Meta-analysis on long-term clinical performance of posterior composite restorations.

Meta-analysis is a formalized method of combining results of different studies to provide conclusions about the effectiveness of a treatment modality. The aims of this study were to use meta-analysis to determine the clinical performance of posterior composite restorations using the assessment criteria of the USPHS guidelines by combining data from selected multiple studies and to estimate the overall survival rates of posterior composite restorations over time. A computer-aided search of the literature revealed 97 publications on clinical trials of posterior composites in the last 10 years. Following specific selection criteria, which included the year and language of publication, duration of study, class of cavities restored and type of resin composite material used and clinical characteristics assessed; 16 studies were found to be suitable for, and included in a meta-analysis. These involved eight different resin composite materials. Assessment criteria data were extracted from each selected study and tabulated on the basis of years of follow-up and materials. The criteria were coded as binary variables. Homogeneity amongst studies was assessed using Woolf's statistic prior to combining the data. Weighted average proportions and standard errors were determined for each of the assessment criteria. Using Kaplan-Meier estimates, survival analyses of individual assessment criteria (outcomes) for two posterior composite materials were conducted and the resultant survival curves for these outcomes for the two materials are presented. Considering the limited number of studies of variable length available for meta-analysis, the results indicate generally high clinical performance of the various posterior composites for the number of outcomes analysed.

Radiopacity of resin-based inlay luting cements.

The radiopacity of a group of seven resin-based inlay luting cements in addition to two porcelain veneer cements was determined. Four inlay cements (Indirect Porcelain System Dentist Bonding Kit, Dicor MGC, Duo, and Twinlook) were found to have radiopacity values significantly greater than the radiopacity of enamel. Two other inlay cements (Dual and Porcelite Dual Cure) were found to have radiopacity values not significantly different from that of enamel, while All-Bond Crown and Bridge cement had a radiopacity value significantly lower than the radiopacity of dentin. For the two porcelain veneer cements examined, one material (Mirage Bond) had a radiopacity value significantly greater than that of enamel, while the other (G-Cera Porcelain Veneer Bonding System) had a radiopacity value significantly lower than that of dentin. It was concluded that only the materials that have radiopacity values greater than or equivalent to the radiopacity of enamel are suitable for use as inlay cements. For porcelain veneers, a relatively high radiopacity value of the cement is advantageous.