Distribuição de tensões radiculares variando a conicidade e calibre de instrumentos endodônticos mecanizados e cargas oclusais - análise de elementos finitos

Abstract

Chemical-mechanical preparation is one of the most important endodontic stages, and for this purpose many instrumentation techniques have been suggested in recent years. Currently, there are many mechanized instruments, both reciprocating and rotating, and much has been discussed about dentin wear due to preparation and dentin resistance. The aim of this research was to evaluate the tension generated in dental element after endodontic preparation performed with files of different calibers and tapers in occlusal loads. For this purpose, beyond the healthy control model, simulations of endodontic preparations were performed on another six identical 3D models of a lower second premolar, with configuration files # 30/.05, # 30/.09, # 35/.04, # 35/.06, # 40/.04 and # 40/.06. The elements and nodal points of the models ranged from 15.706-17.452 and 24.958-28.757 respectively, with von-Mises equivalent stress applied at 30 N, 90 N, 270 N and 810 N stresses, each with load incidence at 20º, 45º and 90º of occlusal plane simulating laterality, dental interference and occlusion, respectively. The results indicated that the caliber and taper of the instruments were not capable of generating larger areas of maximum tension in the dental structure. Also, oblique loads were more prone to formation of higher stress points when compared to forces at vertical incidence. Therefore, it is concluded that dentin wear is not the only factor for increased dental susceptibility to the development of dental fracture.