.

Question 100: The process of 'stress relaxation' in impression materials refers to:

Water sorption during storage
Dimensional change on storage
Decrease in internal stress over time under constant strain (Correct answer)
Increased stiffness after setting

Correct answer: Decrease in internal stress over time under constant strain

Stress relaxation describes how a viscoelastic material that is held in a deformed state gradually reduces its internal stress without further change in strain.

Question 101: Hertwig's epithelial root sheath is derived from which structure?

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

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 102: The periodontal probe reading indicating moderate periodontitis is a pocket depth of:

>10 mm
4–6 mm (Correct answer)
1–3 mm
7–9 mm

Correct answer: 4–6 mm

Pocket depths of 4–6 mm typically indicate moderate periodontitis; readings >7 mm are associated with severe periodontitis according to the 2017 AAP/EFP classification.

Question 103: Which lymph nodes receive primary drainage from the tip of the tongue?

Submandibular nodes
Superior deep cervical nodes
Jugulodigastric 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 104: Which muscle forms the muscular floor ('diaphragm') of the oral cavity?

Geniohyoid
Anterior belly of digastric
Stylohyoid
Mylohyoid (Correct answer)

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 105: A 35-year-old patient presents with a sharp, lingering pain to cold stimuli in the lower left first molar (LL6). A deep distal carious lesion is visible on the bitewing radiograph, approaching the pulp. To confirm a diagnosis of irreversible pulpitis, which of the following sensibility tests is generally considered most reliable according to UK endodontic practice guidelines?

Electric Pulp Test (EPT)
Percussion test
Heat test using warm gutta-percha
Cold test using a refrigerant spray (e.g., Endo-Frost) (Correct answer)

Correct answer: Cold test using a refrigerant spray (e.g., Endo-Frost)

The British Endodontic Society and European Society of Endodontology guidelines recommend pulp sensibility testing to assess pulp status. Cold testing with a refrigerant spray is considered highly reliable and more accurate than EPT for routine diagnosis. It effectively elicits a response in cases of irreversible pulpitis, which is often sharp and lingering, helping to differentiate it from reversible pulpitis. The percussion test assesses periapical inflammation, not pulpal vitality, and heat tests are less commonly used as a primary diagnostic tool due to potential for causing pain and less predictable results.

Question 106: During surgical removal of an upper first premolar, the root fractures and the apical fragment is displaced into the maxillary sinus. What is the most appropriate initial management?

Instruct the patient to blow their nose forcefully to expel the fragment
Immediately enlarge the socket to retrieve the fragment via a Caldwell-Luc approach
Ignore the fragment as it will be absorbed naturally
Inform the patient, prescribe antibiotics and a nasal decongestant, and arrange a referral for surgical retrieval (Correct answer)

Correct answer: Inform the patient, prescribe antibiotics and a nasal decongestant, and arrange a referral for surgical retrieval

A root fragment displaced into the maxillary sinus should not be retrieved via the socket as this may enlarge the oroantral communication. The patient should be informed, prescribed antibiotics (amoxicillin) and a nasal decongestant (ephedrine nasal drops), given sinus precautions, and referred for elective surgical retrieval, usually via a Caldwell-Luc approach under general anaesthesia.

Question 107: 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)?

Take a radiograph to rule out a retained root and then suture the socket closed.
Vigorously curette the socket to stimulate bleeding and prescribe a course of amoxicillin.
Prescribe a strong opioid analgesic and advise hourly hot salt water mouthwashes.
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 108: 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 subepithelial blistering; pemphigoid shows intraepithelial blistering
Pemphigus vulgaris shows intraepithelial (suprabasal) blistering with acantholysis; mucous membrane pemphigoid shows subepithelial blistering with an intact basal layer (Correct answer)
Both conditions show identical histological features
Pemphigus vulgaris shows granulomatous inflammation; pemphigoid shows eosinophilic infiltrate

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 109: 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 is identical to medical CT in all respects
CBCT only shows soft tissues and cannot image bone or teeth
CBCT uses less radiation than a single periapical radiograph and has no limitations

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

Greater palatine foramen
Mandibular foramen (Correct answer)
Incisive foramen
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 111: A patient presents for extraction of a lower third molar. The radiograph shows the roots in close proximity to the inferior alveolar canal. Which sign on the radiograph is the MOST reliable indicator of a true intimate relationship between the tooth roots and the inferior alveolar nerve?

