Survival analysis of dental implants and implant-retained prostheses in oral cancer patients up to 20 years

Objectives The purpose of this study was to evaluate the long-term survival rate and potential influencing factors of dental implants and implant-retained prostheses in oral cancer patients who had undergone surgical tumor resection. Material and methods In the present study, 157 patients (95 females and 62 males with a mean age of 53.7 years) with 830 implants were included. All patients were diagnosed with a malignant tumor in the oral cavity and had undergone ablative surgery. In 55 patients (292 implants), the surgical procedure was followed by an additional radiochemotherapy (RCT) before implant placement. Nicotine users who received RCT were excluded from this study. Patients were clinically examined every 6 or 12 months according to a standard procedure. Results Of the 830 examined implants, 450 were placed in the maxilla and 380 in the mandible. A total of 65 implants were lost, 36 in the maxilla and 29 in the mandible; of these, 42 implants (65%) were documented as lost due to the patient's death. The mean observation period was 121 months. The cumulative survival rate was 94.9% at 3 years and 92.5% at 7 years. With an observation period up to 20 years, the cumulative survival rate remained constant after 11 years with 90.8%. Age, gender, and localization (maxilla/mandible) of implants did not show any influence on the survival of the implants. However, radiochemotherapy was determined as a significant factor influencing the survival rate. Conclusions The results of this study demonstrate that the survival rate of implants was significantly lower in oral cancer patients who had been treated by ablative surgery and additional radiochemotherapy than in patients without RCT. Since there is no significant difference in the mortality rate of patients with additional RCT compared to patients who underwent sole ablative surgery, the higher loss ratio is due to a late failure of osseointegration. Clinical relevance Dental implants in oral cancer patients who had been treated by ablative surgery show a high and steady cumulative survival rate after 11 years. Implant survival of patients with additional RCT is significantly lower. Non-smoking-irradiated patients seem to have a better implant survival.