Survival of Dental Implants Replacing Previously Failed Implants: A Retrospective Study in a University Setting

Purpose: The rate of dental implant failures ranges from 3% to 8%, with that number increasing as the number of implants placed increases. When an implant fails, the survival rate drops significantly when a second or third attempt is performed. The aim of this study was to evaluate the survival rate of an implant placed in a previously failed implant site and to explore the risk factors that might affect the outcome of the second procedure. Materials and Methods: A retrospective chart review was conducted for patients receiving dental implants at the University of Texas, School of Dentistry from 1985 to 2017. Exclusion criteria included patients with genetic diseases, radiation and chemotherapy, or an age less than 18 years. Data on age, sex, race, tobacco use, diabetes, cardiovascular, osteoporosis, implant brand, anatomical location of the implant, implant length and width, respective information on the replacement implant, and professional maintenance were collected for analysis. Results: A total of 1,234 patients with 2,742 implants were included. A chart review found that of the 247 failed implants, replacement of implants was performed in 85 patients with 99 implants. More than half of the initial implants failed within the first year of placement. Based on the 12-month performance of each brand, the initially failed implants were categorized as high, medium, or low survival rates. Based on this categorization, the replacement implants that belonged to the medium survival rate category showed higher survival rates than the high survival group of the initially failed implants. Conclusion: The cumulative survival rates of the replacement implants were 91% at 1 year, 88% at 5 years, and 83% at 10 years. Implant failures were more common prior to functional loading. Keywords: dental implant, retrospective study, survival rate