[Influence of occlusal contacts of implant on adjacent teeth and antagonists displacements].

This study examined the optimum occlusal contacts of implant prostheses to maintain good oral condition after treatment. Three subjects who had two contiguously missing teeth (first and second molars) were selected. The displacement path of the implant, the adjacent tooth and the antagonistic tooth during clenching were measured using the type M-3 three-dimensional tooth displacement transducer. The occlusal contacts of implant prostheses changed according to the following four conditions. A contact: the inner inclination of the upper buccal cusp, B contact: the inner inclination of the upper lingual cusp, C contact: the outer inclination of the upper lingual cusp, and ABC contact: including the above three contacts. The measurements were performed at least six months after implant surgery. In each subject, the implants and the adjacent teeth were not affected by the change of the occlusal contact of the implant prosthesis, but the opposing teeth were affected. In the case of implantation in the lower side, the opposing tooth displaced in the buccal direction with A contact and C contact, which was a different direction to that of the natural tooth. The antagonist with B contact displaced in the lingual direction, which was the same direction as that of the natural tooth. The antagonist with ABC contact displaced in the lingual or buccal direction. It is concluded that the occlusal adjustment of implants needs much care: in the case of only A contact or C contact, non-physiological distortion might occur in periodontal tissues of the opposing teeth of the implant.