ORE Part 1 Dental Exam — Questions and Answers

Question 1: What local anaesthetic technique is used for maxillary anterior teeth?

Inferior dental block for maxillary incisors
Infiltration (supraperiosteal) injection buccally adjacent to the apex of each tooth — due to the thin buccal bone and cancellous structure of the maxilla allowing LA diffusion (Correct answer)
Intraligamentary injection only for all maxillary teeth
Posterior superior alveolar nerve block for all maxillary teeth

Correct answer: Infiltration (supraperiosteal) injection buccally adjacent to the apex of each tooth — due to the thin buccal bone and cancellous structure of the maxilla allowing LA diffusion

In the maxilla, infiltration anaesthesia (injecting above the root apex under the mucoperiosteum) is effective for most teeth due to the thin, porous buccal cortical bone allowing diffusion of the LA to reach the root and surrounding periodontium.

Question 2: What is the 'leeway space' in mixed dentition?

The space between erupting permanent teeth
The overjet and overbite combined
The size difference between primary canine and molars versus their permanent successors (premolars and canine) — typically 1.5 mm in maxilla and 2.5 mm in mandible (Correct answer)
The space created by caries in primary teeth

Correct answer: The size difference between primary canine and molars versus their permanent successors (premolars and canine) — typically 1.5 mm in maxilla and 2.5 mm in mandible

Leeway space is the additional space from the fact that primary canines and molars are wider mesiodistally than their permanent successors (canine + premolars). It is used to accommodate the permanent canines and correct minor crowding.

Question 3: Which hepatitis virus is most commonly transmitted through needlestick injuries in the dental setting?

Hepatitis B (Correct answer)
Hepatitis C
Hepatitis D
Hepatitis A

Correct answer: Hepatitis B

Hepatitis B has the highest transmission rate via needlestick injury (approximately 30% from an infected source), compared to hepatitis C (approximately 3%) and HIV (approximately 0.3%). This is why hepatitis B vaccination is mandatory for all dental healthcare workers in the UK.

Question 4: Addison's disease is characterised by insufficiency of which endocrine gland?

Parathyroid gland
Pituitary gland
Thyroid gland
Adrenal cortex (Correct answer)

Correct answer: Adrenal cortex

Addison's disease (primary adrenal insufficiency) results from destruction of the adrenal cortex, leading to deficiency of cortisol and aldosterone. Dental relevance includes risk of adrenal crisis during stress and characteristic oral hyperpigmentation. Steroid supplementation may be needed before invasive dental procedures.

Question 5: What is the most common complication following extraction of maxillary molars?

Ludwig's angina
Mandibular fracture
Inferior alveolar nerve damage
Oroantral communication (Correct answer)

Correct answer: Oroantral communication

Oroantral communication (OAC) is the most common complication of upper molar extractions due to the close relationship between the molar roots and the maxillary sinus floor. If the OAC is less than 2mm, it may close spontaneously; larger communications require surgical closure with a buccal advancement flap.

Question 6: What stabilises the tetragonal crystal phase of zirconia in yttria-stabilised tetragonal zirconia polycrystal (Y-TZP) ceramics?

Lithium disilicate glass matrix
Yttrium oxide (yttria) doping (Correct answer)
Rapid sintering at high temperature
Aluminium oxide additions

Correct answer: Yttrium oxide (yttria) doping

Yttrium oxide (yttria, Y2O3) is added in small amounts (3 mol%) to stabilise the tetragonal phase at room temperature, enabling transformation toughening when cracks propagate through the material.

Question 7: Which coagulation pathway is assessed by the prothrombin time (PT) and INR?

Intrinsic pathway
Fibrinolytic pathway
Extrinsic pathway (Correct answer)
Common pathway only

Correct answer: Extrinsic pathway

The PT/INR assesses the extrinsic and common coagulation pathways (factors VII, X, V, II, and fibrinogen). It is the standard monitoring test for warfarin therapy. The APTT, by contrast, assesses the intrinsic pathway and is used to monitor heparin therapy.

Question 8: What is the role of the 'referral criteria' in dental radiography?

Identifying which patients need dental implants
Determining the type of film to use
Evidence-based guidelines (e.g., FGDP Selection Criteria for Dental Radiography) that ensure X-rays are only taken when clinical benefit justifies the radiation risk — not as routine (Correct answer)
Selecting the exposure time for different patients

Correct answer: Evidence-based guidelines (e.g., FGDP Selection Criteria for Dental Radiography) that ensure X-rays are only taken when clinical benefit justifies the radiation risk — not as routine

Referral criteria (selection criteria) ensure radiographs are only prescribed when clinical information gained will positively influence patient management. Routine radiographs without clinical justification are unjustified exposures.

Question 9: What root configuration does the mandibular first molar typically have?

Three roots: two buccal and one lingual
One root with three canals
Two roots, each with a single canal
Two roots (mesial and distal), mesial root has two canals (Correct answer)

Correct answer: Two roots (mesial and distal), mesial root has two canals

The mandibular first molar typically has two roots: a mesial root (usually with two canals — mesiobuccal and mesiolingual) and a distal root (usually one or two canals).

Question 10: A patient presents with multiple oral ulcers, genital ulcers and ocular inflammation. Which condition should be suspected?

Pemphigus vulgaris
Behçet's disease (Correct answer)
Systemic lupus erythematosus
Crohn's disease

Correct answer: Behçet's disease

The triad of recurrent oral ulcers, genital ulcers and uveitis (ocular inflammation) is the classic presentation of Behçet's disease. It is a systemic vasculitis more common in populations along the ancient Silk Road and requires multidisciplinary management.

Question 11: Which drug interaction is relevant when prescribing metronidazole to a patient on warfarin?

No interaction — safe combination
Metronidazole inhibits CYP2C9 increasing warfarin levels and INR — bleeding risk increases significantly; warfarin dose reduction and INR monitoring required (Correct answer)
Only relevant if metronidazole is given for more than 10 days
Metronidazole reduces warfarin efficacy

Correct answer: Metronidazole inhibits CYP2C9 increasing warfarin levels and INR — bleeding risk increases significantly; warfarin dose reduction and INR monitoring required

Metronidazole significantly inhibits CYP2C9 (the enzyme primarily responsible for S-warfarin metabolism), raising warfarin plasma levels and INR substantially. This combination requires enhanced INR monitoring and likely warfarin dose reduction.

Question 12: What is the 'justification' principle in radiation protection and how does it apply to dental radiography?

All radiographs are automatically justified if taken by a dentist
Every radiation exposure must produce more benefit than detriment — exposures with no net benefit are unjustified and must not be taken (Correct answer)
Justification only applies to CT scanning
Routine radiographs on new patients are automatically justified regardless of clinical need

Correct answer: Every radiation exposure must produce more benefit than detriment — exposures with no net benefit are unjustified and must not be taken

Justification requires that every radiographic exposure must produce a net benefit (diagnostic information improving patient management) that outweighs the radiation risk. Exposures taken for administrative or routine purposes without clinical indication are unjustified.

Question 13: What radiographic changes are seen in chronic periodontitis on horizontal bitewing radiographs?

Apical radiolucency only
Horizontal or vertical alveolar bone loss with the bone crest more than 2 mm apical to the CEJ, loss of lamina dura and calculus deposits (Correct answer)
Increased bone density around affected teeth
No radiographic changes — diagnosis is clinical only

Correct answer: Horizontal or vertical alveolar bone loss with the bone crest more than 2 mm apical to the CEJ, loss of lamina dura and calculus deposits

Bitewing radiographs in periodontitis show: horizontal bone loss (bone crest >2 mm below CEJ), angular/vertical defects in severe cases, loss of lamina dura continuity, calculus deposits, and furcation radiolucencies in severe posterior cases.

Question 14: A patient with uncontrolled hyperthyroidism is at risk of which dental emergency?

