Desempenho de restaurações diretas em dentes posteriores: efeito da técnica restauradora, do tipo de material e do perfil do profissional

Abstract

Composite resins have been considered material that provide adequate mechanical resistance with optimal clinical longevity when used in direct restorations for vital or endodontically treated posterior teeth. This study aimed to evaluate the in vitro and clinical performance of direct restorations in endodontically treated and molar teeth and also the longevity of posterior restorations, amalgam or composite resin restorations, performed in public service. Four objectives integrated this study: Objective 1: to investigate the effect of total and post-gel shrinkage calculated experimentally on the shrinkage stress of composite resins in endodontically treated molars using two-dimensional finite element analysis. Objective 2: To investigate the biomechanical behavior of direct composite resin restorations in endodontically treated molar teeth by means of a laboratory test, cusp deformation measured by strain-gauge test, fracture resistance and failure modes calculated by axial compressive load test after fatigue and the presence of bubble formation and porosities measured by micro-CT. Objective 3: To evaluate, by using randomized clinical trial the behavior of class II restorations in 56 molars treated endodontically with bulk fill resin compared with incremental technique after two-year follow-up. Objective 4: To evaluate retrospectively the longevity of posterior almalgam or composite resin restorations, performed in the oral health public service of Uberlândia, MG. It can be concluded that the total shrinkage resulted in greater stress concentration in the enamel and root dentin near the pulp chamber when compared to the values of calculated using post-gel shrinkage. It was also found that tested resins have different rankings regarding the total and post-gel shrinkages. The porosity in the restorations had no influence on cusp deformation, fracture resistance and fracture modes. The use of resin-modified glass ionomer to fill the pulp chamber associated with incremental composite resin restoration resulted in similar biomechanical performance that regular viscosity or flowable bulk fill resin restorations. The incremental technique associated with glass ionomer inserted in the pulp chamber performed similarly to the bulk fill regular viscosity composite resin resin after 2 years. The bulk fill resin presented slightly superior performance for the marginal adaptation and surface texture outcomes. The amalgam and composite resin posterior restorations performed in the public health service of Uberlândia, has high survival rate, being influenced by the geographical area in which they were performed. Restorations performed in patients with lower social indicators had lower survival rates. The general context of this study demonstrated good performance of direct restorations in posterior teeth in both senarios when the mechanical aspects was tested usinh in vitro studies, as well as in clinical trials and practice-based analysis in public service.