Mixed Deck — All MJDF Topics Flashcards

A bitewing radiograph is MOST useful for detecting which of the following?

Answer: Interproximal caries and alveolar crest bone levels

Bitewing radiographs are specifically designed to show the crowns of upper and lower teeth simultaneously, making them ideal for detecting interproximal caries and assessing the alveolar crest height.

What is the trigeminal nerve's sensory distribution relevant to dental anaesthesia, and which division supplies the mandibular teeth?

Answer: The mandibular division (V3) supplies the mandibular teeth via the inferior alveolar nerve; V2 (maxillary) supplies the maxillary teeth; V1 (ophthalmic) supplies the forehead and upper face

The trigeminal nerve (CN V) has three divisions: V1 (ophthalmic) supplies sensation to the forehead, upper eyelid, and nose dorsum; V2 (maxillary) supplies the mid-face, maxillary teeth (via posterior, middle, and anterior superior alveolar nerves), and palate (via greater and lesser palatine and nasopalatine nerves); V3 (mandibular) supplies the lower face, mandibular teeth (via the inferior alveolar nerve), lower lip and chin (mental nerve), tongue (lingual nerve — general sensation), and buccal mucosa (long buccal nerve). V3 is the only division with motor fibres (muscles of mastication).

Why is aspirin contraindicated as a post-operative analgesic for dental extractions?

Answer: Irreversibly inhibits platelet COX-1, preventing thromboxane A2 synthesis and impairing clotting for platelet lifespan (7–10 days)

Aspirin irreversibly acetylates platelet COX-1, eliminating thromboxane A2-mediated platelet aggregation for the platelet's entire lifespan, significantly increasing post-extraction bleeding risk.

Class II Division 2 malocclusion is most characteristically associated with which combination of features?

Answer: Retroclined upper central incisors, deep overbite, and increased curve of Spee

Class II Division 2 is distinguished by retroclined upper central incisors, a markedly deep overbite, and an increased curve of Spee, often on a mild Class II or Class I skeletal base.

What does the term 'apical transportation' refer to in root canal treatment?

Answer: Iatrogenic alteration of the original canal path, causing the foramen to be moved away from its original position

Apical transportation (also called apical 'zipping' or 'elbow formation') is an iatrogenic procedural error where the apical foramen is displaced from its original position due to excessive straightening of curved canals.

What is the primary aim of the UK Government's 'Smile4Life' oral health improvement programme?

Answer: Improve oral health of vulnerable adults (learning disabilities, mental health issues, older adults) through accessible, person-centred care

Smile4Life is a national framework for improving the oral health of vulnerable adults in Scotland, addressing the significant oral health inequalities experienced by people with learning disabilities, mental health conditions, and older care home residents.

What is the dental significance of a patient being HIV-positive and what oral manifestations may be seen?

Answer: HIV-positive patients may present with oral candidiasis, oral hairy leukoplakia, Kaposi's sarcoma, necrotising ulcerative gingivitis/periodontitis, linear gingival erythema, recurrent aphthous ulceration, and HPV-related lesions; these may be the first signs of HIV infection or indicate disease progression and falling CD4 count

Oral manifestations of HIV are common and may be the presenting feature of undiagnosed HIV infection. Key oral lesions include: pseudomembranous and erythematous candidiasis (most common, especially when CD4 <200), oral hairy leukoplakia (EBV-related, lateral tongue), Kaposi's sarcoma (HHV-8 related, violaceous patches/nodules on palate/gingiva), necrotising ulcerative gingivitis/periodontitis (rapid destruction), linear gingival erythema (band-like erythema along gingival margin), major aphthous ulceration, and HPV-associated papillomas/warts. HAART (highly active antiretroviral therapy) has significantly reduced the prevalence of these lesions. Standard infection control is sufficient for dental treatment — no additional precautions beyond universal precautions are needed.

What is the effective dose from a dental bitewing radiograph (digital) compared to background radiation?

Answer: Approximately 1–8 µSv per image; background radiation is approximately 2,700 µSv/year in UK

A digital bitewing delivers approximately 1–8 µSv (depending on technique), representing a very small fraction of the average UK background radiation of approximately 2.7 mSv/year; this context aids risk communication with patients.

Which region of the pulp contains the highest density of nerve endings?

Answer: Sub-odontoblastic plexus of Raschkow

The plexus of Raschkow, located just below the odontoblast layer in the coronal pulp, contains a dense network of unmyelinated C-fibres and myelinated Aδ fibres responsible for pain perception.

A patient with Sjögren's syndrome presents with xerostomia and multiple cervical caries. What is the underlying pathology and how should the dental management be tailored?

Answer: Sjögren's syndrome involves autoimmune destruction of salivary (and lacrimal) glands, reducing salivary flow; dental management includes frequent fluoride application (5000 ppm toothpaste, fluoride varnish), saliva substitutes/stimulants, sugar-free diet counselling, and regular short-interval recall appointments

Sjögren's syndrome is an autoimmune condition where lymphocytic infiltration destroys salivary and lacrimal glands, causing xerostomia and keratoconjunctivitis sicca. Reduced saliva eliminates its protective buffering, antimicrobial, and remineralising functions, leading to rampant cervical and incisal caries. Dental management: prescribe 5000 ppm fluoride toothpaste, apply fluoride varnish quarterly, recommend saliva substitutes (containing fluoride and calcium) and stimulants (sugar-free gum, pilocarpine if severe), counsel on sugar avoidance, use GIC restorations for fluoride release, and schedule 3-monthly recalls. Monitor for oral candidiasis and parotid gland swelling.