Adrenal crisis
Thyroid crisis (thyroid storm) (Correct answer)
Hypoglycaemic episode
Myxoedema coma

Correct answer: Thyroid crisis (thyroid storm)

Thyroid crisis (thyroid storm) is a life-threatening exacerbation of hyperthyroidism that can be precipitated by stress, infection, or surgery. Signs include extreme tachycardia, hyperthermia, agitation, and cardiovascular collapse. Dental treatment should be deferred until the patient's thyroid function is controlled.

Question 15: A patient presents 3 days post-extraction with severe throbbing pain, a foul taste, and an empty socket with exposed bone. What is the diagnosis?

Alveolar osteitis (dry socket) (Correct answer)
Residual root fracture
Osteomyelitis
Normal post-extraction healing

Correct answer: Alveolar osteitis (dry socket)

Alveolar osteitis (dry socket) typically presents 2–5 days after extraction with severe pain, halitosis, and an empty socket where the blood clot has been lost or lysed. Risk factors include smoking, oral contraceptive use, and traumatic extraction. Management involves irrigation and placement of an obtundent dressing.

Question 16: A patient develops numbness of the lower lip immediately following extraction of a lower premolar. Which nerve has most likely been damaged?

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

Correct answer: Mental nerve

The mental nerve exits through the mental foramen, typically located between the apices of the lower premolars. During premolar extraction, the mental nerve can be damaged by direct trauma, excessive periosteal elevation, or compression, resulting in numbness of the lower lip and chin on the affected side.

Question 17: A 55-year-old patient on long-term bisphosphonate therapy for osteoporosis requires a dental extraction. What is the primary concern?

Drug interaction with local anaesthetic
Excessive bleeding
Medication-related osteonecrosis of the jaw (MRONJ) (Correct answer)
Increased risk of dry socket only

Correct answer: Medication-related osteonecrosis of the jaw (MRONJ)

MRONJ is a serious complication in patients taking bisphosphonates, particularly after invasive dental procedures. The SDCEP guidance recommends a thorough risk assessment, and extraction should only proceed when necessary, with appropriate consent regarding the risk of exposed necrotic bone that fails to heal.

Question 18: How many canals does a mandibular central incisor typically have?

No canal — solid dentine
3 canals in a bifurcated root
Commonly 2 canals (one labial, one lingual) in a single root — though may appear as one canal radiographically (Correct answer)
Always 1 canal

Correct answer: Commonly 2 canals (one labial, one lingual) in a single root — though may appear as one canal radiographically

The mandibular central incisor has a single root but often 2 canals (labial and lingual), which may join into one at the apex. This is important in endodontic treatment as the second canal is easily missed.

Question 19: A cone-cut error on a periapical radiograph appears as:

A clear unexposed area on part of the image (Correct answer)
Double exposure of teeth
A blurred image across the entire film
Excessive darkness of the entire image

Correct answer: A clear unexposed area on part of the image

A cone-cut occurs when the X-ray beam does not fully cover the receptor, resulting in a clear (unexposed) area on part of the image. It is caused by misalignment between the beam and the sensor/film and is more common with rectangular collimation. Film holders with beam-aiming devices help prevent this error.

Question 20: A patient collapses in the dental chair and is unresponsive with no pulse. What is the correct compression-to-ventilation ratio for adult CPR?

30:2 (Correct answer)
30:1
15:1
15:2

Correct answer: 30:2

The Resuscitation Council (UK) guidelines recommend a compression-to-ventilation ratio of 30:2 for adult basic life support. Compressions should be performed at a rate of 100–120 per minute, at a depth of 5–6 cm, with minimal interruptions. An AED should be applied as soon as available.

Question 21: What is the rationale for combining paracetamol and ibuprofen for post-operative dental pain?

They must be alternated, never taken together
They act via different mechanisms (central COX inhibition vs. peripheral prostaglandin reduction), providing additive/synergistic analgesia superior to either drug alone — multimodal approach (Correct answer)
Ibuprofen is always sufficient alone for all dental pain
Only one analgesic should be used at a time to avoid toxicity

Correct answer: They act via different mechanisms (central COX inhibition vs. peripheral prostaglandin reduction), providing additive/synergistic analgesia superior to either drug alone — multimodal approach

Paracetamol (central mechanism) and ibuprofen (peripheral/anti-inflammatory) target different components of the pain pathway, providing better combined analgesia than either alone, allowing lower doses of each while reducing side effects.

Question 22: What is the average root length of the maxillary central incisor?

8 mm
Approximately 13 mm (Correct answer)
5 mm
20 mm

Correct answer: Approximately 13 mm

The maxillary central incisor has a crown length of approximately 10–11 mm and a root length of approximately 13 mm, giving a total tooth length of approximately 23 mm on average.

Question 23: What is the mode of inheritance of dentinogenesis imperfecta?

X-linked recessive
Multifactorial with no single gene
Autosomal recessive
Autosomal dominant — caused by mutations in DSPP (dentin sialophosphoprotein) gene (Correct answer)

Correct answer: Autosomal dominant — caused by mutations in DSPP (dentin sialophosphoprotein) gene

Dentinogenesis imperfecta (DI types II and III) is inherited as autosomal dominant. It is caused by mutations in the DSPP gene. Affected teeth appear grey-blue/amber with bulbous crowns and obliterated pulp chambers.

Question 24: What is the 'broadest' tooth mesiodistally in the permanent dentition?

Maxillary canine
Mandibular first molar
Maxillary first molar (Correct answer)
Maxillary central incisor

Correct answer: Maxillary first molar

The maxillary first molar is the largest tooth by crown volume and one of the widest mesiodistally. It has the largest occlusal surface area of any posterior tooth, reflecting its dominant role in mastication.

Question 25: What is the definition of 'nociceptive pain' versus 'neuropathic pain'?

Neuropathic pain only affects the trigeminal nerve
Nociceptive: pain arising from tissue damage activating nociceptors (normal protective function); Neuropathic: pain arising from damage or dysfunction of the somatosensory nervous system itself (Correct answer)
Nociceptive pain is always acute; neuropathic pain is always chronic
They are synonymous — both describe tooth pain

Correct answer: Nociceptive: pain arising from tissue damage activating nociceptors (normal protective function); Neuropathic: pain arising from damage or dysfunction of the somatosensory nervous system itself

Nociceptive pain (e.g., from dental pulpitis, infection) results from activation of specialised pain receptors responding to tissue damage. Neuropathic pain (e.g., trigeminal neuralgia, PDAP) arises from abnormal processing in the pain pathway itself.

Question 26: What radiographic feature is characteristic of a dentigerous cyst?

Multilocular radiolucency with wispy septa
Opaque lesion with mixed density
Well-defined unilocular radiolucency with corticated borders enclosing the crown of an unerupted tooth from the CEJ (Correct answer)
Diffuse, ill-defined radiolucency at the apex of a vital tooth

Correct answer: Well-defined unilocular radiolucency with corticated borders enclosing the crown of an unerupted tooth from the CEJ

The dentigerous cyst appears on radiograph as a well-defined (corticated), unilocular radiolucency enclosing the crown of an unerupted (usually impacted) tooth, attached at the cemento-enamel junction.

Question 27: What is the rationale for prescribing dexamethasone before lower third molar surgery?

Prophylactic corticosteroid reduces post-operative trismus, swelling, and pain by suppressing inflammatory mediators before surgical trauma occurs (Correct answer)
To reduce anaesthetic requirements
To prevent dry socket
To treat infection preoperatively

Correct answer: Prophylactic corticosteroid reduces post-operative trismus, swelling, and pain by suppressing inflammatory mediators before surgical trauma occurs

Pre-operative dexamethasone (4–8 mg IM or IV) reduces post-surgical trismus, facial swelling, and pain by pre-emptively suppressing the inflammatory cascade. It is used in third molar surgery and other oral surgical procedures.

Question 28: What is the normal resting blood pressure range for a healthy adult according to NICE hypertension guidelines?

