Long-Term Survival and Marginal Bone Loss of Nanostructured Calcium-Incorporated Titanium Dental Implants: A Retrospective Observational Study

Abstract

Nanostructured calcium-incorporated titanium dental implants have demonstrated favorable biological activity in preclinical studies; however, supporting clinical evidence remains limited. This retrospective cross-sectional study evaluated the survival and marginal bone loss (MBL) of calcium-incorporated implants placed in routine clinical practice at a university dental hospital. Consecutive implants were included when patients were ≥18 years old, had radiographic data, and completed at least 12 months of follow-up after final prosthesis delivery or experienced implant failure before that time. All implants were internal-connection fixtures with nanostructured calcium-incorporated surfaces, and guided bone regeneration or sinus augmentation was performed when clinically indicated. The primary outcome was cumulative survival rate, estimated using Kaplan–Meier analysis. MBL progression according to functional duration was assessed using linear regression and natural cubic spline modeling. A total of 753 implants were followed for 24–124 months. The cumulative survival rate was 99.6%, with three failures attributed to osseointegration failure, fixture fracture, and peri-implantitis. MBL increased minimally over time, with a linear slope of 0.016 mm/year. Spline analysis indicated a stable, non-accelerating pattern of bone remodeling. Within the limitations of the retrospective design, these implants showed excellent clinical survival and limited long-term MBL progression.