Application of Oral Implants to Tooth Splinting : A Three-dimensional Finite Element Analysis of Cases with Mandibular Bilateral Central and Lateral Incisors

[Purpose]: The purpose of this study was to examine the possibility of applying oral implants to tooth splinting in the case with 4 mandibular anterior teeth and 2 oral implants. [Materials and methods]: Five 3D finite element models of mandibular bone parts with 4 anterior teeth and an oral implant on each distal portion were constructed. The crowns on anterior teeth and the superstructures on oral implants were in contact with each other in Models A and C, and those were connected in Models B, D and E. The crowns on lateral incisors and the adjacent superstructures were connected by polyoxymethylene (POM) layer in Model E. The bone parts of Models C, D and E were lower in height than the other models by 5.5 mm. Linear static analysis was carried out under the perpendicular loading. [Results]: The maximum von Mises stress around the implant bodies were bigger in Models B and D than in Models A and C, respectively. Von Mises stress around the teeth decreased when the crowns and superstructures were bonded together. The mechanostat theory suggested bone resorptions around the implants in Models D and disuse atrophy of the tissue around the teeth in Models B, D and E. The stress values around implants were smaller in Model E than in Model D. [Conclusions]: The finite element model in which natural teeth and oral implants are connected with POM inserts is considered to be the most appropriate among the tooth-implant connected models from the viewpoint of stress values on the surrounding bone. It was supposed that a proper way for using oral implants for tooth splinting might be found under rightly controlled connecting conditions.