Below 150/90 mmHg
Below 130/85 mmHg
Below 140/90 mmHg (Correct answer)
Below 120/80 mmHg

Correct answer: Below 140/90 mmHg

NICE guidelines define hypertension as a clinic blood pressure persistently at or above 140/90 mmHg (with ambulatory or home monitoring confirmation at 135/85 mmHg). Below 140/90 is considered the normal range in clinical practice, though lower targets may apply for certain patient groups.

Question 29: Which fascial space infection carries the highest risk of airway compromise?

Buccal space
Ludwig's angina (bilateral submandibular space) (Correct answer)
Infraorbital space
Canine space

Correct answer: Ludwig's angina (bilateral submandibular space)

Ludwig's angina involves bilateral infection of the submandibular, sublingual, and submental spaces, causing rapid swelling of the floor of the mouth and tongue elevation. This can lead to fatal airway obstruction and is a surgical emergency requiring immediate hospital admission, IV antibiotics, and potentially surgical decompression or tracheostomy.

Question 30: During surgical extraction of a lower third molar, the lingual nerve is most at risk at which anatomical location?

At the lingual plate of the third molar region, just below the alveolar crest (Correct answer)
At the level of the sigmoid notch
At the lingula of the mandible
At the mental foramen

Correct answer: At the lingual plate of the third molar region, just below the alveolar crest

The lingual nerve runs in close proximity to the lingual plate in the third molar region, often lying at or just below the level of the alveolar crest. Studies have shown it is directly on the bone surface in approximately 15% of cases, making it vulnerable during flap elevation and bone removal.

Question 31: How many root canals does a mandibular first molar typically have?

Three (Correct answer)
Four
Five
Two

Correct answer: Three

The mandibular first molar typically has two roots (mesial and distal) with three root canals — two in the mesial root (mesiobuccal and mesiolingual) and one in the distal root. However, a second distal canal is found in approximately 30% of cases, making four canals common.

Question 32: What is a 'dentigerous cyst' and what does it arise from?

A traumatic cyst with no epithelial lining
A cyst arising from the rest of Malassez
A developmental odontogenic cyst forming around the crown of an unerupted tooth by accumulation of fluid between the crown and the reduced enamel epithelium (Correct answer)
An inflammatory cyst at the apex of a non-vital tooth

Correct answer: A developmental odontogenic cyst forming around the crown of an unerupted tooth by accumulation of fluid between the crown and the reduced enamel epithelium

The dentigerous cyst is the most common developmental odontogenic cyst. It develops from fluid accumulation between the crown and the reduced enamel epithelium of an unerupted (often impacted) tooth.

Question 33: What is 'submandibular space infection' (Ludwig's angina) and why is it a dental emergency?

A rapidly spreading bilateral cellulitis of the floor of mouth that can cause airway obstruction — often originating from a mandibular molar infection (Correct answer)
A mild gingival infection around the lower molars
A salivary gland stone
A viral infection of the floor of mouth

Correct answer: A rapidly spreading bilateral cellulitis of the floor of mouth that can cause airway obstruction — often originating from a mandibular molar infection

Ludwig's angina is a life-threatening bilateral submandibular/sublingual space infection, typically odontogenic (mandibular molars). Rapidly spreading inflammation raises the tongue, threatening the airway — emergency airway management may be required.

Question 34: What is the major inorganic component of dental enamel?

Calcium phosphate only
Collagen
Fluorapatite
Hydroxyapatite [Ca10(PO4)6(OH)2] — approximately 96% by weight (Correct answer)

Correct answer: Hydroxyapatite [Ca10(PO4)6(OH)2] — approximately 96% by weight

Dental enamel is approximately 96% inorganic by weight, primarily hydroxyapatite (calcium hydroxyapatite). The remaining 4% is water and organic matrix. This makes enamel the hardest biological substance in the human body.

Question 35: What is 'ghost teeth' (regional odontodysplasia)?

Teeth with taurodontism
Hypoplastic primary teeth following fluorosis
A rare developmental defect where teeth have very thin enamel and dentine with large pulp chambers, giving a ghost-like radiographic appearance (Correct answer)
A term for non-vital teeth with pulp necrosis

Correct answer: A rare developmental defect where teeth have very thin enamel and dentine with large pulp chambers, giving a ghost-like radiographic appearance

Regional odontodysplasia ('ghost teeth') is a rare developmental condition affecting multiple adjacent teeth. Severely defective enamel and dentine with enlarged pulp chambers give the pathognomonic 'ghost' radiographic appearance.

Question 36: What is the pharmacological basis for prescribing prophylactic amoxicillin before dental procedures?

Routine prophylaxis prevents bacteraemia
Current NICE guidance (NG178, 2008 updated) no longer recommends routine antibiotic prophylaxis for infective endocarditis in at-risk patients undergoing dental procedures in the UK (Correct answer)
Prophylaxis is mandatory for all implant procedures
All cardiac patients require amoxicillin before dentistry

Correct answer: Current NICE guidance (NG178, 2008 updated) no longer recommends routine antibiotic prophylaxis for infective endocarditis in at-risk patients undergoing dental procedures in the UK

NICE guideline NG178 (2008, updated 2016): antibiotic prophylaxis for infective endocarditis prevention is NOT recommended for any dental procedure in at-risk patients in the UK — in contrast to previous practice and some international guidelines.

Question 37: How should a pregnant dental worker's radiation exposure be managed?

Once pregnancy is declared, dose to the abdomen/foetus must not exceed 1 mSv for the remainder of pregnancy; reassign to limit exposure if workplace assessment indicates significant risk (Correct answer)
Pregnant workers must wear double lead aprons
No special precautions are needed during pregnancy for dental radiography
Pregnant workers must stop all radiography work immediately

Correct answer: Once pregnancy is declared, dose to the abdomen/foetus must not exceed 1 mSv for the remainder of pregnancy; reassign to limit exposure if workplace assessment indicates significant risk

IRR17 requires that once pregnancy is declared, the employer must ensure the dose to the foetus does not exceed 1 mSv for the remainder of pregnancy. Given typical dental X-ray scatter levels, this is rarely an issue, but a risk assessment must be carried out.

Question 38: What is 'centric occlusion' (maximum intercuspation, MIP)?

The mandibular position of maximum tooth contact regardless of condylar position (Correct answer)
The rest position of the mandible
The position of the mandible when the condyles are in centric relation
The position during chewing when vertical pressure is maximum

Correct answer: The mandibular position of maximum tooth contact regardless of condylar position

Centric occlusion (now termed Maximum Intercuspal Position — MIP) is the occlusal position where maximum tooth contact occurs. It may or may not coincide with centric relation (condyles in terminal hinge position).

Question 39: What is the 'Frankfort plane' and what is it used for in orthodontic assessment?

The palatal plane
A horizontal reference plane from the inferior margin of the orbit (orbitale) to the tragus/superior margin of the external auditory meatus — used as a standard reference in cephalometric analysis (Correct answer)
The occlusal plane
The mandibular plane

Correct answer: A horizontal reference plane from the inferior margin of the orbit (orbitale) to the tragus/superior margin of the external auditory meatus — used as a standard reference in cephalometric analysis

The Frankfort Horizontal plane is defined by the infraorbital rim and porion (external auditory meatus). It represents the natural head position and is a key reference plane in lateral cephalometric radiograph analysis.

Question 40: What is the correct dose of intramuscular adrenaline for an adult experiencing anaphylaxis in a dental surgery?

1ml of 1:10,000 (0.1mg)
0.5ml of 1:1000 (0.5mg) (Correct answer)
0.1ml of 1:1000 (0.1mg)
1ml of 1:1000 (1mg)

Correct answer: 0.5ml of 1:1000 (0.5mg)

The Resuscitation Council (UK) guidelines recommend 0.5ml of 1:1000 adrenaline (500 micrograms) given intramuscularly into the anterolateral thigh for adult anaphylaxis. This can be repeated every 5 minutes if there is no improvement. Intravenous adrenaline should only be given by experienced specialists.

