مرکز منطقه ای اطلاع رساني علوم و فناوري - Evaluation of the stress on attachments of mandibular two-implant overdenture

Abstract :

Objectives: The aim of this study was to evaluate the effect of implant locations on the stress around the two different attachment systems in mandibular two-implant overdentures. Materials and Methods: The data obtained from Visible Human Project were modified with the use of VRMESH and Rhinoceros 4.0 software to establish a 3D mandible model with 2 mm cortical bone covering the trabecular bone and 2 mm mucosae. 3D models (totally 6 models) of mandibular two-implant overdenture were designed according to different implant locations [lateral-lateral (LL), lateral-canine (LC), lateral-first premolar (LP)] and attachment systems [ball (BA), locator (LA)]. Foodstuff was used for occlusal loading (100N) and to simulate different biting configurations, foodstuff was positioned on incisors (anterior) and between the second premolar and first molar (posterior) bilaterally. The finite element analysis was performed by ALGOR FEMPRO software and von Mises stresses on attachments were evaluated. Results: For symmetric configuration (LL), there was more von Mises stress on BA compared to LA when foodstuff was positioned posteriorly. For asymmetric configurations (LC and LP), when the implant in the asymmetric side was positioned more posteriorly, von Mises stresses increased on both BA and LA of the implant positioned in the opposite side. In LC configuration, on BA higher von Mises stresses detected when compared to LA, whereas in LP configuration the higher stresses determined on LA when foodstuff was positioned posteriorly. Conclusions: In LL and LP configurations, LA showed lower stresses, which should lead the clinician to choose the appropriate attachment system according to the individual clinical situation.