Multicenter RCT Shows How to Increase the Survival of ART Restorations

Objectives: To evaluate the survival rates of ART Class II restorations in primary molars performed with and without proximal retentions in 2 centers in Brazil (Bauru and Brasília) and 1 in Peru (Lima).
Methods: This study enrolled children with good health, aged 4 to 7 years (mean age = 5.53) who had at least one Class II cavity in a primary molar and whose parents signed the informed consent form. The selected cavities were randomly allocated into two groups: ART protocol (G1) ART protocol plus retentive grooves in the buccal and lingual walls of the proximal box, performed with a hand excavator (G2). Randomization was carried out considering the extent of the cavity proximal ridge (A- restricted to the contact area; B- one side - buccal or lingual - extending over the proximal ridge; C- both lingual and buccal extending the proximal ridges) and the dmfs of the child. A total of 881 Class II restorations were performed by trained operators in each center, using hand instruments for ART (SS White / Duflex, Rio de Janeiro, Brazil) and restored with Equia Fil (GC Corporation, Tokyo, Japan). Calibrated examiners evaluated the restorations after 12, 24 and 36 months (Kappa intra- and inter-evaluators > 0.80). Statistical analysis was performed using Chi-square, Kaplan-Meier, Log-rank and univariate Cox regression analysis.
Results: The success rates after 12, 24 and 36 months were: 79.6%, 74.0% and 70.4, respectively for G1, and 84.1%, 81.8% and 77.5%, respectively for G2. The observed data showed statistically significant differences between groups for 12, 24 and 36 months (p<0.001).
Conclusions: Proximal retentive grooves in primary molars showed increased survival rates of ART Class II restorations.