Bone Changes and Mobility around Implant Body

Bone Changes and Mobility around Implant Body
26 June 2003
I. TODA, H. IKE, Y. MURATA, N. UEDA, A. TAKEMURA, M. UEMURA, K. SARATANI, Y. KOMASA, T. KAWAZOE, and F. SUWA, Osaka Dental University, Hirakata, Japan
IADR
Objectives: When an implant is inserted as a superstructure, the occlusal load is first conveyed to the implant body and then to the osseous tissue around it. Thus, it may be considered that the osseous tissue around the implant body will show changes during occlusal functioning. We studied the relationship between mobility and bone changes around an implant body caused by occlusal function, employing roentgenography and mobility measurements. Methods: After molar extraction and healing, an implant was inserted into the bilateral mandible of adult Japanese monkeys. A secondary surgery was performed 12 weeks after insertion, and 3 weeks later a single metal crown was applied as a superstructure. It was confirmed that the occlusal contact of the metal crown fitted well with the maxillary teeth. The mobility of the implant was determined at intervals of 1, 4, 8, and 12 weeks after the metal crown application. Some animals were euthanized after every determination, and bone and microvascular cast specimens were prepared by an acrylic resin injection method and observed under a scanning electron microscope. Results: Bone around the implant body proliferated from the existing bone from 1 - 8 weeks after metal crown application to the extent that it surrounded the implant body. Bone proliferation at 8 and 12 weeks after crown application was similar. At 8 weeks, the trabecula supporting the bone began to be arranged and mobility showed a decreasing tendency over time as the bone proliferated. However, the rate of decrease declined in the period from 8 to 12 weeks. Conclusion: The findings showed that bone proliferation changes around the implant body over time were associated with the decline in mobility. Thus, we considered that bone changes around the implant body could be determined by measurements of the mobility.