Question 41: A diabetic patient becomes sweaty, confused, and tremulous during a dental appointment. What is the most appropriate immediate management?

Administer sublingual GTN
Give oral glucose gel or a sugary drink if conscious (Correct answer)
Place patient supine and wait
Administer intramuscular adrenaline

Correct answer: Give oral glucose gel or a sugary drink if conscious

These are signs of hypoglycaemia. If the patient is conscious and can swallow, the immediate treatment is oral glucose (glucose gel, tablets, or a sugary drink such as orange juice). If unconscious, intramuscular glucagon 1mg should be administered. This is a core medical emergency scenario for the GDC.

Question 42: Interglobular dentine is found primarily in which part of the tooth?

Within the pulp
In the crown dentine, just below the mantle dentine (Correct answer)
At the enamel surface
In the cementum

Correct answer: In the crown dentine, just below the mantle dentine

Interglobular dentine consists of areas of unmineralised or hypomineralised dentine found in the crown, just beneath the mantle dentine layer. It results from failure of the calcospherites (globular masses of mineralisation) to fuse completely during dentinogenesis.

Question 43: What is the role of tricyclic antidepressants (TCAs) in managing neuropathic orofacial pain?

TCAs are contraindicated in all orofacial pain management
TCAs only work for pain in depressed patients
TCAs (e.g., amitriptyline, nortriptyline) reduce central sensitisation and modulate descending pain inhibition — effective in low doses (10–75 mg) for neuropathic pain independently of antidepressant effect (Correct answer)
TCAs act by stimulating endogenous opioids only

Correct answer: TCAs (e.g., amitriptyline, nortriptyline) reduce central sensitisation and modulate descending pain inhibition — effective in low doses (10–75 mg) for neuropathic pain independently of antidepressant effect

Low-dose TCAs (amitriptyline 10–25 mg nightly) are first or second-line for neuropathic pain (PDAP, burning mouth, post-herpetic neuralgia). They modulate descending pain inhibitory pathways and reduce central sensitisation.

Question 44: What does ALARP mean in radiation protection?

As Low As Radiation Permits
Automatic Limit for All Radiation Protocols
As Low As Reasonably Practicable — exposures must be kept as low as reasonably achievable while still providing diagnostic benefit (Correct answer)
Always Limit All Radiation Procedures

Correct answer: As Low As Reasonably Practicable — exposures must be kept as low as reasonably achievable while still providing diagnostic benefit

ALARP (As Low As Reasonably Practicable) is the fundamental principle of radiation protection. Doses must be reduced to the lowest level that still provides adequate diagnostic information, weighing benefit against risk.

Question 45: What are the contraindications to prescribing ibuprofen for dental pain?

Mild renal impairment alone
Only relevant if the patient has diabetes
No contraindications exist for short-term dental use
Active peptic ulcer, severe renal impairment, third-trimester pregnancy, uncontrolled heart failure, hypersensitivity to NSAIDs/aspirin (Correct answer)

Correct answer: Active peptic ulcer, severe renal impairment, third-trimester pregnancy, uncontrolled heart failure, hypersensitivity to NSAIDs/aspirin

Ibuprofen is contraindicated in: active peptic ulceration, severe renal/hepatic impairment, third-trimester pregnancy (risk of premature ductus arteriosus closure), uncontrolled heart failure, and known NSAID hypersensitivity (including aspirin-exacerbated respiratory disease).

Question 46: Which cusp is the 'key cusp' for occlusal stability in the mandibular first molar?

Mesiolingual cusp (cusp of Carabelli equivalent — actually the dominant cusp of the lower first molar) (Correct answer)
The distolingual cusp
The distal cusp
The buccal cusps collectively

Correct answer: Mesiolingual cusp (cusp of Carabelli equivalent — actually the dominant cusp of the lower first molar)

The mesiolingual cusp of the mandibular first molar is the largest and most functionally significant cusp, occluding into the central fossa of the upper first molar. It is critical to occlusal stability.

Question 47: What is the recommended first-line analgesic regimen following dental extraction in an adult with no contraindications?

Aspirin 600mg four times daily
Diclofenac 50mg three times daily alone
Ibuprofen 400mg and paracetamol 1g taken together (Correct answer)
Codeine 60mg four times daily

Correct answer: Ibuprofen 400mg and paracetamol 1g taken together

The combination of ibuprofen 400mg and paracetamol 1g provides superior analgesia to either drug alone through synergistic action on different pain pathways. This combination is now recommended as first-line post-extraction analgesia in UK dental practice guidelines, avoiding the side effects of opioid-based alternatives.

Question 48: A patient with a known penicillin allergy (anaphylaxis) requires a dental antibiotic. Which antibiotic should be avoided?

All cephalosporins (due to cross-reactivity risk — approximately 1–2% with true anaphylaxis history, though generally amoxicillin is clearly contraindicated) (Correct answer)
Doxycycline — contraindicated in all allergies
Erythromycin — safe alternatives include clindamycin or metronidazole
Metronidazole only

Correct answer: All cephalosporins (due to cross-reactivity risk — approximately 1–2% with true anaphylaxis history, though generally amoxicillin is clearly contraindicated)

In a patient with confirmed anaphylactic penicillin allergy: amoxicillin (penicillin) and cephalosporins (cross-reactivity ~1–2%) should be avoided. Safe alternatives for dental infections include metronidazole, clarithromycin, or clindamycin.

Question 49: What is the mechanism of action of non-steroidal anti-inflammatory drugs (NSAIDs) in dentistry?

Reduce bacterial infection
Block opioid receptors
Inhibit cyclo-oxygenase (COX) enzymes, reducing prostaglandin synthesis, decreasing pain, inflammation, and fever (Correct answer)
Stimulate endogenous endorphin release

Correct answer: Inhibit cyclo-oxygenase (COX) enzymes, reducing prostaglandin synthesis, decreasing pain, inflammation, and fever

NSAIDs (ibuprofen, diclofenac) inhibit COX-1 and COX-2, reducing prostaglandin synthesis at sites of inflammation. This reduces sensitisation of peripheral nociceptors, providing analgesic and anti-inflammatory effects.

Question 50: A patient taking a selective serotonin reuptake inhibitor (SSRI) attends for dental treatment. Which drug interaction is most relevant in dentistry?

Reduced efficacy of local anaesthetic
Hypertensive crisis with adrenaline-containing LA
Increased risk of cardiac arrhythmia
Increased bleeding risk due to impaired platelet function (Correct answer)

Correct answer: Increased bleeding risk due to impaired platelet function

SSRIs inhibit serotonin reuptake into platelets, impairing platelet aggregation and increasing bleeding risk, particularly when combined with other antiplatelet agents or NSAIDs. Dentists should be aware of prolonged bleeding times and exercise caution during surgical procedures.

Question 51: Which type of hypersensitivity reaction is most commonly associated with local anaesthetic allergy in dentistry?

Type I (immediate/anaphylaxis)
Type II (cytotoxic)
Type IV (delayed/contact) (Correct answer)
Type III (immune complex)

Correct answer: Type IV (delayed/contact)

True allergy to local anaesthetics is extremely rare, but when it occurs with amide-type agents, it is most commonly a Type IV delayed hypersensitivity reaction (contact dermatitis). Type I anaphylactic reactions are more associated with ester-type local anaesthetics and preservatives.

Question 52: What is 'fog' on a dental radiograph and what causes it?

Only caused by patient movement
A sign of overexposure to X-rays only
A normal feature of all radiographs
Overall grey, low-contrast appearance caused by: light leakage in darkroom, expired film, improper processing, or secondary/scatter radiation reaching the film (Correct answer)

Correct answer: Overall grey, low-contrast appearance caused by: light leakage in darkroom, expired film, improper processing, or secondary/scatter radiation reaching the film

Radiographic fog is a general increase in film density reducing contrast and diagnostic quality. Causes include: secondary/scatter radiation, light leaks, outdated film, improper processing temperatures, or chemical contamination.

