Regarding abfraction lesions, all of the following contribute to their development EXCEPT one. Which is the EXCEPTION?

Correct answer: C. Decreased plaque pH at the cervical region

• A. Parafunctional habits (bruxism, clenching) generate excessive occlusal forces that amplify tooth flexure and accelerate abfraction development.
• B. Occlusal stress and tooth flexure are the PRIMARY mechanism — during lateral loads, the tooth bends at the cervical region, causing tensile stress that fatigues and fractures enamel.
• C. CORRECT. Decreased plaque pH causes EROSION/DEMINERALIZATION of enamel — this is the mechanism of CARIES and acid erosion, not abfraction. Abfraction is a mechanical/biomechanical process involving fatigue fracture of enamel from occlusal forces. While low pH may complicate the lesion by overlapping erosion, it is NOT a contributing factor specifically to abfraction.
• D. The enamel at the CEJ is very thin (near-zero thickness) and most vulnerable to fatigue fracture from flexure — a key anatomical factor in abfraction initiation.