ORE Part 1 Oral Biology & Pathology

Question 1

What is the major inorganic component of dental enamel?

Accepted Answer

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

Answer

Calcium phosphate only

Answer

Collagen

Answer

Fluorapatite

Question 2

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

Accepted Answer

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

Answer

Single bacterial infection without diet involvement

Answer

Fluoride deficiency alone

Answer

Genetic susceptibility alone

Question 3

What is the histological appearance of the 'resting line' in cementum?

Accepted Answer

Dark lines (incremental lines) representing periods of reduced cementogenesis, similar to von Ebner lines in dentine

Answer

The CEJ between enamel and cementum

Answer

Cracks caused by occlusal loading

Answer

Areas of secondary cementum deposition

Question 4

Which cells are responsible for dentine formation?

Accepted Answer

Odontoblasts

Answer

Ameloblasts

Answer

Cementoblasts

Answer

Osteoblasts

Question 5

What is 'scalloped' basement membrane in the gingival epithelium?

Accepted Answer

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

Answer

The CEJ morphology

Answer

The scalloped gingival margin shape

Answer

The attachment of junctional epithelium to enamel

Question 6

What is the role of salivary immunoglobulin A (IgA) in oral defence?

Accepted Answer

Provides mucosal immunity by binding antigens and preventing bacterial adherence to oral surfaces without invoking complement

Answer

Acts as an opsonin for phagocytosis

Answer

Neutralises bacterial endotoxins in the bloodstream

Answer

Forms antibody-antigen complexes that trigger inflammation