Stress Analysis for Different Designs of Implant-borne and Tooth-implant Fixed Partial Dentures in Mandibular Posterior Region

The utilization of fixed partial dentures (FPD) ceramic frameworks for replacing the missing posterior teeth is observed to have reported high failure rates. For this reason, 3-units FPD are designed and used extensively in the clinical practices, particularly for posterior mandibular region. The current study however, aims to carry out an evaluation of different stress patterns that are induced in a 3-units FPD within posterior part of mandible using finite element analysis (FEA).Different modalities of the implant-supported FPDs such as type of connector, length and diameter of implants were taken into account. A three-dimensional (3D) model simulation of a mandibular Kennedy class II removal partial denture (RPD) was designed from a computerized tomography (CT) input with digital imaging communication on medicine (DICOM) format. In addition, occlusal load of 100 N was also used for central fossae of first premolar, first molar and second molar of the 3-units' reconstruction for each model. The magnitude of von Mises stress including minimum stress, maximum stress and average stress were also evaluated for each loading condition.The findings of the current study showed evidence that tooth-implant design with a nonrigid connector has significantly increased the average stress. Furthermore, it was observed that rigid connector has considerably minimized the stress within the tooth-implant-supported FPD.The study concluded that stress designs significantly influence the stress distribution around the bone.This study gives some guidance and criteria for the selection of the type of fixed implant prosthesis in the posterior mandibular region.