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.