Finite element method analysis of occlusal splint therapy in patients with bruxism

Abstract

Background: In general, habits such as bruxism are contributory factors for temporomandibular joint (TMJ) disorders and its etiology is still controversial. Methods: Three-dimensional models of maxilla and mandible and teeth of 37 patients and 36 control subject were made using in-vivo image data. The maximum values of stress and deformation were calculated in 21 patients six months after using a splint and compared with the initial conditions. Results: The maximum stresses in the jaw bone and head of mandible in patients were 4.4 and 4.1 times higher than those in control subjects, respectively. Similar values for deformation were 5.8 and 4.9, respectively. Six months after splint application, the maximum stress in the jaw bone and head of mandible decreased by up to 71.0% and 72.8%, respectively. Similar values for the maximum deformation were 80.7% and 78.7%, respectively. With occlusal splint therapy, the approximation of the maximum deformation to the relevant values in control subjects was about 2.6 times the approximation of maximum stress to the relevant values in control subjects. The maximum stress and maximum deformation occurred in all cases in the head of the mandible and the splint had the highest effectiveness in jaw bone adjacent to the molar teeth. Conclusions: Splint acts as a stress relaxer and dissipates the extra generated stresses and especially the deformation and deviations of TMJ due to bruxism. The splint also makes the bilateral and simultaneous loading possible and helps with the treatment of this disorder through regulation of bruxism by creating a biomechanical equilibrium between the physiological loading and the generated stress.