The Cochrane Library, Medline, Embase, and Web of Knowledge databases were searched and the Evidence-Based Dentistry, International Journal of Prosthodontics, Journal of Prosthetic Dentistry, Journal of Adhesive Dentistry, Journal of Esthetic and Restorative Dentistry, and Journal of Oral Rehabilitation were hand searched. Clinical trials registers, conference proceedings and academic colleagues were contacted to identify unpublished data, abstracts and other gray literature. There were no language limits.
Article identification, screening, and eligibility and inclusion assessments were completed independently by two reviewers. Prospective and retrospective cohort and controlled trials assessing the outcome of feldspathic porcelain veneers in more than 15 patients were included. Some veneers in each study had to be in situ for five years. Veneers placed using unusual techniques, such as with no enamel preparation or excessive incisal edge lengthening, were excluded.
Data extraction and synthesis
Estimated cumulative survival and standard error for each study were assessed and used for meta-, sensitivity and post hoc analyses. The I2 statistic and the Cochran Q test and its associated P value were used to evaluate statistical heterogeneity, with a random-effects meta-analysis used when the P value for heterogeneity was less than 0.1. Heterogeneity, publication patterns and small study biases were explored.
Eleven studies were included with six (four prospective and two retrospective cohorts) contributing to the meta-analysis. The estimated cumulative survival for feldspathic porcelain veneers was 95.7% (95% confidence interval [CI]: 92.9% to 98.4%) at five years and ranged from 64% to 95% at ten years across three studies. A post hoc meta-analysis indicated that the 10-year best estimate may approach 95.6% (95% CI: 93.8% to 97.5%). High levels of statistical heterogeneity were found.
When bonded to enamel substrate, feldspathic porcelain veneers have a very high 10-year survival rate that may approach 95%. Clinical heterogeneity is associated with differences in reported survival rates. Use of clinically relevant survival definitions and careful reporting of tooth characteristics, censorship, clustering, and precise results in future research would improve meta-analytic estimates and aid treatment decisions.