A Prospective, Observational Clinical Study Evaluating Marginal Bone Levels and Volumetric Changes of Subcrestally Placed Platform Switch Dental Implants – Preliminary 1 Year Follow Up Data

Purpose This prospective cohort study evaluated marginal bone levels (MBL) stability and peri-implant tissue volumetric changes around platform-switched implants over 12 months post-loading. The null hypothesis was that crestal bone levels would be stable over one year period and soft-tissue parameters would have a positive correlation to 3D volumetric changes with high patient satisfaction. Methods/Materials This study is a prospective observational study designed to assess implant survival rates and crestal bone changes over one year. A total of 35 patients, each requiring at least one implant to replace a missing posterior tooth, met the inclusion criteria and participated in the study. Medical and dental history, Cone Beam Computed Tomography (CBCT) analysis, periapical radiographs, and digital impressions were collected at baseline. Clinical parameters were also collected including gingival index (GI) and plaque index (PI). Standardized radiographs were further taken at implant placement, prosthetic phase, and at one-year follow-up for the evaluation of crestal bone changes. Digital impressions taken at baseline, prosthetic phase and at one-year follow-up were superimposed in specific metrology software for volumetric analysis. Implant survival rate was assessed via absence of implant mobility, and pain, with implant being in function. Patient-reported outcomes were measured through the administration of surveys at the one-year follow-up. Crestal bone changes were evaluated through a paired t-test. Logistic regression was utilized to evaluate the local and systemic factors that influenced crestal bone changes. Associations between complications and patient-reported outcomes were inferred. Results A total of 34 patients were recruited and 25 were included in the analysis after 2 patients failed and 1 voluntarily withdrew. The results demonstrated clinically significant MBL changes from T1-T2 and T1-T3, but not from T2-T3, with an average loss of 0.60–0.65 mm, stabilizing at 0.08 mm below the implant platform. Notably, baseline bone levels were the strongest predictor of MBL changes (p< 0.002). Volumetric analysis using 3D optical scanning revealed significant dimensional changes in peri-implant soft tissues, primarily occurring coronally on the buccal aspect (p=0.0008) and more apically on the lingual (p=0.0019). Implant survival was 94.1% with 100% of the implants for the cohort followed for 1 year maintaining peri-implant health. There were 0 implants that were diagnosed with periimplantitis over the course of the study. Patient satisfaction was high with 88.9% for ‘excellent’, 11.1% for ‘good’, and 0% for ‘poor’. Conclusion Rehabilitation of single posterior edentulous sites using subcrestally placed platform switched implants yield high implant survival, favorable crestal bone levels and volumetric peri-implant tissue stability over a period of 1-year with a high-rate of peri-implant health observed while maintaining excellent patient satisfaction.