Question 53: The mesiolingual cusp of the maxillary first molar is sometimes called the 'cusp of':

Wilson
Nance (sometimes referred to as the dominant palatal cusp, related to Nance contact point) — though the Cusp of Carabelli is the additional cusp (Correct answer)
Spee
Carabelli — but this is the 5th accessory cusp; the mesiolingual is simply the largest cusp

Correct answer: Nance (sometimes referred to as the dominant palatal cusp, related to Nance contact point) — though the Cusp of Carabelli is the additional cusp

The mesiolingual cusp of the maxillary first molar is the largest cusp and is sometimes referred to in orthodontic literature as 'Nance's cusp'. The Cusp of Carabelli is a separate 5th accessory cusp on the mesiopalatal cusp.

Question 54: What is 'pericoronitis' and which tooth is most commonly affected?

Inflammation of the soft tissue operculum overlying an incompletely erupted tooth — most commonly the mandibular third molar (wisdom tooth) (Correct answer)
Inflammation around the apex of any tooth
Gingival inflammation around all erupting teeth
An abscess within the dental pulp

Correct answer: Inflammation of the soft tissue operculum overlying an incompletely erupted tooth — most commonly the mandibular third molar (wisdom tooth)

Pericoronitis is acute or chronic inflammation of the pericoronal flap (operculum) covering an incompletely erupted tooth. It is most commonly associated with the lower third molar, often complicated by bacterial colonisation under the flap.

Question 55: What is the pharmacological basis of conscious sedation using midazolam in dentistry?

Midazolam is an opioid agonist
Midazolam enhances GABA-A receptor activity, increasing chloride ion influx and reducing neuronal excitability — producing anxiolysis, sedation, amnesia, and muscle relaxation while maintaining consciousness (Correct answer)
Midazolam blocks sodium channels like local anaesthetics
Midazolam stimulates dopamine receptors

Correct answer: Midazolam enhances GABA-A receptor activity, increasing chloride ion influx and reducing neuronal excitability — producing anxiolysis, sedation, amnesia, and muscle relaxation while maintaining consciousness

Midazolam is a short-acting benzodiazepine that binds to GABA-A receptors, enhancing the inhibitory effect of GABA. This produces dose-dependent CNS depression: anxiolysis, sedation, anterograde amnesia, and muscle relaxation.

Question 56: A 45-year-old patient presents with a deep carious lesion on the mandibular first molar approaching the pulp. The tooth is vital with no spontaneous pain. What is the most appropriate treatment?

Immediate root canal treatment
Direct composite restoration without pulp protection
Extraction and implant placement
Indirect pulp capping with calcium hydroxide and restoration (Correct answer)

Correct answer: Indirect pulp capping with calcium hydroxide and restoration

Indirect pulp capping with calcium hydroxide is the treatment of choice for deep carious lesions in vital teeth without signs of irreversible pulpitis. This preserves pulp vitality by placing a biocompatible liner over the remaining thin dentine layer, promoting reparative dentine formation.

Question 57: What is 'allodynia' and when does it occur in dental/orofacial pain?

Normal pain from a stimulus that always causes pain
Pain radiating to distant sites
Pain only occurring at night
Pain from a stimulus that does not normally cause pain (e.g., light touch, air, cold water causing pain in irreversible pulpitis) — indicates sensitisation of the pain pathway (Correct answer)

Correct answer: Pain from a stimulus that does not normally cause pain (e.g., light touch, air, cold water causing pain in irreversible pulpitis) — indicates sensitisation of the pain pathway

Allodynia is pain elicited by normally non-painful stimuli (e.g., touch, temperature, air). It indicates sensitisation of the pain pathway (peripheral or central). In irreversible pulpitis, allodynia explains pain from non-noxious stimuli like cool water.

Question 58: What is the specific indication for using IV paracetamol (Perfalgan) in dental/oral surgical settings?

When oral route is unavailable or rapid onset analgesia is needed peri- or post-operatively under general anaesthesia — achieves therapeutic levels in 15 minutes (Correct answer)
Only for patients allergic to ibuprofen
For routine dental procedures in conscious patients
As a loading dose before oral paracetamol is started at home

Correct answer: When oral route is unavailable or rapid onset analgesia is needed peri- or post-operatively under general anaesthesia — achieves therapeutic levels in 15 minutes

IV paracetamol (Perfalgan) is used in hospital oral surgical settings when patients cannot take oral medication (post-GA) or rapid onset is needed. IV route achieves peak concentrations faster than oral, providing prompt perioperative analgesia.

Question 59: What is the role of the silane coupling agent in composite resin?

Forms a chemical bond between the organic resin matrix and inorganic filler particles (Correct answer)
Reduces volumetric polymerisation shrinkage
Prevents discolouration of the restoration over time
Initiates the polymerisation reaction when light-activated

Correct answer: Forms a chemical bond between the organic resin matrix and inorganic filler particles

Silane coupling agents create a chemical (covalent) bond between the organic resin matrix and the inorganic filler particle surface, which is critical for load transfer and durability.

Question 60: What is 'mutually protected occlusion'?

An occlusal scheme where posterior teeth protect anterior teeth in maximum intercuspation, and anterior teeth protect posterior teeth during excursive movements (Correct answer)
An occlusion where all teeth share equal occlusal loading
An occlusion requiring no restorative intervention
An occlusal scheme used only for complete dentures

Correct answer: An occlusal scheme where posterior teeth protect anterior teeth in maximum intercuspation, and anterior teeth protect posterior teeth during excursive movements

In mutually protected (organically) occlusion: the posterior teeth protect anterior teeth from heavy vertical loading in MIP; the anterior teeth (canine guidance or group function) disocclude the posterior teeth during excursive movements.

Question 61: Which permanent tooth has the longest root?

Maxillary central incisor
Mandibular first molar
Mandibular central incisor
Maxillary canine (Correct answer)

Correct answer: Maxillary canine

The maxillary canine has the longest root of all permanent teeth, making it very stable in the arch and explaining why it is typically the last anterior tooth extracted when arch preservation is needed.

Question 62: What is the pathogenesis of ANUG (acute necrotising ulcerative gingivitis)?

A viral gingivitis
A single bacterial species infection
Polymicrobial infection dominated by spirochaetes and fusiform bacteria (Treponema, Fusobacterium) causing necrosis of interdental papillae in immunocompromised or stressed patients (Correct answer)
An allergic reaction to oral bacteria

Correct answer: Polymicrobial infection dominated by spirochaetes and fusiform bacteria (Treponema, Fusobacterium) causing necrosis of interdental papillae in immunocompromised or stressed patients

ANUG is characterised by painful necrosis of interdental papillae with punched-out crater formation. It is caused by synergistic anaerobic bacterial infection (spirochaetes, Fusobacterium, Prevotella) in predisposed individuals (stress, smoking, malnutrition, HIV).

Question 63: What is 'scalloped' basement membrane in the gingival epithelium?

The attachment of junctional epithelium to enamel
The scalloped gingival margin shape
The CEJ morphology
The undulating interface between the epithelium and underlying connective tissue, formed by rete ridges and connective tissue papillae (Correct answer)

Correct answer: The undulating interface between the epithelium and underlying connective tissue, formed by rete ridges and connective tissue papillae

The gingival epithelium has a scalloped (rete ridge) interface with the lamina propria. Rete ridges interdigitate with connective tissue papillae, increasing surface area and enhancing mechanical attachment.

Question 64: Which of the following is an absolute contraindication to dental extraction without specialist referral?

History of mild penicillin allergy
Patients receiving intravenous bisphosphonate therapy for bone metastases (Correct answer)
Patients on low-dose aspirin
Well-controlled type 2 diabetes

Correct answer: Patients receiving intravenous bisphosphonate therapy for bone metastases

Patients on intravenous bisphosphonates (e.g., zoledronic acid for bone metastases) have a significantly elevated risk of MRONJ compared to oral bisphosphonate users. These patients should be referred to a specialist oral surgery unit for extraction with appropriate planning and follow-up.

