Endosteal implants in the irradiated lower jaw.

Since 1990 Endosteal implants have been inserted in the irradiated lower jaw at our clinic. IMZ implants have been used for dental rehabilitation in 26 patients (21 male, 5 female) suffering from squamous cell carcinomas stage T2-T4 136. The implants were either placed in local bone and soft tissue (group 1, n = 60 implants), or in local bone after marginal mandibulectomy and transplanted soft tissue (group 2, n = 26 implants), or in transplanted bone and soft tissue (group 3, n = 52 implants). Life-table analysis according to Kaplan-Meier demonstrated a 3-year implant survival rate of 87.8% in Group 1, 69.1% in Group 2 and 58.3% in Group 3. There was no statistical significant difference in the amount of marginal bone loss and the degree of marginal infection between the three groups (P > 0.29). Major complications: A mandibular fracture passing through an empty implant socket 8 months after implant loss (Group 2) was caused by postradiation-osteonecrosis; implant removal and bone resection was mandatory. The poor results of the bone graft group may be explained by two patients, in whom simultaneous placement of implants in nonvascularized bone grafts was carried out, intraoral tissue breakdown led to graft failure and loss of the implants (n = 10).