Loss of the lamina dura of the canal wall where the root crosses (Correct answer)
Darkening of the root at the point of overlap with the canal
Widening of the periodontal ligament space
The root appearing to curve away from the canal

Correct answer: Loss of the lamina dura of the canal wall where the root crosses

Loss (interruption) of the white corticated line of the inferior alveolar canal where the root crosses is the most reliable radiographic sign of a true intimate relationship. Other signs include darkening (increased radiolucency) of the root, deflection of the canal, and narrowing of the canal, but loss of the cortical outline is considered the strongest predictor of nerve injury risk.

Question 112: Prednisolone, a synthetic glucocorticoid, suppresses inflammation primarily by:

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

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 113: The 'Guidance Notes for Dental Practitioners on the Safe Use of X-ray Equipment' recommends a simplified two-tier system for rating the quality of radiographs. What are the two categories in this system?

Grade 1 / Grade 2
Excellent / Poor
Acceptable / Unacceptable
Diagnostically Acceptable / Not Diagnostically Acceptable (Correct answer)

Correct answer: Diagnostically Acceptable / Not Diagnostically Acceptable

The updated guidance from 2020 moved away from a previous three-tier system to a simpler two-tier system for image quality rating. Radiographs are now rated as either 'Diagnostically Acceptable' (A) or 'Not Diagnostically Acceptable' (N).

Question 114: A 45-year-old patient with no significant medical history develops sudden severe shortness of breath, widespread urticaria, and a rapid drop in blood pressure minutes after receiving a local anaesthetic. What is the most appropriate immediate pharmacological intervention according to Resuscitation Council UK guidelines?

Administer 500 micrograms of adrenaline (0.5 mL of 1:1000) via intramuscular injection. (Correct answer)
Administer 10mg of chlorphenamine via slow intravenous injection.
Administer 200mg of hydrocortisone via intramuscular injection.
Administer 2 puffs of a salbutamol inhaler.

Correct answer: Administer 500 micrograms of adrenaline (0.5 mL of 1:1000) via intramuscular injection.

The patient is exhibiting signs of anaphylaxis, a life-threatening emergency. The Resuscitation Council UK guidelines state that the immediate first-line treatment is an intramuscular injection of adrenaline (epinephrine). For an adult, the correct dose is 500 micrograms (0.5 mL of 1:1000 solution). While salbutamol, antihistamines (chlorphenamine), and corticosteroids (hydrocortisone) may be used as second-line treatments, adrenaline is the critical, life-saving initial intervention that must be administered without delay.

Question 115: Wickham's striae are a characteristic feature of which condition?

Pemphigus vulgaris
Oral lichen planus (Correct answer)
Erythema multiforme
Recurrent aphthous stomatitis

Correct answer: Oral lichen planus

Wickham's striae are fine white interlacing lines seen in reticular oral lichen planus and are considered pathognomonic of this condition.

Question 116: 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 117: Hyperthyroidism in a dental patient most relevantly affects dental management by:

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

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

pKa (Correct answer)
Protein binding
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 119: Which alloy system is most commonly used for high-strength dental casting alloys?

Cobalt-chromium (Correct answer)
Silver-tin
Nickel-titanium
Gold-palladium

Correct answer: Cobalt-chromium

Cobalt-chromium alloys are the most widely used base metal alloys for removable partial denture frameworks due to their high strength, hardness and corrosion resistance.

Question 120: 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?

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

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 121: 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?

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

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 122: Osteogenesis imperfecta is associated with which oral condition?

Taurodontism
Hypodontia
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 123: 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 VI (Correct answer)
Class IV
Class II
Class III

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 124: According to the IRMER (Ionising Radiation (Medical Exposure) Regulations 2017) in the UK, what are the three key roles defined in the regulations for dental radiography?

Dentist, nurse, and technician
Inspector, supervisor, and operator
Referrer (who requests the exposure), practitioner (who justifies the exposure), and operator (who carries out the practical aspects) (Correct answer)
Patient, radiographer, and consultant

Correct answer: Referrer (who requests the exposure), practitioner (who justifies the exposure), and operator (who carries out the practical aspects)

IRMER 2017 defines three key roles: the Referrer is the registered health professional who requests the radiograph with sufficient clinical information; the Practitioner (IR(ME)R practitioner) is entitled to justify the exposure by weighing the clinical benefit against the radiation risk; and the Operator carries out the practical aspects including positioning, exposure, processing, and quality assurance. In dental practice, the dentist may fulfil all three roles, though qualified dental nurses and dental therapists can act as operators.

