Variations in the depth of preparations for porcelain laminate veneers

The reflex metrograph was used to measure preparation depth for a sample (21) of preparations for porcelain laminate veneers obtained from a large commercial laboratory. Eight (38%) of the teeth investigated were found to be unprepared with 13 (62%) teeth prepared to varying degrees. Five (24%) of the teeth were over prepared with the depth of two preparations exceeding 1.0 mm. There was little evidence that widely advocated guidelines for the preparation of teeth for porcelain laminate veneers had been used. The effect of dentine exposure on the clinical longevity of porcelain laminate veneers remains to be investigated.