Question 65: What opioid is commonly prescribed for moderate-to-severe dental pain?

Morphine sulphate as first-line
Codeine phosphate (30–60 mg) combined with paracetamol, or dihydrocodeine as alternatives in UK primary dental care (Correct answer)
Fentanyl patches
Heroin (diamorphine) in hospital only

Correct answer: Codeine phosphate (30–60 mg) combined with paracetamol, or dihydrocodeine as alternatives in UK primary dental care

In UK primary dental care, codeine phosphate (mild opioid) combined with paracetamol is used for moderate dental pain. Stronger opioids are reserved for hospital settings or specific circumstances under specialist care.

Question 66: Which type of composite resin contains the smallest filler particle size?

Hybrid composite (0.4–5 μm)
Microfilled composite (0.04–0.4 μm) (Correct answer)
Packable composite (0.7–3.5 μm)
Macrofilled composite (10–50 μm)

Correct answer: Microfilled composite (0.04–0.4 μm)

Microfilled composites contain colloidal silica particles of 0.04–0.4 μm, giving them outstanding polish retention and smooth surface finish, though at the cost of lower mechanical strength.

Question 67: What concentration of articaine is most commonly used for dental local anaesthesia?

10% lignocaine topical only
2% lignocaine alone
4% articaine with 1:100,000 adrenaline (Correct answer)
0.5% bupivacaine

Correct answer: 4% articaine with 1:100,000 adrenaline

4% articaine with 1:100,000 adrenaline (epinephrine) is the most commonly used dental local anaesthetic in the UK for routine procedures. The vasoconstrictor prolongs duration and reduces systemic absorption.

Question 68: What is the pathogenesis of periapical abscess formation?

Viral infection of the periapical tissues
An allergic reaction to pulp bacteria
Bacterial products from pulp necrosis spread beyond the apex, triggering acute inflammation with neutrophil accumulation and pus formation in the periapical tissues (Correct answer)
Direct bacterial spread from the gingival pocket

Correct answer: Bacterial products from pulp necrosis spread beyond the apex, triggering acute inflammation with neutrophil accumulation and pus formation in the periapical tissues

Pulp necrosis from caries/trauma allows bacteria to colonise the root canal. Bacteria and their products exit the apex, stimulating acute inflammatory infiltrate (mainly neutrophils), resulting in pus accumulation (abscess) in periapical bone or soft tissue.

Question 69: What is the clinical significance of 'Ramsay Hunt syndrome' in dental practice?

A TMJ condition causing pain
A salivary gland condition causing xerostomia
Trigeminal neuralgia secondary to herpes
Varicella-zoster virus reactivation in the geniculate ganglion causing unilateral facial palsy, ear pain, and vesicles in the ear canal and soft palate — requiring antiviral treatment and dental/neurological awareness (Correct answer)

Correct answer: Varicella-zoster virus reactivation in the geniculate ganglion causing unilateral facial palsy, ear pain, and vesicles in the ear canal and soft palate — requiring antiviral treatment and dental/neurological awareness

Ramsay Hunt syndrome (herpes zoster oticus) involves VZV reactivation in CN VII (geniculate ganglion), causing lower motor neuron facial palsy, severe ear pain (otalgia), and vesicles in the EAC and soft palate. Urgent antiviral therapy is needed.

Question 70: Which cells are responsible for dentine formation?

Cementoblasts
Ameloblasts
Osteoblasts
Odontoblasts (Correct answer)

Correct answer: Odontoblasts

Odontoblasts are the dentine-forming cells derived from neural crest cells. They line the pulp chamber and extend processes into dentinal tubules (Tomes' fibres), producing predentine which mineralises to become dentine.

Question 71: What is the dose-area product (DAP) and why is it recorded?

DAP measures the total radiation energy delivered (dose × area of beam) in mGy·cm² — recorded for quality assurance, dose optimisation, and IR(ME)R audit requirements (Correct answer)
DAP recording is optional and not required in dental practice
DAP is the same as the effective dose in sieverts
DAP is only measured for panoramic radiographs

Correct answer: DAP measures the total radiation energy delivered (dose × area of beam) in mGy·cm² — recorded for quality assurance, dose optimisation, and IR(ME)R audit requirements

DAP (dose-area product) represents the absorbed dose multiplied by the area of the beam at the point of measurement, giving total radiation output. Recording DAP is required under IR(ME)R 2017 for audit and dose optimisation purposes.

Question 72: Which monomer is the primary liquid component in heat-cured PMMA denture base resins?

Ethyl methacrylate (EMA)
Urethane dimethacrylate (UDMA)
Methyl methacrylate (MMA) (Correct answer)
Bisphenol A-glycidyl methacrylate (Bis-GMA)

Correct answer: Methyl methacrylate (MMA)

Methyl methacrylate (MMA) is the primary liquid monomer in conventional PMMA denture base resins; when polymerised it forms polymethyl methacrylate (PMMA).

Question 73: The dental papilla gives rise to which structure of the developed tooth?

Cementum
Dentine and pulp (Correct answer)
Periodontal ligament
Enamel

Correct answer: Dentine and pulp

The dental papilla is the ectomesenchymal condensation that forms the core of the developing tooth germ. It differentiates into odontoblasts (which form dentine) and the dental pulp. The dental follicle, in contrast, gives rise to cementum, periodontal ligament, and alveolar bone.

Question 74: What is the angle formed between the occlusal plane and the condylar guidance path called?

The Bennett angle
The Monson angle
The Frankfort angle
The Fischer angle (or Bennett angle — actually these differ; the angle between condylar path and occlusal plane is the Balkwill angle) (Correct answer)

Correct answer: The Fischer angle (or Bennett angle — actually these differ; the angle between condylar path and occlusal plane is the Balkwill angle)

The Balkwill angle (approximately 26°) is formed between the occlusal plane and the path of the condyle. The Bennett angle is the angle formed by the working side condyle moving laterally.

Question 75: What is the purpose of the 'FGDP Selection Criteria for Dental Radiography'?

A set of national standards for digital sensor calibration
A legal requirement superseding IR(ME)R
A guide to radiographic processing techniques
Evidence-based guidance for UK dentists on when radiographs are clinically justified — specific criteria for new patients, recall intervals, and specific clinical situations (Correct answer)

Correct answer: Evidence-based guidance for UK dentists on when radiographs are clinically justified — specific criteria for new patients, recall intervals, and specific clinical situations

The FGDP (Faculty of General Dental Practice, UK) Selection Criteria provide evidence-based guidance on clinical situations justifying radiographic exposures, including recall bitewing intervals, periapical indications, and specific clinical scenarios.

Question 76: Which type of white blood cell is most increased in a bacterial infection?

Neutrophils (Correct answer)
Eosinophils
Basophils
Lymphocytes

Correct answer: Neutrophils

Neutrophils are the primary phagocytic cells of the innate immune system and are the first responders to bacterial infection. A raised neutrophil count (neutrophilia) on a full blood count is a hallmark of acute bacterial infection. Lymphocytosis, in contrast, is more associated with viral infections.

Question 77: What is the dental significance of long-term steroid therapy?

Adrenal suppression may cause an 'adrenal crisis' under surgical stress — doubling of steroid dose ('steroid cover') or consultation with medical team required before invasive procedures (Correct answer)
No dental significance
Only relevant if steroids are given intravenously
Steroids only affect healing, not emergency risk

Correct answer: Adrenal suppression may cause an 'adrenal crisis' under surgical stress — doubling of steroid dose ('steroid cover') or consultation with medical team required before invasive procedures

Long-term systemic steroids suppress the HPA axis (adrenal suppression). Surgical stress cannot trigger the normal cortisol surge, risking Addisonian crisis (hypotension, collapse). Historically, 'steroid cover' was applied; current guidance is more nuanced and patient-specific.

