[Early detection of threatened implant loss in tumor patients].

After resection of an oropharyngeal tumor, 157 dental implants were placed in 17 irradiated (44 Gy on average) and 20 non-irradiated patients. Within a control period of 37 months, 15 implants had failed. The reason for implant failure was analyzed, whereby indicative parameters were revealed. Eleven implants in four irradiated and one non-irradiated oral cancer patients showed no primary osseointegration during the healing period because of mandible fracture, overloading or for unknown reasons. Four implants in one irradiated and three non-irradiated oral-cancer patients were lost subsequently on average 39 months after second-stage surgery due to biomechanical overloading or bacterial infection. No osteoradionecrosis development due to implant failure was observed in irradiated patients. In all cases, peri-implant pocket depth, implant stability and peri-implant bone resorption increased before definitive implant failure. Therefore, these findings seem to be useful as indicative parameters in the prediction of implant failure.