Comparison of two different abutment designs on marginal bone loss and soft tissue development

To assess the response of soft tissues around two different abutment designs in healed sites in the esthetic zone.

Twenty-six subjects received two endosseous implants in healed, bilateral implant sites in the esthetic zone in the maxilla or the mandible. After 17 to 19 weeks and left/right randomization, the implants were restored with either a conventional (control) or curved (experimental) titanium abutment and a provisional crown. Eight weeks after abutment placement, definitive crowns were cemented (T0). Soft tissue development was assessed based on peri-implant bone loss, Pink Esthetic Score (PES), and probing depths immediately after placement of the definitive crown and after 1 year (T12) and compared between sites. Possible confounding variables (abutment angle, plaque presence, gingival bleeding, width of attached mucosa) were also documented at T0 and T12.

The mean peri-implant marginal bone loss from T0 to T12 was 0.00 ± 0.37 mm in the experimental group and 0.12 ± 0.27 mm in the control group. Differences were not statistically significant (P = .25). At T12, the curved abutment scored a mean PES of 10 ± 2.3 and the straight abutment scored 9.7 ± 2.3. The difference was not significant (P = .46)). Probing depths were also not significantly different between the two groups (P = .85). Correlation and regression analysis showed no hints of predictive behavior for the possible confounding variables.

A titanium abutment with a circumferential curved design is of no additional benefit to soft tissue development and preservation of marginal bone compared to a conventional straight abutment design for the restoration of single-tooth implants in the esthetic zone.