Randomised clinical trial of Class II ART restoration in primary teeth with and without retentive grooves after 12 months.

Aim: The aim of the study was to evaluate the survival of Class II ART (Atraumatic Restorative Treatment) restorations in primary molars using encapsulated glass ionomer in cavities with and without retentive grooves. A total of 293 Class II restorations were performed on primary molars by three trained operators, using ART hand instruments (SS White/Duflex, Rio de Janeiro, Brazil) and restored with EQUIA Fil (GC Corporation, Tokyo, Japan). One hundred eighty-seven children aged 3 to 7 years (mean age = 5.5) from two public schools located in Lima, Peru, were included in the study. The restorations were performed following the ART protocol, randomising the presence or absence of proximal retentions. Cavity cleaning and restoration times were recorded by the assistant using a digital chronometer. After 6 and 12 months, evaluations occurred following the ART criteria. Data were analysed using the Mann-Whitney, Chisquare and Fisher's exact tests, Kaplan-Meier survival and logarithmic range. The mean dmf-s of the participants was 21.6 (S.D. = 10.2). The mean times to clean the cavity and apply the restorative material were 5.4 and 6.6 minutes, respectively. Success rates after 6 and 12 months for restorations without retentive grooves were 90.3% and 77.2%, respectively; and with retentive grooves 95.9% and 91.8%, respectively. Statistically significant differences were found at the 12-month follow-up (p = 0.001). The proximal retentive grooves increased the survival rate of ART Class II restorations in primary teeth after 12 months of follow-up.