Question 125: Which marker is elevated in Sjögren's syndrome and is used diagnostically?

ANCA
Anti-dsDNA
ANA only
Anti-Ro (SSA) and Anti-La (SSB) (Correct answer)

Correct answer: Anti-Ro (SSA) and Anti-La (SSB)

Anti-Ro (SSA) and Anti-La (SSB) antibodies are characteristic of Sjögren's syndrome and form part of the international diagnostic criteria for the condition.

Question 126: Which hepatitis virus is most commonly transmitted through needlestick injuries in dental practice, and what is the post-exposure prophylaxis protocol?

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 C — immediate interferon treatment
Hepatitis A — no prophylaxis needed
Hepatitis E — oral ribavirin prophylaxis

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).

Question 127: 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?

Auscultation of the carotid arteries for bruits (Correct answer)
Palpation of the cervical lymph nodes
Assessment of the temporomandibular joint (TMJ)
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 128: Carbamazepine is the drug of first choice for management of:

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

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 129: A 10-year-old patient is reviewed for a routine dental examination. The maxillary right deciduous canine is still present and firm, and the permanent canine is not palpable in the buccal sulcus. A parallax radiographic assessment confirms the permanent canine is palatally displaced. According to UK orthodontic guidelines, what is the most appropriate initial management?

Place a fixed appliance to create space for the canine.
Extract the deciduous canine and review eruption in 6-12 months. (Correct answer)
Monitor without intervention until the patient is 13 years old.
Immediately refer for surgical exposure and bonding of the ectopic canine.

Correct answer: Extract the deciduous canine and review eruption in 6-12 months.

For a palatally displaced maxillary canine in a 10-13 year old with sufficient arch space, the extraction of the deciduous canine is the recommended interceptive measure. This intervention has been shown to have a significant chance of encouraging the permanent canine to improve its position and erupt successfully without further intervention. Surgical exposure is considered only if this interceptive extraction fails.

Question 130: The oral manifestation of poorly controlled type 1 diabetes mellitus includes:

Increased caries resistance
Accelerated periodontitis and xerostomia (Correct answer)
Gingival hyperplasia
Hyposalivation alone

Correct answer: Accelerated periodontitis and xerostomia

Uncontrolled diabetes is associated with accelerated periodontal disease due to impaired neutrophil function, increased susceptibility to xerostomia and altered wound healing.

Question 131: Ranula is a mucocele arising from which gland?

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

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

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

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 133: 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 134: Which component of amalgam is primarily responsible for its corrosion resistance?

Silver
Copper (Correct answer)
Zinc
Tin

Correct answer: Copper

High-copper amalgam alloys suppress the corrosion-prone tin-mercury (gamma-2) phase by converting it to copper-tin (eta) phase, greatly improving corrosion resistance.

Question 135: Fluconazole is the drug of choice for treating which oral fungal infection?

Mucormycosis
Oropharyngeal candidiasis (Correct answer)
Cryptococcosis
Aspergillosis

Correct answer: Oropharyngeal candidiasis

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

Question 136: Leukaemia may present in the oral cavity with:

Enamel hypoplasia
Gingival hyperplasia due to leukaemic infiltration (Correct answer)
Bifid uvula
Tori mandibulares

Correct answer: Gingival hyperplasia due to leukaemic infiltration

Leukaemic infiltration of the gingival connective tissue, particularly in AML (M4/M5 monocytic subtypes), causes diffuse gingival enlargement with a characteristic reddish-purple appearance.

Question 137: The BEWE (Basic Erosive Wear Examination) score of 3 indicates:

Initial loss of surface texture
Hard tissue loss <50% of surface area
Hard tissue loss ≥50% of surface area (Correct answer)
No erosion

Correct answer: Hard tissue loss ≥50% of surface area

BEWE score 3 indicates severe erosive wear with hard tissue loss of 50% or more of the surface area, often exposing dentine extensively.

Question 138: 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)?

7.0 mg/kg (Correct answer)
4.4 mg/kg
2.2 mg/kg
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 139: A 52-year-old patient presents for a routine examination. Clinical assessment reveals probing depths up to 7mm and radiographic bone loss extending to the middle third of the root on the most severely affected teeth. Four teeth have been lost due to periodontitis. According to the 2017 Classification of Periodontal Diseases, as implemented by the British Society of Periodontology (BSP), what is the correct stage for this patient?

