Mechanical Effects of Implant Position on an Implant-Supported Removable Partial Denture Using Three-Dimensional Finite-Element Analysis.

Abstract

<h4>Purpose</h4>This study aimed to assess the mechanical effects of different implant placement positions for removable partial dentures using the three-dimensional finite-element method.<h4>Methods</h4>A mandibular model with missing teeth at sites #35, #36, #45, #46, and #47 was utilized for the simulation. The basic model was designed as a removable partial denture with "Rest, Proximal plate, I-bar" clasps on teeth #34 and #44, with tooth #37 serving as an overdenture abutment featuring a magnetic attachment. For comparison, three implant-supported models were constructed, each incorporating a 10.0 mm implant placed at the edentulous posterior site #45, #46, or #47.<h4>Results</h4>Stress analysis revealed several mechanical effects in the implant-supported models compared with the basic model. First, the stress of the abutment tooth structures around tooth #44 decreased. Second, the stress distribution to the residual ridge mucosa also decreased. Furthermore, displacement of the denture base was markedly reduced, with smaller displacements observed at sites closer to the implant site. Among the three implant models, the model with an implant at position #46 exhibited the least displacement.<h4>Conclusions</h4>These findings suggest that implant placement of distal-extension removable partial dentures may reduce the mechanical load on the abutment tooth and surrounding tissues, reduce denture movement, and potentially provide an additional support area for removable partial dentures.