抄録
Intra-Mobile Zylinder(IMZ)implant, a kind of osseointegrated implant, is equipped with Intramobile Element(IME)between the superstructure and the implant. It was reported that IME gave a shock-absorption effect, being similar to that of periodontal tissues. Though IMZ implant is made of pure titanium, IME is consisted of synthesized organic materials, which may be deteriorated or permanently deformed during long-term usage. To confirm this possibility, we observed by SEM the surface configuration of IME which had been used clinically for 1 or 2 years and collected from 3 edentulous patients, and we also analysed extrinsically deposited materials on the surface of IME by means of EDAX. As a result, the following findings were obtained:
1)There were no signs of complete fracture or breakage into the deep part of IME among the IME we collected.2)On the outer-surface of IME, deposited materials containing Ca and P were found,which might be derived from tarter oris or calculus.3)The internal thread of IME was destroyed, while the outer thread of IME was intact.4)It was indicated that a tight fastening between the internal thread of IME and the prosthesis-fastening Screw was loosen because the surface of the internal thread was scratched to be worn off by the relative motion of prosthesis-fastening Screw. 5)Therefore, it is clear that IMZ implant allowed the prosthesis to mobile not only by the physical property of IME but also by loosening of the fastening Screw. These findings suggest that A)IME should be checked periodically and changed at least once a year for maintaining the unique function of IME and B)The present design of IME should be improve to tightly close an avenue from outer environment.