Question 78: What is 'hyperalgesia' in the context of acute pulpitis?

A type of referred pain
Normal pain response to dental caries
Reduced pain sensitivity caused by inflammation
Increased sensitivity to painful stimuli — in pulpitis, inflammation sensitises C fibres lowering their threshold, causing disproportionate pain responses to normally painful stimuli (Correct answer)

Correct answer: Increased sensitivity to painful stimuli — in pulpitis, inflammation sensitises C fibres lowering their threshold, causing disproportionate pain responses to normally painful stimuli

Hyperalgesia is an exaggerated pain response to a normally painful stimulus. In irreversible pulpitis, inflammatory mediators (bradykinin, prostaglandins) sensitise C fibres, lowering their threshold and causing heightened pain responses.

Question 79: Which investigation is most appropriate for assessing the relationship between an impacted lower third molar and the inferior alveolar canal?

Periapical radiograph
Upper standard occlusal radiograph
Lateral cephalogram
Cone beam computed tomography (CBCT) (Correct answer)

Correct answer: Cone beam computed tomography (CBCT)

CBCT provides three-dimensional imaging that accurately demonstrates the spatial relationship between the impacted tooth roots and the inferior alveolar canal. NICE guidelines recommend CBCT when conventional radiographs show signs of a close relationship, such as darkening of roots or interruption of the canal outline.

Question 80: What is the approximate working time of zinc phosphate cement when mixed at room temperature (23°C)?

1–2 minutes
7–9 minutes
10–12 minutes
3–5 minutes (Correct answer)

Correct answer: 3–5 minutes

Zinc phosphate cement has a working time of approximately 3–5 minutes at 23°C, which can be extended by cooling the mixing slab to slow the exothermic reaction.

Question 81: What does IL-1β (interleukin-1 beta) do in periodontal disease?

Promotes gingival healing and collagen synthesis
A pro-inflammatory cytokine produced by macrophages that stimulates bone resorption (via RANKL pathway) and collagenase production — a key mediator of periodontal tissue destruction (Correct answer)
Inhibits bone resorption
Has no role in periodontal bone loss

Correct answer: A pro-inflammatory cytokine produced by macrophages that stimulates bone resorption (via RANKL pathway) and collagenase production — a key mediator of periodontal tissue destruction

IL-1β is a pivotal pro-inflammatory cytokine in periodontitis. It stimulates osteoclast activity through RANKL upregulation causing bone loss, promotes collagenase (MMP) production destroying collagen, and perpetuates the inflammatory cycle.

Question 82: What is the pharmacological basis of topical benzydamine hydrochloride (Difflam) for oral mucosal pain?

A corticosteroid applied topically
An antibiotic mouthwash
A topical antifungal agent
An NSAID with local anaesthetic properties applied topically to oral mucosa — inhibits prostaglandin synthesis and has analgesic effect on inflamed mucosal surfaces (Correct answer)

Correct answer: An NSAID with local anaesthetic properties applied topically to oral mucosa — inhibits prostaglandin synthesis and has analgesic effect on inflamed mucosal surfaces

Benzydamine (Difflam) is a topical NSAID/local analgesic mouthwash effective for painful oral mucositis (from radiotherapy, chemotherapy, or surgery) and aphthous ulcers. It inhibits prostaglandin synthesis and provides surface anaesthesia.

Question 83: Which structure appears as a radiolucent band across the roots of maxillary teeth on a DPT (OPG)?

Air shadow of the oropharynx (Correct answer)
Nasal septum
Maxillary sinus floor
Hard palate shadow

Correct answer: Air shadow of the oropharynx

The oropharyngeal airway creates a characteristic radiolucent (dark) band that is superimposed across the roots of the anterior teeth on a DPT. This is a normal anatomical shadow and should not be confused with pathology. Asking the patient to place their tongue against the palate during exposure helps reduce this artefact.

Question 84: A 12-year-old child falls and avulses a permanent upper central incisor. The tooth has been dry for 45 minutes. What is the recommended reimplantation protocol?

Soak in Hank's balanced salt solution for 30 minutes then reimplant
Reimplant immediately without any preparation
Soak in sodium fluoride solution, remove necrotic PDL, then reimplant and accept need for later root canal treatment (Correct answer)
Do not reimplant as the prognosis is poor

Correct answer: Soak in sodium fluoride solution, remove necrotic PDL, then reimplant and accept need for later root canal treatment

When extra-alveolar dry time exceeds 60 minutes (or the PDL is clearly non-viable), the International Association of Dental Traumatology guidelines recommend removing the necrotic PDL, treating the root surface with fluoride, and reimplanting. Root canal treatment will be needed as revascularisation will not occur, but reimplantation preserves alveolar bone for later definitive treatment.

Question 85: Why can inferior dental block (IDB) fail in acute pulpitis?

IDB never fails — technique error only explains failure
Inflammation lowers local tissue pH, converting the LA from lipid-soluble base form (which crosses membranes) to ionised form — reducing LA efficacy; also peripheral sensitisation lowers nociceptor thresholds (Correct answer)
LA is degraded by inflammatory enzymes
The mandibular canal is inaccessible in infection

Correct answer: Inflammation lowers local tissue pH, converting the LA from lipid-soluble base form (which crosses membranes) to ionised form — reducing LA efficacy; also peripheral sensitisation lowers nociceptor thresholds

Inflamed tissue has a lower pH. LA (pKa ~7.8) requires unionised base form to cross nerve membranes. In acidic inflamed tissue, more LA is in the ionised form, reducing membrane penetration and block efficacy. Also, sensitised C fibres fire at lower thresholds.

Question 86: Which cranial nerve is responsible for the motor supply to the muscles of mastication?

Hypoglossal nerve (XII)
Glossopharyngeal nerve (IX)
Facial nerve (VII)
Trigeminal nerve (V) — mandibular division (Correct answer)

Correct answer: Trigeminal nerve (V) — mandibular division

The mandibular division (V3) of the trigeminal nerve provides motor innervation to the muscles of mastication (masseter, temporalis, medial and lateral pterygoids) as well as mylohyoid, anterior belly of digastric, tensor veli palatini, and tensor tympani.

Question 87: A patient with a known cardiac murmur is scheduled for dental extraction. According to current NICE guidelines, what is the recommended antibiotic prophylaxis regimen?

No routine antibiotic prophylaxis is recommended (Correct answer)
Azithromycin 500mg orally one hour before
Amoxicillin 3g orally one hour before
Clindamycin 600mg orally one hour before

Correct answer: No routine antibiotic prophylaxis is recommended

NICE Clinical Guideline CG64 (updated) states that antibiotic prophylaxis against infective endocarditis is NOT routinely recommended for dental procedures in the UK, regardless of the cardiac condition. This differs from American Heart Association guidelines and is a key point for the ORE examination.

Question 88: A patient on warfarin with an INR of 3.2 presents for extraction of a single-rooted tooth. According to SDCEP guidance, what is the recommended approach?

Convert to heparin bridging therapy
Stop warfarin 3 days before extraction
Proceed with extraction using local haemostatic measures (Correct answer)
Postpone until INR is below 2.0

Correct answer: Proceed with extraction using local haemostatic measures

SDCEP guidance recommends that patients with a stable INR of 4.0 or below can have up to 3 simple extractions in general practice with local haemostatic measures (oxidised cellulose, sutures, tranexamic acid mouthwash). Warfarin should NOT be stopped as the thromboembolic risk outweighs the bleeding risk.

Question 89: Which nerve provides sensory innervation to the buccal gingivae of the mandibular molars?

Mylohyoid nerve
Inferior alveolar nerve
Mental nerve
Long buccal nerve (Correct answer)

Correct answer: Long buccal nerve

The long buccal nerve (buccal branch of the mandibular division of the trigeminal nerve) provides sensory innervation to the buccal gingivae of the mandibular molars. This is why a separate long buccal nerve block is required in addition to an inferior alveolar nerve block when extracting lower molars.