What antibiotic prophylaxis is currently recommended for dental procedures in patients at risk of infective endocarditis in the UK?

Answer: No routine antibiotic prophylaxis — NICE guideline NG64 no longer recommends prophylaxis for dental procedures

NICE guideline NG64 (updated) advises that antibiotic prophylaxis is not routinely recommended for dental procedures in at-risk patients; excellent oral hygiene is emphasised instead.

When assessing a patient for a fixed dental prosthesis (bridge), what is Ante's Law and what is its clinical significance?

Answer: It states that the total periodontal ligament area of the abutment teeth should be equal to or greater than that of the teeth being replaced — it helps determine whether abutment teeth can support the bridge

Ante's Law (1926) states that the total root surface area (periodontal ligament area) of the abutment teeth must be equal to or exceed that of the teeth to be replaced by pontics. This ensures the abutment teeth can support the additional occlusal load. While widely taught, it is considered a general guideline rather than an absolute rule — clinical factors such as crown-to-root ratio, bone support, occlusion, and abutment tooth condition also influence treatment planning.

What is the main disadvantage of zinc oxide eugenol as a temporary cement?

Answer: Eugenol inhibits polymerisation of resin composites — cannot be used under composite restorations

Residual eugenol from ZOE cements inhibits free-radical polymerisation of composite resins; if ZOE is used as a temporary restoration or liner, eugenol contamination prevents composite bonding and curing.

What is the most common site for oral cancer in the UK?

Answer: Lateral border of the tongue

The lateral border and ventral surface of the tongue is the most common site for oral squamous cell carcinoma in the UK, accounting for approximately one-third of all cases.

What cone beam CT (CBCT) field of view (FOV) is recommended for implant planning?

Answer: Limited FOV (5 × 5 cm or 8 × 8 cm) focused on the implant site — minimises dose while providing accurate measurement

ALARP requires the smallest FOV that provides the required diagnostic information; limited FOV CBCTs (5 × 5 or 8 × 8 cm) are recommended for implant site assessment, significantly reducing dose compared to large FOV scans.

What is the recommended protocol for managing an avulsed permanent incisor in a 10-year-old child who presents within 30 minutes of the injury with the tooth stored in milk?

Answer: Replant the tooth immediately: rinse gently with saline (do not scrub the root surface), replant into the socket, apply a flexible splint for 2 weeks, prescribe antibiotics and tetanus check, begin root canal treatment 7-10 days post-replantation

According to the International Association of Dental Traumatology (IADT) guidelines, for an avulsed permanent tooth with a closed apex, replanted within 60 minutes with the tooth stored in appropriate medium (milk, saline, Hank's balanced salt solution): gently rinse the root surface with saline (do not scrub or remove attached PDL cells), replant into the socket, apply a flexible (passive) splint for 2 weeks (using orthodontic wire and composite), prescribe systemic antibiotics (doxycycline 100mg or amoxicillin if under 12), verify tetanus immunisation, and initiate root canal treatment 7-10 days post-replantation (before splint removal) to prevent inflammatory resorption.

What is the primary radiation protection advantage of using a rectangular collimator instead of a circular one for an intraoral periapical radiograph?

Answer: It significantly reduces the patient's effective dose.

Rectangular collimation restricts the size of the X-ray beam to more closely match the dimensions of the rectangular image receptor. This reduces the volume of patient tissue irradiated, which can lower the effective radiation dose by 40-60% or more compared to a standard circular collimator. While it may increase the risk of 'cone-cutting' errors if not aligned correctly, its dose-saving potential is a key principle of radiation optimisation (ALARP).

What is the most likely diagnosis when a patient presents with multiple painless cervical lymphadenopathy and persistent oral ulcers not healing after 3 weeks?

Answer: Oral squamous cell carcinoma until proven otherwise — urgent 2-week wait referral required

Persistent oral ulceration exceeding 3 weeks with cervical lymphadenopathy raises strong suspicion for oral malignancy; urgent referral via the 2-week wait pathway is mandatory.

What is the biological mechanism by which dentine hypersensitivity is explained by the hydrodynamic theory?

Answer: Fluid movement in dentinal tubules triggers mechanoreceptors at the pulp-dentine boundary

Brannstrom's hydrodynamic theory proposes that stimuli (cold, touch, osmosis) cause rapid dentinal fluid movement, which activates Aδ fibres at the pulp-dentine boundary, producing a sharp pain response.

What is the recommended total occlusal convergence angle for a full-coverage crown preparation to achieve optimal retention and resistance form?

Answer: 6–12 degrees

A total occlusal convergence of 6–12 degrees provides the best balance between retention (favouring more parallel walls) and the clinical practicality of seating the crown without binding. Angles above 20 degrees significantly reduce retention and resistance form; truly parallel preparations (<3 degrees) are difficult to achieve clinically and risk undercut.