April 2012

Document Type


Degree Name



Oregon Health & Science University


Background: The adoption into mainstream dental therapy of endosseous dental implants manufactured from medical grade titanium has revolutionized the treatment of edentulous sites while demonstrating excellent success and survival percentages. Few studies have evaluated dental implant survival or success within a university residency program. There are even fewer studies that have analyzed implant outcomes by radiographic survey. The primary objectives of this study were to evaluate survival and success of dental implants placed by periodontal residents at Oregon Health & Science University (OHSU) between the years 2002 and 2009 and to assess residual bone height as assessed radiographically, around these implants. A novel radiographic parameter described as dental implant radiographic residual bone height (DIRRBH) is utilized as a measurement of dental implant success. Measurement of dental implant radiographic crestal bone loss (DIRCBL)is also assessed in this study. Secondary aims of this study included determining if various demographic and patient health parameters or if the residency year of the surgeon placing the implant fixture(s) may affect DIRRBH or dental implant survival. Methods: A retrospective clinical chart review was conducted of patients of record at OHSU School of Dentistry who had one or more implants placed by periodontal residents from 2002-2009. Subjects were contacted and invited to participate in a recall examination. During the recall examination clinical assessment of the restored dental implants, a single digital periapical radiograph was taken of each dental implant. Patient demographic, health, and dental implant data were recorded from the chart review and verified during the clinical appointment. An anonymous survey was conducted of all participants in order to evaluate patient satisfaction with the dental implant experience and the final result. Radiographs were then analyzed by two calibrated and independent evaluators. Statistical data analysis was performed using the cox proportional hazard regression model and Kruskal Wallis test. Results were considered significant where the P < 0.05. Results: The case series included 79 patients with 167 dental implants that had been placed. The post-implant placement mean follow-up period was 5.11 years with a range of two to nine years. The study population consisted of 56% female and 44% male subjects. Subject age ranged from 17 years to 85 years, with a mean age of 60.3 years. Implant lengths ranged from 6 to 16 millimeters, with a median length of 11.5 millimeters. Dental implant radiographic residual bone height (DIRRBH) as dental implant fixture length was 90.7%. Females retained a mean of 90% and males 91%; healthy patients retained 91% while diabetics retained 88% of the DIRRBH per dental implant fixture length. DIRRBH per dental implant fixture length was 91% for never smokers. Current and historical smokers retained 89.4 and 89.6%, respectively. Cumulative average radiographic crestal bone loss on the dental implant fixture was 1.03 millimeters (s = 0.882; range 0 - 5.5). Cumulative survival rate over the nine year period was 96.8%. Conclusion: This study reports that endosseous dental implants placed from 2002-2009 achieve survival rates achieved are consistent with accepted published results for dental implant survival. Age, gender, diabetes, smoking, osteoporosis, osteopenia do not significantly affect the combined DIRRBH or overall dental implant survival. There was slightly less non-significant DIRRBH for dental implants placed in diabetics and smokers. Finally, the level of experience of the periodontal resident did not affect dental implant survival in this study.




School of Dentistry



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