Aim: The purpose of this study was to elucidate time-dependent changes in occlusal status over a 3-month period to understand dynamic factors that act on implant-supported prosthesis. We used pressure-sensitive film for occlusal force diagnostics and silicone testing material to measure the occlusal status of a mandibular first molar implant-supported prosthesis under controlled clenching strengths.
Materials and methods: The subjects were eight patients who had an implant-supported prosthesis inserted at the mandibular first molar and did not have any missing teeth other than the implants. We performed the following tests immediately and 3 months after fitting the prosthesis. First, we monitored masseter muscle activity and defined maximum clenching strength as 100% maximum voluntary contraction (MVC). We then used pressure-sensitive film and a clenching strength measuring device to measure occlusal load and occlusal contact area at clenching strengths of 40, 60, 80, and 100% MVC. Finally, we used silicone testing material and an occlusal contact measurement device to measure occlusal contact area at clenching strengths of 20, 40, and 60% MVC.
Results: Occlusal load and occlusal contact area of the bilateral molar region increased at all clenching strengths 3 months after fitting the prosthesis. However, the quotient of bilateral molar occlusal contact area divided by occlusal load (contact area/ load) showed no significant changes after 3 months for any of the clenching strengths. There was also no significant change observed in occlusal load of the prosthesis, occlusal contact area of the prosthesis and contact area/load significantly
Conclusion: Wearing an implant-supported prosthesis for 3 months increased clenching strength, which increased the overall bilateral molar occlusal contact area and occlusal load. Our findings suggest that implant-supported prostheses increase occlusal contact area at high clenching strengths after 3 months of use.
Clinical significance: This study suggested that implantsupported prosthesis which have ideal occlusal contact status need to be checked and occlusal status adjusted regularly for its prediction.