Effect of Intramobile Mechanism for Osseointegrated Implants on Properties of Mobility， Occlusion and Masticatory Function

Abstract

Recently, prosthodontic treatment for partially and completely edentulous patients changed with the provision of the prosthesis supported by osseointegrated implants. Osseointegration is a stability concept in which achieving and maintaining implants stability during functional loading are prerequisites for successful long-term function. Implant research has focused on the requirements for successful osseointegration and long-term performance of root components. In contrast, the instruments, abutment attachments and techniques designed for prosthodontic treatment have evolved on the basis of individual experience and professional opinion, with minimal evidence of published prospective laboratory or clinical testing. The purpose of this study was to investigata functional mastication using different intramobile mechanisms to fasten the superstructure of implants. IMZ implants functioning in 6 patients and 20 normal subjects were selected. On each IMZ implant the same superstructure for experiment was fastened with IME, IMC or titanium element(Ti). The horizontal mechanical mobility of each implant was measured three times by T-M (Tooth Mobility) tester. Occlusal contacts and area of patients were measured by the Add-picture system, and muscle activity of the masseter, anterior temporal muscles was evaluated by electromyography. The obtained data were compared with data for normal subjects.
The results were as follows:
1. As for using MI scores, the mechanical mobility of the implants was smaller than those of the tooth, and the difference of the viscoelastic properties were even more marked.
2. In case of IMC or Ti within the IMZ implants,there was significant difference between tooth and implants, but there was on statistically significant difference between tooth and IME within the IMZ implants.
3. The occlusal contacts in intercuspal position differed in percent of increase for occlusal contact scores and contact area from tooth with the increase level.
4. The occlusal contacts differed with any elements in the IMZ implants.
5. The percent of increas for occlusal contacts scores in case of IME within the IMZ implants showed approximately the same as those of tooth,but in case of IMC or Ti within the IMZ implants,there was significant difference between tooth and implants.
6. There was difference of MKG and EMG parameter between tooth and implant side during deliberate unilateral gum chewing.
The results suggested that the intramobile mechauism affects mobility, occlusion and masticatory function.