Preparations for porcelain laminate veneers in general dental practice.

Objective: To investigate variations in preparations for porcelain laminate veneers (PLVs) in general dental practice.
Design: Laboratory-based retrospective analysis of dies for PLVs.
Setting: General dental practice in England and Wales (1994).
Methods: A sample (95 cases) of laboratory models from general dental practice featuring preparations for PLVs was randomly selected from a full service commercial dental laboratory. Aspects of the preparations were quantified and compared with accepted preparation criteria distilled from a review of the literature.
Results: The teeth found to be most frequently prepared for PLVs were maxillary incisors (48%). The majority of cases investigated were for one veneer only (56%). The margins of the preparations were variably positioned with more than half of the preparations (55%) having no clear margin. In accordance with current guidelines the incisal edge tended to have been reduced during preparation (47%). In contrast, most teeth were underprepared with an average depth of preparation of 0.16 mm (SD 0.60 mm, 95% CI-0.1, 0.42).
Conclusions: There was little evidence that established guidelines for the preparation of teeth for PLVs had been applied in full.