Question 90: What are A-delta and C fibres in the context of dental pain?

A-delta fibres: myelinated, fast-conducting (sharp, well-localised pain); C fibres: unmyelinated, slow-conducting (dull, burning, poorly localised, thermal pain) — both transmit nociceptive signals in dental pulp (Correct answer)
A-delta fibres carry light touch only
A-delta and C are both types of motor nerve fibres
C fibres only carry proprioception from the PDL

Correct answer: A-delta fibres: myelinated, fast-conducting (sharp, well-localised pain); C fibres: unmyelinated, slow-conducting (dull, burning, poorly localised, thermal pain) — both transmit nociceptive signals in dental pulp

Both nerve types carry nociceptive signals from dental pulp and periodontium. A-delta fibres produce the sharp, well-localised 'first pain' response. C fibres produce the dull, burning, poorly localised 'second pain' response.

Question 91: What is the aetiology of dental caries according to the Keyes Circle?

Genetic susceptibility alone
Fluoride deficiency alone
Single bacterial infection without diet involvement
Interaction of three factors: susceptible host (tooth), cariogenic microorganisms (Streptococcus mutans, Lactobacilli), and fermentable substrate (sugars) — all three must be present (Correct answer)

Correct answer: Interaction of three factors: susceptible host (tooth), cariogenic microorganisms (Streptococcus mutans, Lactobacilli), and fermentable substrate (sugars) — all three must be present

The Keyes model (later expanded to include time) describes caries as arising from the interaction of susceptible tooth surfaces, cariogenic bacteria, and dietary fermentable carbohydrates over time.

Question 92: According to the BNF, what is the first-line analgesic for post-extraction dental pain?

Tramadol
Opioid patch
Codeine phosphate alone
Ibuprofen 400 mg three times daily (if not contraindicated) or paracetamol 1g four times daily (Correct answer)

Correct answer: Ibuprofen 400 mg three times daily (if not contraindicated) or paracetamol 1g four times daily

For post-extraction pain, ibuprofen 400 mg TDS is first-line if no contraindications. Paracetamol 1g QDS is used if NSAIDs are contraindicated. Combination (ibuprofen + paracetamol) provides superior analgesia to either alone.

Question 93: Which of the following is the most appropriate initial management for a patient presenting with acute necrotising ulcerative gingivitis (ANUG)?

Metronidazole 400mg three times daily for 3 days and gentle debridement (Correct answer)
Chlorhexidine mouthwash alone
Scaling and root planing under local anaesthetic
Referral for biopsy

Correct answer: Metronidazole 400mg three times daily for 3 days and gentle debridement

ANUG is managed initially with metronidazole (the antimicrobial of choice targeting the anaerobic fusiform and spirochaete bacteria), gentle superficial debridement, and oral hygiene instruction. Aggressive scaling should be avoided in the acute phase due to pain and risk of bacteraemia.

Question 94: What oral manifestation is characteristic of Addison's disease?

Diffuse melanotic (brown) pigmentation of the oral mucosa, particularly the buccal mucosa (Correct answer)
Petechiae on the palate
White patches on the tongue
Painful ulcers on the lip

Correct answer: Diffuse melanotic (brown) pigmentation of the oral mucosa, particularly the buccal mucosa

Addison's disease (primary adrenal insufficiency) causes excess ACTH secretion which stimulates melanocytes, producing diffuse mucosal hyperpigmentation, characteristically on the buccal mucosa, gingivae, and lips.

Question 95: What is the 'working side' in lateral excursion of the mandible?

The side towards which the mandible moves during lateral jaw movement (Correct answer)
The non-chewing side
The side where the condyle makes a Bennett movement
The side where the condyle moves straight

Correct answer: The side towards which the mandible moves during lateral jaw movement

The working side (chewing side) is the side towards which the mandible moves in lateral excursion. The working-side condyle pivots and rotates; the balancing-side condyle makes a translatory Bennett movement.

Question 96: What is the pharmacological management of post-herpetic neuralgia (PHN) affecting the trigeminal nerve?

Penicillin antibiotic therapy
Amitriptyline (TCA), gabapentin/pregabalin (calcium channel modulators), lidocaine patches, or capsaicin cream — NICE-recommended neuropathic pain treatments (Correct answer)
NSAIDs as first-line
Surgical decompression as first-line

Correct answer: Amitriptyline (TCA), gabapentin/pregabalin (calcium channel modulators), lidocaine patches, or capsaicin cream — NICE-recommended neuropathic pain treatments

PHN (persisting pain after herpes zoster/shingles) affecting the trigeminal distribution is managed with NICE-recommended neuropathic pain agents: amitriptyline, gabapentin or pregabalin, topical lidocaine, or capsaicin 8% patch.

Question 97: What is the 'inverted Y' radiopaque shadow on a dental panoramic tomograph?

The intersection of the nasal septum and lateral border of the nose creating an inverted Y shape over the upper incisor region on DPT — a normal anatomical landmark (Correct answer)
The mandibular canal bifurcation
A sign of unerupted upper incisor
A sign of pathology requiring investigation

Correct answer: The intersection of the nasal septum and lateral border of the nose creating an inverted Y shape over the upper incisor region on DPT — a normal anatomical landmark

On a DPT, the nasal septum and the floor/lateral wall of the nasal cavity form an inverted Y-shaped radiopaque shadow projected over the upper incisor region — a normal radiographic anatomical feature.

Question 98: What anatomical structure separates the anterior and posterior cranial fossae?

The cribriform plate of the ethmoid
The lesser wing of the sphenoid and the petrous part of the temporal bone (forming the floor boundaries) (Correct answer)
The frontal ridge
The occipital bone

Correct answer: The lesser wing of the sphenoid and the petrous part of the temporal bone (forming the floor boundaries)

The boundary between the anterior and middle cranial fossae is formed by the lesser wing of the sphenoid and the anterior clinoid processes. This is relevant in dental anatomy when understanding skull base relationships.

Question 99: Chlorhexidine gluconate mouthwash should not be used immediately after which toothpaste ingredient?

Triclosan
Sodium lauryl sulphate (SLS) (Correct answer)
Fluoride
Calcium carbonate

Correct answer: Sodium lauryl sulphate (SLS)

Sodium lauryl sulphate (SLS), the foaming agent in most toothpastes, is an anionic surfactant that interacts with the cationic chlorhexidine molecule, inactivating it. Patients should wait at least 30 minutes after brushing before using chlorhexidine mouthwash, or use an SLS-free toothpaste.

Question 100: During elevation of a lower third molar root, the root tip is displaced lingually. What is the immediate best course of action?

Attempt retrieval with a Mitchell's trimmer through the socket
Take a radiograph, note the location, and refer to a specialist oral surgeon (Correct answer)
Raise a lingual flap and retrieve under direct vision
Leave it and inform the patient

Correct answer: Take a radiograph, note the location, and refer to a specialist oral surgeon

A displaced root fragment in the lingual tissues should not be pursued through the socket or by raising a lingual flap in a general practice setting, as this risks lingual nerve damage and displacement into deeper tissue spaces. The correct approach is to document the event radiographically and refer to a specialist.

ORE Part 1 Dental Exam

The GDC Overseas Registration Exam Part 1 tests overseas-qualified dentists on clinically applied dental science, human disease, and clinical dentistry subjects required to practise in the UK.

100

Questions

180 min

Time Limit

50%

To Pass

Checking for saved progress...

Exam Rules

You can skip questions and return to them later
Flag questions for review before submitting
No feedback shown until you submit the entire exam
Unanswered questions count as wrong — answer everything
10 pretest questions are mixed in and don't affect your score
Timer auto-submits when time runs out
Your progress is auto-saved every 30 seconds

These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

gdc-uk.org — Retake policy, score validity, test delivery, exam dates, exam format, passing score, score release, time limit, fees · verified Oct 2026