Meta-analysis of anterior veneer restorations in clinical studies

Objectives: To make an inventory of clinical studies on veneer restorations (VRs) using a meta-analysis review procedure and to aggregate an overall survival result for four types of VRs. Methods: From the dental literature published from 1983 to November 1996, papers were selected using an in-and exclusion protocol in a two-step procedure. Additionally, the papers selected were subjected to a quality assessment. Although not all studies used an identical definition of 'failure of a restoration', this item was chosen to be the common study outcome. After a homogeneity test, cumulative survival curves were constructed by pooling 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 survivals, but the quality outcome supports the description of the sample of studies. From the nine studies on porcelain VRs, the pooled cumulative proportion of survival after 3 years was 0.92 (s.e. 0.01) and from three 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 one study were available after 2.5 and 2 years, respectively. Conclusion: The evaluative and statistical basis of clinical VR studies may be improved to obtain an effective inference of the results. Furthermore, porcelain VRs show acceptable longevity after 3 years, which appears to be better than that of preformed acrylic VRs.