Changes in Peri-Implant Bone Level and Effect of Potential Influential Factors on Dental Implants in Irradiated and Nonirradiated Patients Following Multimodal Therapy Due to Head and Neck Cancer: A Retrospective Study.

PURPOSE: The aim of the present study was to evaluate changes in the marginal bone level of dental implants in irradiated and nonirradiated patients and to identify possible influential factors. MATERIALS AND METHODS: Thirty-six patients with 194 implants were involved in the study (7 women and 29 men). The mean age of the patients was 65.8 years (39 to 90 yr). In all patients, a squamous cell carcinoma in the floor of the mouth involving the mandible or tongue was surgically removed. In 17 patients, adjuvant radiochemotherapy was completed a minimum of 6 months before implant placement. Mean crestal bone changes using standardized orthopantomographs were evaluated. The Spearman rank-order correlation coefficient and Mann-Whitney U test were used to determine correlations between bone crestal changes and age, gender, radiation therapy (yes vs no), augmentation (yes vs no), and type of superstructure. RESULTS: In total, 194 implants were placed (73 in the maxilla and 121 in the mandible). Mean amounts of peri-implant bone loss were 1 mm mesially and 0.9 mm distally after 1 year and 1.4 mm mesially and 1.3 mm distally after 3 years. During the observation period, 4 implants were lost. The overall success rate was 98.4% (maxilla, 100%; mandible, 96.7%). There was no relevant difference in changes in bone level according to age, gender, prosthetic superstructure, or augmentation procedure (yes vs no). Radiation therapy was found to have an effect on crestal bone loss. CONCLUSION: The present study showed a high success rate of dental implants after 3 years. Peri-implant crestal bone loss was comparable to that in patients without tumor. The mean amount of crestal bone change in irradiated patients was twice as high as that in nonirradiated patients.