Objective: 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.
Material and methods: 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 6-12 weeks later. Final prostheses were delivered 2-4 weeks 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 12 months after loading.
Results: 60 implants were placed in 40 patients, replacing single or multiple absent teeth. One implant was lost 1 week after insertion (overall survival rate: 98.3%). A statistically significant greater bone resorption from surgery to 6 months post-loading was observed for those implants subjected to abutment change (control group: -1.24 ± 0.79 mm; test group: -0.61 ± 0.40 mm; 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 12 months in all implants (control group: 1.17 ± 1.47 mm; test group: 0.98 ± 0.89 mm) and a slight but not significant coronal migration of the gingival margin.
Conclusions: The connection and disconnection of healing abutments is associated with significantly increased bone loss during the healing period between implant placement and 6 months post-loading, when compared to one-time abutment placement.
Keywords: alveolar bone loss; dental implant-abutment design; dental implants; patient outcome assessment; platform switching; randomized controlled trial.
© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.