Veneer Debonding Cause — ORE Part 1 MCQ

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ModerateDental MaterialsVeneer Debonding CauseORE Part 1

A porcelain veneer on the upper left lateral incisor has debonded repeatedly. More than half of the labial surface is occupied by an existing composite restoration. Which factor most likely accounts for the repeated debonding?

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Correct answer: E — Insufficient enamel available for bonding

Explanation lettering: B = shown as A · C = shown as B · D = shown as C · E = shown as D · A = shown as E

A is correct. Reliable ceramic veneer bonding depends principally on a substantial enamel substrate. Here, the extensive labial composite means that much of the veneer is supported by an existing restoration rather than etched enamel, making loss of retention more likely. Clinical evidence shows markedly poorer veneer survival where bonding involves dentine rather than enamel; preservation of enamel is therefore a key determinant of predictable adhesion. B may contribute to fracture risk or contour problems, but does not explain the substrate-specific pattern. C would be relevant if it had exposed dentine, but excessive preparation depth is not stated; the decisive fact given is extensive existing composite. D has no effect on retention. E can contribute to failure where there is parafunction or an adverse occlusal scheme, neither of which is described, and it is less strongly indicated than the compromised bonding substrate.

Reference: Gurel G, Sesma N, Calamita MA, Coachman C, Morimoto S. Influence of enamel preservation on failure rates of porcelain laminate veneers. International Journal of Periodontics & Restorative Dentistry. 2013. https://pubmed.ncbi.nlm.nih.gov/23342345/