A randomized trial of resin-based restorations in class I and class II beveled preparations in primary molars: 24-month results.

Purpose: The authors conducted a randomized clinical trial to evaluate the survival rate of esthetic restorations in Class I and Class II beveled preparations in primary molars 24 months after placement. The null hypothesis was that there is no difference among survival rates of the restorative materials used.

Methods: Forty-eight children (mean age, 5 years 9 months) received 141 restorations in beveled cavosurface margins in primary molars randomly assigned by lottery method: 46 received treatment with Vitremer Tri-Cure Glass Ionomer System (3M ESPE Dental Products, St. Paul, Minn.) (33 Class I and 13 Class II restorations), 51 received treatment with Freedom (SDI, Bayswater, Victoria, Australia) (36 Class I and 15 Class II restorations); 44 received treatment with TPH Spectrum (Dentsply, Petropolis, Rio de Janeiro, Brazil) (30 Class I and 14 Class II restorations). Two examiners whose technique had been calibrated (weight kappa > 0.85) evaluated the restorations using modified U.S. Public Health Service criteria and Visible Plaque Index score at baseline and at 12, 18 and 24 months.

Results: After two years, the authors censored data for 17 restorations, considered 101 restorations to be clinically successful and deemed 23 restorations failed because of loss of marginal integrity, anatomical form discrepancies and secondary caries. For Class I and Class II restorations, the cumulative survival rates were higher than 80 percent and 55 percent, respectively, for all materials (life table, Gehan-Wilcoxon Test, P > .05; P > .05).

Conclusions: At the 24-month clinical recall, the authors found no differences among materials in Class I (P > .05) or Class II beveled preparations (P > .05) in primary molars, but all materials showed higher survival rates in Class I than in Class II restorations.