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

Correct answer: Stage IV

According to the 2017 classification system, Stage IV periodontitis is assigned when there is severe periodontal destruction (as seen in Stage III) plus additional complexities such as the loss of 5 or more teeth due to periodontitis, or the need for complex rehabilitation. While bone loss to the middle third and deep pockets are characteristic of Stage III, the loss of 4 teeth due to periodontitis is a complexity factor that, when combined with the severe destruction, can push the diagnosis to Stage IV, although the primary determinant for Stage IV is 5 or more teeth lost. However, given the options, Stage IV is the most appropriate classification due to the tooth loss and severity, distinguishing it from Stage III which is severe periodontitis without the need for complex rehabilitation or significant tooth loss (≤ 4 teeth lost).

Question 140: Which cells are responsible for forming dentine?

Osteoblasts
Ameloblasts
Cementoblasts
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 141: Which type of cementum covers the apical third of the root and contains cells?

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

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

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

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 143: According to the British National Formulary (BNF) and Resuscitation Council UK guidance, which of the following is an essential emergency drug that must be available in a UK dental practice for the management of a prolonged convulsive seizure (status epilepticus)?

Adrenaline 1:1000 injection
Glyceryl trinitrate (GTN) spray
Glucagon injection kit
Midazolam oromucosal solution (Correct answer)

Correct answer: Midazolam oromucosal solution

Midazolam oromucosal solution is the recommended drug for the management of prolonged or repeated convulsive seizures in a dental practice setting. Adrenaline is for anaphylaxis, GTN spray is for angina, and glucagon is for severe hypoglycaemia. While all are essential emergency drugs, Midazolam is specifically indicated for this type of epileptic emergency.

Question 144: Which class of antihypertensive drugs is most commonly associated with drug-induced gingival enlargement?

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

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 145: 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?

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

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

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

Correct answer: Type I

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

Question 147: 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 patient's age is over 70.
The duration of bisphosphonate use is greater than 5 years. (Correct answer)
The extraction is in the mandible.
The patient has a diagnosis of osteoporosis.

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 148: Ameloblastoma most commonly arises in which jaw location?

Anterior maxilla
Posterior mandible (Correct answer)
Anterior mandible
Posterior maxilla

Correct answer: Posterior mandible

Approximately 80% of ameloblastomas occur in the mandible, with the majority found in the posterior body and ramus region.

Question 149: 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?

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)
Allergic reaction to the local anaesthetic requiring antihistamine treatment
Fracture of the alveolar bone during extraction requiring surgical fixation

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 150: What is the initial emergency management of anaphylaxis in the dental surgery according to the UK Resuscitation Council guidelines?

Apply oxygen via nasal cannula and wait for the ambulance
Administer intravenous hydrocortisone only
Administer oral antihistamines and observe for 30 minutes
Administer intramuscular adrenaline 1:1000 (500 micrograms for an adult) into the anterolateral thigh, call 999, and position the patient supine with legs elevated (Correct answer)

Correct answer: Administer intramuscular adrenaline 1:1000 (500 micrograms for an adult) into the anterolateral thigh, call 999, and position the patient supine with legs elevated

The UK Resuscitation Council guidelines for anaphylaxis in the dental practice: 1) Call for help and dial 999; 2) Administer IM adrenaline 1:1000 (500 mcg/0.5 mL for adults) into the anterolateral thigh — repeat at 5-minute intervals if no improvement; 3) Position supine with legs elevated (sitting up if breathing difficulty); 4) High-flow oxygen 15 L/min; 5) IV access and fluids if trained; 6) Chlorphenamine 10 mg IM and hydrocortisone 200 mg IM as second-line treatments.

Question 151: Taste sensation from the anterior two-thirds of the tongue is conveyed by which nerve?

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

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

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

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

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

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

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

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 155: 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?

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

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

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

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 157: The recommended minimum ceramic thickness for an all-ceramic posterior crown to prevent fracture is approximately:

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

Correct answer: 1.5–2.0 mm

Current clinical guidelines recommend a minimum occlusal ceramic thickness of 1.5–2.0 mm for all-ceramic posterior crowns to provide sufficient fracture resistance under occlusal loading.

Question 158: Which oral condition is most characteristically associated with Crohn's disease?

