Estudo prospectivo de falhas biomecânicas em próteses totais fixas implantossuportadas : série de casos

Abstract

Complications and failures in implant supported fixed dentures (ISFD) can be related to several biological and mechanical factors, such as maximum bite force (MBF), design of the infrastructure, thickness of the aesthetic coating over metal framework and nocturnal bruxism. The aim of this case series study was to describe the failures of ISFD regarding the characteristics of aesthetic coating thickness, bite force and the presence of nocturnal bruxism. Seventeen patients who received ISFD were followed over a period of 6 to 12 months. Data were collected through anamnesis questionnaires, clinical examinations, MBF measurements and recording of the distribution of occlusal forces on the dental arch during centric and eccentric movements (protrusion and laterotrusion). The presence of bruxism was assessed by questionnaires, clinical examination and BiteStrip® device. Complications were observed in 4 patients, of which three individuals had avulsion of an artificial denture tooth while a small tooth fracture was located adjacent to the screw access hole in the other case. The findings suggest that failures caused by artificial tooth avulsion may have occurred mainly due to lack of internal retention provided by metal extensions of infrastructure. The fracture adjacent to the screw access hole was probably due to excessive opening on the resin tooth. Further studies with larger sample size and longer clinical follow-up are necessary to determine the possible risk factors for biomechanical failure of ISFD due to occlusal overload and / or design of the infrastructure.