ENDOSTEAL IMPLANTS IN THE IRRADIATED LOWER JAW

Since 1990 Endosteal implants have been inserted in the irradiated low er jaw at our clinic, IMZ implants have been used for dental rehabilit ation in 26 patients (21 male, 5 female) suffering from squamous cell carcinomas stage T2-T4136, The implants were either placed in local bo ne and soft tissue (group 1, n=60 implants), or in local bone after ma rginal mandibulectomy and transplanted soft tissue (group 2, n=26 impl ants), 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 am ount of marginal bone loss and the degree of marginal infection betwee n the three groups (P>0.29). Major complications: A mandibular fractur e passing through an empty implant socket 8 months after implant loss (Group 2) was caused by postradiation-osteonecrosis; implant removal a nd bone resection was mandatory, The poor results of the bone graft gr oup may be explained by two patients, in whom simultaneous placement o f implants in nonvascularized bone grafts was carried out, intraoral t issue breakdown led to graft failure and loss of the implants (n=10).