Outcome of implant therapy in relation to experienced loss of periodontal bone support -: A retrospective 5-year study

Purpose: The aim of this retrospective study was to analyse bone level alterations over a 5-year period at implants in the maxillary posterior segments in patients with varying experience of periodontal bone loss in the natural dentition before implant placement. Material and methods: 97 partially dentate patients with a total of 346 Branemark(R) oral implants in the maxillary posterior segments were included. By assessing the degree of radiographic marginal bone loss in the remaining natural dentition at time of the implant therapy, an age-related bone loss score (ArB-score) was calculated for description of the patient's experience of periodontal destruction. The two end quartiles; of the distribution of the subjects with regard to the ArB-score were defined as Non-Perio subjects and Perio subjects, respectively. The primary outcome variables were implant losses (implant failures) and radiographic peri-implant bone loss over the 5-year observation period. Results: A total of 18 implants were lost during the 5 years, resulting in an overall failure rate of 5.2%. The corresponding failure rate was 3.3% for the Non-Perio and 8.0% for the Perio patients. The peri-implant bone loss from the time of abutment connection to 5 years averaged 1.8 mm (SD 0.7). Of the patients, 34% showed a mean bone loss of > 2 mm and 39% of all implants had experienced a bone loss of 2 mm at the 5-year examination. The Non-Perio and Perio patients showed a mean bone loss of 1.7 mm (0.8) and 2.2 mm (0.8), respectively. Multiple regression analysis revealed a statistically significant relationship between the ArB-score and the peri-implant bone level change from abutment connection to 5 years (P < 0.05). In all, 64% of Perio patients had a mean peri-implant bone loss of > 2 mm from the time of abutment connection, compared to 24% for the Non-Perio patients (P < 0.01). The percentage of implants showing 2 mm of bone loss between abutment connection and 5 years was 62% and 44% in the Perio and Non-Perio groups, respectively (P = 0.055). Conclusion: The results indicate that longitudinal bone loss around implants is correlated to previous experience of loss of periodontal bone support and that periodontitis susceptible subjects may show an increased implant failure rate.