Retrospective Evaluation of Factors Related to the Outcomes of Regenerative Therapy for Implants Affected by Peri-implantitis

The aim of this retrospective study was to examine the histories of 100 patients with 170 implants that were consecutively treated and reported in a previous study to identify which patient and implant factors might have affected the outcomes of therapy. Patient factors included history of periodontitis, hypertension, cardiac problems, rheumatoid arthritis, smoking, and penicillin allergy. Implant factors included whether the prosthesis was cemented or screw retained and initial bone loss (≤ 50% or > 50% of implant length). Frequency of maintenance visits (≤ 3 months or > 3 months) were recorded, as was patient age (≤ 60 years or > 60 years). On the patient level, only postoperative maintenance (≤ 3 months) showed a statistically significant effect on radiographic bone gain (RBG) compared to patients with > 3 months maintenance frequency. Nondiabetic patients showed a trend toward soft tissue gain. On an implant level, screw-retained prostheses demonstrated a statistically significant RBG compared to those with cement-retained prostheses. Significant favorable differences were seen in all outcomes when evaluating presurgical bone level loss (> 50% of the implant length). Further studies with larger groups of patients are necessary to substantiate the findings in this report.