Microradiographic and histological analyses of 17 long standing human dental implants

Objectives: Dental implants are widely used nowadays in single-tooth loss or for anchoring a dental prosthesis. For a long standing the implant must be sufficiently osseointegrated. In anatomical specimens are to find increasingly dental implants which are useful to investigate. Methods: Microradiographic and histological analyses were performed on 17 dental screw-type implants deriving from the mandibulae of five anatomical specimens aged from 69 to 87 years. For three individuals data were available by inquiring the relatives: implantation was 11, 10 and 7 years before death. One of the three cases was a tumor patient. The interforaminal part of the mandibula was resected 7 years before death and replaced by an iliac crest autograft, into which four implants had been inserted some time later. Each of the 17 implants was isolated by cutting the mandible into bone blocks. After embedding, cutting and grinding the sections were x-rayed and stained. Results: With exception of the tumor patient, in all cases an intimate contact between compact and/or cancellous bone and implants was given. No translucent lines between bone and implant were detectable by microradiography. The threads and interspaces of the implants were in contact with mineralized, new compact bone, or spongy trabeculae reached the implants surface rectangulary. Bone resorption phenomena were observed in the crestal area only. Conclusion: The results show that functional loading for even more than ten years is the basis for biomechanical integration of dental implants. Continuous bone remodeling seems to guarantee implant stabilisation independent from age.