Evaluation of survival, success and complication rates of implant-supported single cron and fixed dental prosthesis: Retrospective follow-up up to 5 years

Purpose: The aim of this study is to retrospectively evaluate the survival and success rates of both implants and implant-supported fixed prostheses and their clinical mechanical and biological complications according to restoration type, material type, and retention type. Materials and Methods: The study includes 138 patients (73 females, 65 males) who underwent prosthetic treatment, including 437 implants, 110 single crown restorations (SC), and 116 fixed dental prosthesis (FDP) performed at the Department of Prosthetic Dentistry, NEU DHF. Survival and success rates were determined using implant survival criteria and the Modified USPHS Criteria, which evaluate mechanical and biological complications, including ceramic veneer fracture, marginal fit, contour, mesial contact, color matching, surface discoloration, and patient satisfaction, as well as substructure fracture, screw fracture, implant loss, screw loosening, loss of screw hole sealing, and disintegration, among others. Biological complications were evaluated using the Silness-Löe plaque and gingival indices and clinical findings such as bleeding on probing, erythema, edema, and radiographic images. IBM SPSS Statistics (Version 26.0. Armonk, NY: IBM Corp.) was used for statistical analyses. The chi-square test was used to compare categorical variables. Kaplan- Meier survival analysis was applied to evaluate prosthesis success and survival. The statistical significance level for the study was set at p<0.05. Results: The survival rate of implants in the SC and FDP groups was 99.1% after 5 years. The prosthetic survival rate of SC restorations was found to be 96.36%, while that of FDP restorations was 90.52% (p>0.05). The prosthetic success rate of SC restorations was 50.91%, while that of FDP restorations was 60.34% (p>0.05). Ceramic veneer fracture (SC: 10%, FDP: 20.7%, p<0.05) was the most common mechanical complication, especially in zirconia-supported and screw-retained restorations. Desintegration (SC: 7.3%, FDP: 9.5%, p>0.05), screw loosening (SC: 7.3%, FDP: 8.6%, p>0.05), loss of screw hole sealing (SC: 1.8%, FDP: 0.9%, p>0.05), implant loss (SC: 0.9%, FDP: 0.9%, p>0.05), and screw fracture (FDP: 0.9%) followed this complication. No substructure or abutment fractures were observed. Mesial contact loss was observed in 55.5% of SC restorations and 67.2% of FDP restorations. The most common minor biological complication was soft tissue inflammation (54.2%), followed by perimucositis (32.6%). The most common major biological complication was peri-implantitis (19.2%). Conclusions: The survival rate of both single crown and fixed bridge restorations, as well as the implants supporting them, is high. However, it should be considered that approximately one in two restorations may have a complication that can be defined as a failure within 5 years. Ceramic veneer fracture should be paid attention to, especially in zirconia-supported screw-retained restorations. In the event of any mechanical complication, appropriate treatment should be performed. Proper oral hygiene and regular check-ups are important to prevent biological complications. Keywords: Dental implant survival, Prosthetic success, Mechanical complications, Biological complications, Retrospective study.