Influência do protocolo restaurador no comportamento biomecânico de dentes pré-molares com lesões cervicais não cariosas e cavidade MOD: análise por elementos finitos

Abstract

The loss of dental tissue in the amelocementary region is characteristic of non-carious cervical lesions (NCCLs). Commonly in clinical practice, NCCLs are associated with MOD cavities, and improper restorative protocols can generate higher concentrations of residual stresses. The aim of this study was to evaluate, using the 3D finite element method, the contraction stresses generated during the polymerization of composite resin in restorations of premolar teeth with NCCLs and MOD cavity. This study used as a reference a three-dimensional virtual CAD (Computer Assisted Design) model of a healthy upper premolar from the LNC group's database. This CAD model (3DM) has dimensions and anatomy favorable and according to the literature average, representing the coronal anatomy of dentin, pulp, enamel, and restorations (NCCL and MOD). Four models were processed according to the MOD restorative sequence and restorative technique: 1- 1st NCCL Restoration and 2nd MOD Restoration with incremental technique; 2- 1st NCCL Restoration and 2nd MOD Restoration with bulk-fill technique; 3- 1st MOD Restoration with incremental technique and 2nd NCCL Restoration; and 4- 1st MOD Restoration with bulk-fill technique and 2nd NCCL Restoration. After model processing, the results of residual contraction stresses were plotted by Modified Von Mises criteria. It was concluded that the incremental technique generated higher values of residual contraction stress regardless of the restorative sequence, and the restorative sequence did not affect the residual contraction stress, but the restoration of NCCL before the MOD cavity generated lower stress peaks during the procedure.