Oral hairy leukoplakia
Orofacial granulomatosis with lip swelling, mucosal cobblestoning, and linear ulceration in the buccal sulcus (Correct answer)
Oral lichen planus
Geographic tongue

Correct answer: Orofacial granulomatosis with lip swelling, mucosal cobblestoning, and linear ulceration in the buccal sulcus

Orofacial granulomatosis (OFG) is the oral condition most characteristically associated with Crohn's disease. Features include labial swelling (particularly the lower lip), mucosal cobblestoning, linear ulceration in the buccal sulcus, mucosal tags, and angular cheilitis. Biopsy shows non-caseating granulomas identical to those found in intestinal Crohn's disease. OFG may precede intestinal symptoms by years.

Question 159: The maxillary teeth receive their primary arterial supply from branches of which artery?

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

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

Varicella
Hand foot and mouth disease
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 161: The acanthosis, elongation of rete ridges and parakeratosis seen on biopsy are most consistent with:

Chronic hyperplastic candidiasis
Oral lichen planus
Psoriasiform mucositis (Correct answer)
Leukoplakia with mild dysplasia

Correct answer: Psoriasiform mucositis

Psoriasiform mucositis shows elongated rete ridges, acanthosis and parakeratosis similar to psoriasis of the skin, and may be associated with geographic tongue or fissured tongue.

Question 162: What is the primary function of the stratum intermedium in the developing tooth?

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

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 163: Which bones form the floor of the orbit?

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

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

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

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 165: What is the bisecting angle technique for periapical radiography, and when might it be preferred over the paralleling technique?

It involves bisecting the tooth in half for measurement purposes
The X-ray beam is directed perpendicular to the bisector of the angle formed between the long axis of the tooth and the film/sensor plane; it may be preferred when palatal/floor of mouth anatomy prevents parallel placement of the sensor (Correct answer)
It is a technique used only for panoramic radiography
The film is placed at 45 degrees to the tooth and exposed from behind the patient

Correct answer: The X-ray beam is directed perpendicular to the bisector of the angle formed between the long axis of the tooth and the film/sensor plane; it may be preferred when palatal/floor of mouth anatomy prevents parallel placement of the sensor

In the bisecting angle technique, the film/sensor is placed as close to the tooth as possible (not necessarily parallel), and the X-ray beam is directed perpendicular to an imaginary line that bisects the angle between the long axis of the tooth and the plane of the sensor. This minimises image elongation or foreshortening. It may be preferred over the paralleling technique when anatomical limitations (shallow palate, torus, floor of mouth, small mouth) prevent parallel placement of the sensor behind the teeth. However, it is less geometrically accurate than the paralleling technique.

Question 166: A dental practice in the UK must register its use of X-ray equipment under IRR17. Which organisation is responsible for handling this registration?

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

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 167: 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)
High, Medium, Low Priority
Grade I, Grade II, Grade III Evidence
Urgent, Necessary, Elective

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

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 169: 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
Dicalcium phosphate
Tricalcium silicate

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 170: 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 causes direct necrosis of the periodontal ligament fibres.
It reduces the mineral content of alveolar bone, making it more susceptible to resorption.
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 171: 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?

Osteosarcoma
Peripheral giant cell granuloma (Correct answer)
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 172: Articaine differs from other amide local anaesthetics in that it contains:

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

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

Secretory IgA (Correct answer)
Lactoferrin
Amylase
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 174: The greater palatine nerve supplies the palatal mucosa in which region?

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

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

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

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 176: 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?

Paracetamol 500mg
Ibuprofen 400mg (Correct answer)
Dihydrocodeine 30mg
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 177: The nasopalatine nerve enters the hard palate through which foramen?

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

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 178: Which zone of the dental pulp is immediately deep to the odontoblast layer?

Subodontoblastic plexus
Central zone
Cell-free zone of Weil (Correct answer)
Cell-rich zone

Correct answer: Cell-free zone of Weil

The cell-free zone of Weil (also called the subodontoblastic zone) lies immediately beneath the odontoblast layer and is characterised by a relative absence of cell bodies.

Question 179: Bisphosphonates inhibit bone resorption primarily by targeting:

Fibroblasts
Osteoblasts
Osteocytes
Osteoclasts (Correct answer)

Correct answer: Osteoclasts

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

Question 180: 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
Anterior crossbite
Upper arch narrow with crowding

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.

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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