Randomised trial of resin-based restorations in Class I and Class II beveled preparations in primary molars: 48-month results.

Objective: This randomised clinical trial evaluated the survival rate of resin-based restorations in Class I and Class II beveled preparations in primary molars, over 48 months.

Methods: Forty-eight children received 141 restorations in beveled cavosurface margin preparations in primary molars randomly assigned by a lottery method: 46 received treatment with Vitremer Tri-Cure Glass Ionomer System (33 Class I and 13 Class II restorations); 51 received treatment with Freedom (36 Class I and 15 Class II restorations); 44 received treatment with TPH Spectrum (30 Class I and 14 Class II restorations). Two calibrated examiners (weight kappa> or =0.85) evaluated the restorations using the modified USPHS criteria and visible plaque index score at baseline and after 12, 24, 36 and 48 months. Cox regression with survival analysis and logistic regression evaluated the clinical performance of restorations.

Results: After 48 months, 11 teeth had exfoliated, 16 restorations were dropouts, 83 restorations were clinically successful of which 26 had used Vitremer, 32 had used Freedom and 25 had used TPH Spectrum. Thirty-one restorations failed because of secondary caries, fractures and loss of retention. The cumulative survival was 73.9%, 83.4% and 79.6%, respectively for Vitremer, Freedom and THP Spectrum with no differences among materials (Log Rank Mantel-Cox, p>0.05). However, the Class II cavity preparation reduced the survival of the restorations (OR=5.1) for all materials evaluated (p>0.05).

Conclusions: The life expectancy of Vitremer, Freedom and THP Spectrum in Class I and Class II restorations could be comparable after 48 months.