Shortening of etching time of the dentin in primary teeth restorations: a randomized clinical trial

Abstract The aim of this study was to investigate the influence of shortening of etching time for dentin on the restoration survival after selective carious tissue removal in primary molars. This two-arm randomized clinical trial included sixty-two subjects (5–8 year-old) and 100 primary molars presenting moderate dentin carious lesions on occlusal surface. The sample was randomly assigned into groups previously to adhesive application (Adper Single Bond 2; 3M ESPE): etching time recommended by manufacturer (15 s) or reduced (7 s). Resin composite (Filtek Bulk Fill Posterior Restorative; 3M ESPE) was inserted in a single increment for all restorations. Restorations were evaluated at 1, 6, 12, and 18 months using FDI criteria. Survival estimates for restorations’ longevity were evaluated with Kaplan-Meier method. Multivariate Cox regression analysis with shared frailty was used to assess the factors associated with failures (p