A patient with bruxism who wears a hard occlusal splint is examined. What enamel finding is most likely?

Correct answer: C. Craze lines (cracked lines) in the enamel

• A. Enamel hypoplasia is a DEVELOPMENTAL defect from a disturbance during amelogenesis — present since eruption, not acquired from grinding.
• B. White spot lesions are demineralisation from plaque stagnation, characteristically around orthodontic brackets or along the gingival margin. They are unrelated to parafunction.
• C. CORRECT. CRAZE LINES are fine, shallow cracks confined to enamel, running vertically on the facial surfaces or along the marginal ridges. They are extremely common in bruxers because repetitive occlusal loading generates tensile stresses that exceed the fracture toughness of enamel. They do not cross the dentino-enamel junction, do not catch an explorer, do not cause symptoms, and require no treatment — but they need to be distinguished from a true cracked tooth.
• D. Cervical caries reflects plaque and diet, not occlusal loading. Abfraction lesions can relate to occlusal stress but are wedge-shaped non-carious defects, which is a different entity.

Note: Distinguishing craze lines from a cracked tooth: craze lines are enamel-only, asymptomatic, and transilluminate fully. A true crack extends into dentine, causes pain on release of biting pressure, and stops transillumination at the fracture line.