title: Caries risk and number of restored surfaces have impact on the survival of posterior composite restorations.
abstract: METHODS
  Cochrane Library, PubMed, the Web of Science (ISI) and Scopus.
  
  
  METHODS
  Longitudinal studies of direct class II or classes I and II restorations in permanent dentition of at least five years duration, a minimum of 20 restorations at final recall and the original datasets available were considered. Only English language studies were included. Two reviewers screened titles independently.
  
  
  METHODS
  Multivariate Cox regression method to analyse the variables of interest and hazard ratios with respective 95% confidence intervals were determined. The annual failure rate (AFR) of the investigated restorations and subgroups was calculated.
  
  
  RESULTS
  Twelve studies, nine prospective and three retrospective were included. A total of 2,816 restorations (2,585 Class II and 231 Class I restorations) were included in the analysis. Five hundred and sixty-nine restorations failed during the observation period, and the main reasons for failure were caries and fracture. Regression analyses showed a significantly higher risk of failure for restorations in high-caries-risk individuals and those with a higher number of restored surfaces. The overall annual failure rate at five years and ten years was 1.8% and 2.4% respectively. The rates were higher in high-caries-rate individuals at 3.2% and 4.6% respectively.
  
  
  CONCLUSIONS
  The conclusion of the present meta-analysis of 12 clinical studies based on raw data is that caries risk and number of restored surfaces play a significant role in restoration survival, and that, on average, posterior resin composite restorations show a good survival, with annual failure rates of 1.8% at five years and 2.4% after ten years of service.
authors.affiliation: University of British Columbia, Vancouver, Canada.
authors.forename: Ben
authors.initials: B
authors.lastname: Balevi
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000592:standards*; D006801:Humans
chemical_list: D003188:Composite Resins; D003764:Dental Materials