Impact of abutment microstructure and insertion depth on crestal bone changes at nonsubmerged titanium implants with platform switch.

OBJECTIVES: To assess the impact of microgrooved abutments and the insertion depth on crestal bone changes at titanium implants with platform switch. MATERIALS AND METHODS: A total of n = 3 titanium implants (conical abutment connection) were inserted in each hemimandible of n = 6 foxhounds with the implant shoulder (IS) located at either epicrestal, supracrestal (+1 mm), or subcrestal (-1 mm) positions and randomly (split-mouth design) connected with machined or partially microgrooved healing abutments. At 20 weeks, tissue biopsies were processed for histological (primary outcome: net bone loss - NET) analyses. RESULTS: Subcrestal positioning of IS tended to be associated with higher mean NET values (mm) at both machined (subcrestal [-0.72 +/- 0.32] > epicrestal [-0.34 +/- 0.21] > supracrestal [+0.20 +/- 0.64]) and microgrooved (subcrestal [-0.48 +/- 0.25] > epicrestal [-0.13 +/- 0.54] > supracrestal [+0.33 +/- 0.58]) abutments. However, these differences failed to reach statistical significance. CONCLUSIONS: The insertion depth may have a direct influence on crestal bone-level changes at both types of abutments investigated.