Desempenho de uma resina bulk-fill em restaurações classe II em molares decíduos – ensaio clínico randomizado

Abstract

This study consists of two studies on the use of bulk-fill resin in occluso-proximal lesions of primary molars. The use of bulk-fill resin in increments up to 4 mm thick, provides that restorations on primary teeth can be made with a single increment. Reduction on the number of steps, restorative time, and technical simplification are desired advantages, especially in Pediatric Dentistry. It is necessary that such advantages attributed to bulk-fill resin are proven and that its clinical performance is evaluated longitudinally. The aim of this study was to compare the clinical behavior of bulk fill resin and conventional resin (incrementally applied) in occluso-proximal cavities in deciduous molars after 6-month. Moreover, the time spent to restore the occluso-proximal cavities (secondary outcome). One hundred forty occluso-proximal cavities in deciduous molars in 65 participants (mean age of 6.7 + 1.5) were randomized in two groups, according to composite resin: bulk-fill (FiltekTM Bulk Fill; 3M ESPE, St. Paul, MN, USA) and conventional composite resin (Filtek Z350 XT; 3M ESPE, St. Paul, MN, USA). All restorations were made by a single trained operator, under local anesthesia, rubber dam isolation, and the removal of carious tissue followed parameters of selective carious removal to firm dentin. The cavities were measured for their depth and, buccolingual distance, and the restorative time was registered (data used in article I). A trained, calibrated, and blind examiner evaluated the restorations according to the International Dental Federation (IDF) criteria within 3 (baseline) and 6 months after restorative procedures (data used in article II). The obtained scores were analyzed considering restoration success (scores 4 and 5 as failure) or success and repair (only score 5 as failure). All data were analyzed with the Mann-Whitney U test. A significance level of 5% was considered in all analysis. The results showed that bulk-fill resin reduces restorative time by approximately 30% compared to conventional composite resin (p <0.0001). Moreover, while most of the restorations that used bulk-fill resin received a single increment, the restorations of the control group required on average, 3 increments (p <0.0001). Thus, the reduction of clinical time and the number of steps that bulk-fill resin offers in occluso-proximal lesions of deciduous molars has been demonstrated. The bulk-fill resin demonstrated satisfactory and similar clinical performance to the conventional composite resin. Most restorations received scores ranging from 1 to 3 (clinical success). The success rate of the bulk-fill resin was 94.3%, and the conventional resin was 95.7% (p = 0.7). Seven restorations failed in the evaluation of 6 months, 4 of bulk-fill resin and 3 of conventional resin. Marginal adaptation was the main cause of clinical failure (5 restorations). According to the results, bulk-fill resin presented similar clinical behavior to the conventional resin. It is an option to restore occluso-proximal lesions of deciduous molars.