Survival of dental implants in native and grafted bone in irradiated head and neck cancer patients: A retrospective analysis.

Aim: To study the long-term survival of dental implants placed in native or grafted bone in irradiated bone in subjects who had received radiation for head and neck cancer. Materials and Methods: A retrospective chart review was conducted for all patients who received dental implants following radiation treatment for head and neck cancer between May 1, 1987 and July 1, 2008. Only patients irradiated with a radiation dose of 50 Gy or greater and those who received dental implants in the irradiated field after head and neck radiation were included in the study. The associations between implant survival and patient/implant characteristics were estimated by fitting univariate marginal Cox proportional hazards models. Results: A total of 48 patients who had prior head and neck radiation had 271 dental implants placed during May 1987-July 2008. There was no statistically significant difference between implant failure in native and grafted bone (P=0.76). Survival of implants in grafted bone was 82.3% and 98.1% in maxilla and mandible, respectively, after 3 years. Survival of implants in native bone in maxilla and mandible was 79.8% and 100%, respectively, after 3 years. For implants placed in the native bone, there was a higher likelihood of failure in the maxilla compared to the mandible and there was also a tendency for implants placed in the posterior region to fail compared to those placed in the anterior region. Conclusion: There was no significant difference in survival when implants were placed in native or grafted bone in irradiated head and neck cancer patients. For implants placed in native bone, survival was significantly influenced by the location of the implant (maxilla or mandible, anterior or posterior).

Prevalence And Distribution of Vertical Osseous Defects In Patients Being Treated For Chronic Periodontitis.

Background: The aim of the study was to determine the prevalence and distribution of vertical osseous defects in patients who underwent open flap debridement. Methods: A total of 83 subjects were examined for prevalence of vertical defects using direct observation during periodontal surgery. All patients required periodontal surgery in one or more segments. The diagnosis of periodontitis was made after clinical and radiographic examination. Periodontal surgery was performed on each patient and full thickness mucoperiosteal flaps were elevated to gain access to root and osseous structures. The vertical osseous defects were explored surgically using mouth mirror, explorer and a periodontal probe. Results: A total of 141 vertical osseous defects were detected in the 677 teeth assessed during surgical exposure. Of these 81 vertical defects were found in the maxilla and 60 vertical defects were found in the mandible. Craters accounted for almost 44% of the total defects. The posterior maxilla had the highest percentage of teeth with vertical defects (26.23%) while the mandibular anterior segment had the lowest percentage of vertical defects. Conclusion: The posterior maxilla had the highest percentage of vertical osseous defects which can be explained by the fact that greater thickness of supporting bone allows formation of a greater number of infrabony defects. Craters were found to be the most common defect.