Clinical analysis of implant losses in oral tumor and defect patients

In the period between 1990 and 1996, 279 endosteal dental Bone-Lock implant s were placed in 79 patients. Of them 63 have been treated with ablative tu mor and reconstructive surgery in the oral cavity, the rest presented with maxillo-mandibular defects of different origin. The circumstances of implan t loss were noted down for descriptive analysis concerning age, sex, topogr aphy, implant dimensions, loading, time in place and type of superstructure . Failure analysis was done concerning the implants and the patients. Five causes for implant loss could be detected: lacking primary osseointegration , acute inflammation, bone loss, biomechanical overloading and tumor recurr ence. No predictive factors for implant loss and no age influence on implan t loss could be detected, no specific local implant site and no specific su perstructure had an identifiable higher risk. Survival rate of all placed i mplants in oral tumor and defect patients was 83.5% after 6 years observati on. Male tumor patients were found to have a higher risk to lose implants t han females. Free iliac bone grafts impaired osseointegration of implants. The mandible offered a better prognosis for the implants than the maxilla. Shorter and thinner implants had a higher risk of being lost. A quarter of all patients (26.3%) had to face implant loss. Clustering of implant loss i n several patients was caused by free iliac bone grafting and by prosthetic faults. Chemotherapy had no negative influence on implant survival. Most i mplants were lost early (76%) before fabrication of the prosthesis. After r estoration there was a nearly 100% probability of function. It is concluded that implant treatment can be equally effective for tumor and defect patie nts as it is known for healthy subjects.