A 30-year retrospective study of single-unit and splinted implant supported crowns and their effects upon adjacent tissues and teeth in a Canadian Dental School Environment

Abstract

Objective: A retrospective study at a Canadian dental school evaluated the survivability of single-unit and splinted implant supported crowns and their effects on adjacent tissues. Methods: Data from patients of all ages was collected from the institution’s computer patient management software (AxiUm) and physical charts. Results: A total of 678 implant supported crowns (586 single-unit and 92 splinted) were placed at the University of Manitoba Dr. Gerald Niznick College of Dentistry between September 10, 1989 to January 1, 2020. Of the implant cases, 249 (36.7%) of them were smokers, 64 (9.44%) were diabetic and 96 (14.2%) were reported to experience bruxism. Within the duration of the study, 17 (2.90%) single-unit crowns and 5 (5.43%) splinted crowns failed and warranted a replacement. Furthermore, 371 single-unit (63.3%) and 46 splinted (50.0%) implant crowns were a complete success as they had no complications with the crown itself or adjacent tissues. Therefore, 215 single-unit (36.7%) and 46 splinted (50.0%) crowns endured some type of complication with the crown or adjacent tissues which may have led to its failure. Overall, 96.8% of cases experienced no failure as of the study end date and a log rank test was performed to determine if there were differences in the survival distribution for the single-unit and splinted implant supported crowns (χ2(2) = 1.285, p = 0.257). Conclusion: The survival distribution of single-unit and splinted implant supported crowns was not statistically significant as they both presented with high success rates and minimal complications. Although some limitations and challenges were present, this study highlights the longevity and complications of implant supported crowns in order to improve their functionality and lifespan as well as to maintain the health of adjacent teeth.