Surgical, prosthetic, and systemic factors associated with radiographic marginal bone levels in two-implant-supported splinted restorations: a retrospective study

Purpose

This study evaluated the influence of surgical, prosthetic, and systemic factors on marginal bone loss (MBL) in patients restored with two-implant-supported splinted prostheses using radiographic assessment.

Materials And Methods

Patients who received two-implant-supported splinted restorations between 2019 and 2024 were included. Radiographs obtained at prosthesis delivery and at annual follow-up visits for up to five years were analyzed. Surgical variables included implant diameter, length, insertion depth, inter-implant distance, and bone grafting. Prosthetic variables comprised emergence profile, emergence angle, and implant-abutment connection type. Demographic data and systemic conditions were also recorded. Linear mixed-effects models were used to identify factors associated with MBL (P < .05).

Results

A total of 276 implants in 127 patients were analyzed (mean follow-up, 2.2 years). Greater implant insertion depth and external implant-abutment connections were significantly associated with increased MBL, whereas concave emergence profiles were associated with reduced MBL. Implant dimensions, inter-implant distance, bone grafting, systemic conditions, age, and sex were not significantly associated with MBL. The relatively short mean follow-up period (2.2 years) should be considered when interpreting these findings.

Conclusion

Within the limitations of this retrospective radiographic study, implant insertion depth, implant-abutment connection type, and emergence profile were significantly associated with MBL in two-implant-supported splinted restorations. Careful consideration of these factors may contribute to improved peri-implant tissue stability, although longer-term studies are needed to confirm these findings.