Stress and Strain Distribution Patterns in Bone around Tissue- and Bone-Level Implant-Supported Mandibular Overdentures Using Three-Dimensional Finite-Element Analysis.

Our aim is to investigate the effect of implant placement in two positions (bone level and tissue level) on stress and strain distribution around mandibular implant overdentures. We use two models of mandibular overdentures. Taper implants are inserted and collimated between the lateral and canine teeth. All structures are scanned, digitized, and three-dimensioned (3D) model designed. We apply a vertical load of 100 N simultaneously on the central fossa of the mandibular first molar of the two models (bone- and tissue-level implant). Stress and strain values are obtained using 3D finite-element analysis (FEA). In comparison to the tissue-level model, bone-level implants can reduce overdenture movement and tension by 0.8 mum. The results of this study show that using bone-level implants can reduce tension on the prosthesis part of the overdenture and the bone around the implants as well as on the movement of the distal end of the mandibular overdenture. We found that bone strain occurred around implants within physiological limits in model 1 (bone level) compared to model 2 (tissue level). This shows that the distribution of physical forces in bone-level implants generally produces better results than those of issue-level implants. However, more research on the subject is needed.