Stressed lawyer with cervical wear

Correct answer: B. Abfraction

• A. Abrasion is mechanical wear from a FOREIGN object — classically horizontal toothbrush abrasion, which also occurs cervically but is characteristically broad, smooth and V-shaped rather than sharply wedge-shaped.
• B. Correct. ABFRACTION is the wedge-shaped loss of tooth structure at the CERVICAL third, attributed to eccentric occlusal loading that flexes the tooth and concentrates tensile stress at the cervical fulcrum, causing microfracture of enamel rods. The combination of a high-stress occupation (parafunction/bruxism) and cervical-third loss is the classic exam presentation.
• C. Erosion is chemical dissolution by acid, producing smooth, cupped, generalised loss — typically the palatal surfaces of maxillary anteriors in GERD or bulimia, or the facial surfaces with dietary acids.
• D. Attrition is tooth-to-tooth wear, producing flattened, matching wear FACETS on OCCLUSAL and INCISAL surfaces — not cervical lesions.

Note: Abfraction versus cervical abrasion is genuinely debated in the literature and the lesions often coexist. On the exam, the STRESS/PARAFUNCTION cue points to abfraction; a HARD BRUSH / aggressive brushing cue points to abrasion.

Correct answer: B. A decrease in plaque pH

• A. Masseter hypertrophy is a recognised clinical sign of chronic bruxism/parafunction — the very habit implicated in abfraction.
• B. Correct — this is the EXCEPTION. A fall in plaque pH is the mechanism of CARIES and of acid EROSION. Abfraction is a MECHANICAL, stress-related process and has nothing to do with plaque acid production.
• C. Loss of tooth structure at the cervical third is the defining feature of the lesion itself.
• D. Dentinal hypersensitivity is a common symptom, because the lesion exposes dentinal tubules at the cervical region.