The effect of various preparation designs on the survival of porcelain laminate veneers

The aim of this clinical study was to observe the service duration of porcelain laminate veneers (PLVs) and to estimate the influence of the categorical covariates such as location, tooth vitality, preparation depth, incisal, gingival and proximal finishing lines, and peripheral tissue type on the survival rates of event-free and overall service duration.

A total of forty patients (26 women, 14 men; age range: 16 to 50) who had received 200 PLVs were evaluated in this study. Median follow-up time was 67.25 weeks with a range of 12 to 72 weeks. Fifteen of the restored teeth were nonvital, while the remaining 185 were vital. Categorical covariates related to the restoration design (localization, vitality, preparation depth, incisal, proximal, and gingival finishings, and surrounding tissue type) were recorded in order to estimate their influence on the survival rates. Survival rates of the event-free and overall service duration were calculated with the Kaplan-Meier analysis and Mantel log rank test.

Twelve failures were observed. The most frequent failure type (11 units) was debonding of the restoration from the abutment tooth. Nine of them were rebonded and the remaining 2 were remade with a different preparation design. The last failure was observed as a coronal fracture at the cervical level. The overall survival rates were 99.5%, 99%, 97.5%, 94.9%, 94.4% and 93.8% at weeks 8, 9, 11, 15, 16, and 34, respectively, with a mean estimate of 68.45 weeks.

PLVs exhibited good clinical results with their conservative specifications and high survival rates. The preparation and design specifications affect the service duration of PLVs.