Marginal Bone Changes at Bone-Level Implants With Narrow or Standard Diameter Abutments: 1-Year Results of a Randomised Controlled Trial

Abstract

Aim

To evaluate changes in the peri-implant marginal bone level at implants restored with narrow or standard-diameter abutments after 12 months.

Material & Methods

Twenty-eight partially edentulous patients were randomly allocated to two groups. The test group consisted of 14 patients restored with a 2.9 mm diameter abutment (21 implants), while the control group included 14 patients restored with a 4.1 mm diameter abutment (17 implants). The primary outcome variable was the radiographic change in the peri-implant marginal bone level at 12 months, measured as the distance from the implant shoulder to the first bone-to-implant contact (fBIC). Secondary outcome variables included clinical peri-implant parameters, the papilla index, biological and mechanical complications, patient-reported outcomes (PROs) and professional aesthetic assessment.

Results

A per-protocol analysis was conducted on the 22 patients who completed all scheduled follow-up visits. At the patient level, the change in mean radiographic bone level from definitive prosthesis placement to 12 months showed a reduction in the distance from the implant shoulder to the fBIC of 0.16 ± 0.31 mm in the test group and 0.21 ± 0.34 mm in the control group, with no statistically significant differences between the groups. No statistically significant differences were observed between the two groups for any of the secondary outcomes.

Conclusions

Considering the limitations of this study, no significant differences in peri-implant marginal bone levels were found between bone-level implants restored with narrow and standard diameter abutments after 12-month follow-up. Additionally, no differences were observed in clinical variables, patient-reported outcomes, or complications.