METAANALYSIS OF ANTERIOR VENEER RESTORATIONS IN CLINICAL-STUDIES

Objectives: To make an inventory of clinical studies on veneer restora tions (VRs) using a meta-analysis review procedure and to aggregate an overall survival result for four types of VRs. Methods: From the dent al literature published from 1983 to November 1996, papers were select ed using an in-and exclusion protocol in a two-step procedure. Additio nally, the papers selected were subjected to a quality assessment. Alt hough not all studies used an identical definition of 'failure of a re storation', this item was chosen to be the common study outcome. After a homogeneity test, cumulative survival curves were constructed by po oling the data from the studies. Results: On a 0-1 scale, the weighted overall mean quality score of the studies was 0.57 (s.e. 0.09). There was adequate agreement between the independent assessors. The results of the quality assessment could not be used as weights for the surviv als, but the quality outcome supports the description of the sample of studies. From the nine studies on porcelain VRs, the pooled cumulativ e proportion of survival after 3 years was 0.92 (s.e. 0.01) and from t hree studies on preformed acrylic VRs this figure was 0.74 (s.e. 0.03) . From both direct and indirect resin composite VRs, data from only on e study were available after 2.5 and 2 years, respectively. Conclusion : The evaluative and statistical basis of clinical VR studies may be i mproved to obtain an effective inference of the results. Furthermore, porcelain VRs show acceptable longevity after 3 years, which appears t o be better than that of preformed acrylic VRs.