SURVIVAL OF 3 TYPES OF VENEER RESTORATIONS IN A CLINICAL-TRIAL - A 2.5-YEAR INTERIM EVALUATION

Objectives: In this clinical trial, 180 veneer restorations (VRs) were evaluated. The purpose of the study was to collect survival data and to find possible relations between survival and (1) 'type of VR', (2) 'preparation design', (3) 'operator' and (4) the patient-related varia bles 'tooth-type' and 'vitality of the tooth'. Methods: The restoratio ns were provided by seven dentists in 112 patients on central and late ral maxillary incisors. Experimental variables were: 'type of VR' (eit her direct resin composite (DC), indirect resin composite (IC) or porc elain (P)), 'preparation design' (with and without incisal overlap) an d 'operator: Failures were recorded at two levels: absolute failure (n eed for new restoration) and relative failure (need for repair). Survi val was defined at three levels: (1) survival of original restoration (S-r, endpoints: 'absolute' failures), (2) functional survival (S-f, e ndpoints: 'relative' failures) and (3) overall survival (S-o, endpoint s: both 'absolute-' and 'relative failures'). Results: The variable 't ype of VR' showed significant influence on S-f and S-o but not on S-r. S-f and S-o rates of P, IC and DC were, respectively: S-t-P, 94%; S-o -P, 94%; S-f-IC, 94%; S-o-IC, 90%; S-f-DC, 80%; S-o-DC, 74%. VRs on vi tal teeth showed a significantly better survival than VRs on non-vital teeth at all survival levels. Conclusions: Preparation of the incisal edge for incisal coverage is considered to be unnecessary to assure o r improve the strength of VRs. Veneers on non-vital teeth showed highe r risk to fail than veneers placed on vital teeth. Porcelain veneers s howed the best overall survival. (C) 1998 Elsevier Science Ltd. All ri ghts reserved.