Osseointegrated implants are now an accepted part of the prosthetic treatment of edentulous patients. More recently, osseointegrated implants have been advocated in the treatment of partially dentate patients. The implants can be used in conjunction with natural teeth for the support of rigid prostheses. The natural tooth is supported in bone by a periodontal ligament, whereas the implant may be described as having a more intimate or ankylotic connection with the supporting bone. Different attachment mechanisms may lead to differential rates of destruction in both situations, particularly if teeth and implants are splinted together by a rigid prosthetic appliance. Also noteworthy are the possible differential rates of marginal tissue breakdown as a result of the influence of bacteria. Results of a pilot study in which marginal breakdown was induced around implants and natural teeth in beagle dogs suggest that the process of destruction proceeds more slowly in the case of implants. However, the disease process around implants may be more difficult to arrest due to conjectural problems in treating the surface of the implant using conventional techniques of periodontal treatment. From the limited data available so far, it would appear that osseointegrated implants can be used as predictably in partially dentate as in totally edentulous mouths. More research should be initiated on the potential for tissue-breakdown, and long-term maintenance of the marginal tissues around implants.