A redução do tempo de condicionamento ácido da dentina aumenta a sobrevida de restaurações em dentes decíduos? Ensaio clínico randomizado

Abstract

A randomized clinical trial was conducted to evaluate the effect of shortening the dentin acid etching time on the survival of composite resin restorations in primary teeth after selective carious tissue removal. Children aged 5 to 8 years presenting at least one carious lesion in the middle third of the dentin on the occlusal surface of primary molars were selected. One hundred primary molars were randomly allocated into two groups according to the etching time of the dentin substrate: time recommended by the manufacturer (15 s) or reduced time (7 s). After application of the adhesive system (Adper Single Bond Plus; 3M ESPE), the teeth were restored with a single increment of up to 4 mm of composite resin (Filtek Bulk Fill Posterior Restorative; 3M ESPE). All clinical procedures were performed at the Pediatric Dentistry Clinic of the Federal University of Santa Maria by a single operator. The restorations were evaluated after 1, 6, 12, and 18 months by a trained and calibrated examiner as per the World Dental Federation (FDI) criteria. Kaplan-Meier test was used to estimate the survival of the restorations. Cox multivariate regression analysis with shared fragility was used to evaluate the factors associated with restorative failures (p < 0.05). Differences in success rates regarding individual and tooth-level variables were not statistically significant (p > 0.05). However, the shortening of the acid etching time for dentin had a borderline association (p=0.07) as a protective factor for restoration failure when compared to those teeth acid etched by time recommended by manufacturer. Estimated survival rates of the restorations were 100%, 97.9%, 94.8%, and 84% after 1, 6, 12, and 18 months, respectively. The survival rates after 18 months were 75.7% and 91.4% when primary dentin was acid etched for 15 s and 7 s, respectively. In conclusion, the shortening of the dentin acid etching time did not influence survival of composite resin restorations placed in primary molars after selective carious tissue removal. However, there was a tendency for better clinical outcome when primary dentin was acid etched by 7s.