Mixed Deck — All MFDS Topics Flashcards

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

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.

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

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.

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?

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.

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?

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.

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

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.

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?

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.

Glass ionomer cement bonds to tooth structure primarily through:

Answer: Ionic bonding to calcium

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

What causes the 'creep' of dental amalgam restorations at amalgam margins?

Answer: Time-dependent plastic deformation under occlusal load

Creep is time-dependent plastic deformation of amalgam under sustained occlusal stress, leading to marginal overhang and ditching over time.

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?

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).

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

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.

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

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.

The most common type of odontogenic cyst is the:

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.

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

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

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

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

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.

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

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.

Carbamazepine is the drug of first choice for management of:

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.

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?

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.

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

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

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

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

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.

Erythromycin achieves its antibacterial effect by binding to the:

Answer: 50S ribosomal subunit

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