The Effect of Two-Piece Abutment Concept and Abutment Reconnection/Disconnection on Marginal Bone Level Changes: A...

The objective of this study was to conduct a comparative evaluation of the clinical and radiographic findings of definitive two-piece abutments placed at secondary surgery following submerged healing and definitive abutments used in standard prosthetic treatments.

The study was designed as a prospective, split-mouth, randomised, parallel-design, blinded clinical trial. The study comprised two groups: a test group and a control group. The test group received a two-piece abutment, while the control group received a standardized healing abutment. The study analyzed a total of 10 patients and 20 implants. Clinical and radiographic measurements were obtained at baseline (T0), 6 months (T1), 12 months (T2) and 36 months follow-up (T3). Radiographic measurements were calculated on standardized periapical radiographs, with the aim of determining marginal bone level changes (ΔMBL) at different time points, emergence angles, and emergence profiles in mesially and distally.

A significant difference was found between the groups in mesial, distal, and mean ΔMBL at T0-T1 and distal and mean ΔMBL at T0-T3 values. (p<0.05) Emergence angle values were found to be below 30 degrees both mesially and distally in both groups. (p>0.05) A statistically significant correlation was found between healing/definitive abutment disconnection/reconnection and distal ΔMBL T0-T3. (p<0.05) Conclusion: Within the limitations of the study, although the sample size was limited, with the study design and minimizing confounding factors, it was concluded that two-piece definitive abutment application may have significant effects in terms of reducing ΔMBL changes in both the short and long term. However, further studies with a larger sample size are needed. The study was prospectively registered on the international Clinicaltrials.com registry (NCT05592821).