The effect of one-time abutment placement on interproximal bone levels and peri-implant soft tissues: a prospective randomized clinical trial.

Abstract

To compare the effect of placing the definitive abutment at the time of implant placement versus at a later stage, on the soft and hard tissue changes around dental implants. Platform-switched implants were placed in the posterior maxilla or mandible of partial edentulous patients and they were randomized to receive the definitive abutment at the moment of implant placement, or 6-12weeks later. Final prostheses were delivered 2-4weeks later. Radiographic assessment of vertical bone level changes (primary outcome), clinical status of peri-implant tissues, changes in soft tissues margin, papilla filling, patient-related outcomes and adverse events were assessed 6 and 12months after loading. 60 implants were placed in 40 patients, replacing single or multiple absent teeth. One implant was lost 1week after insertion (overall survival rate: 98.3%). A statistically significant greater bone resorption from surgery to 6months post-loading was observed for those implants subjected to abutment change (control group: -1.24±0.79mm; test group: -0.61±0.40mm; P=0.028). Periodontal clinical parameters and patient-related outcomes, however, did not demonstrate significant differences between groups at any time point. A significant increase in papilla height was observed from loading to 12months in all implants (control group: 1.17±1.47mm; test group: 0.98±0.89mm) and a slight but not significant coronal migration of the gingival margin. The connection and disconnection of healing abutments is associated with significantly increased bone loss during the healing period between implant placement and 6months post-loading, when compared to one-time abutment placement.