Page 168 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability

CHAPTER 7
integrated platform shift with smooth implant bevel. For the purpose of this study the experimental implants differed only in one factor as clarified in Figure 1. The commercially available implant (DCC, Southern Implants) has an internal connection and microthreaded neck (I-MT), the three experimental implants (Southern Implants) existed of an implant with an internal connection and without microthreaded neck (I-NMT), an implant with an external connection and with microthreaded neck (E-MT), and an implant with an external connection and without microthreaded neck (E-NMT). All implants used for this study had a diameter of 4 mm and a length of9or11mm.
Each patient received all four study implants in the edentulous maxillainaone-stage surgical procedure with open flap. The preferred implant locations were the canine and first molar region. However, in case of insufficient bone at the molar region the second premolar site was chosen. Implant types were allocated by means of a computerized randomization scheme. Directly after implant placement, a definitive titanium implant abutment with a height of 4 mm (Compact Conical Abutments, Southern Implants) was installed, using a 20 Ncm torque. These abutments were temporary covered with healing caps.
After implant surgery, the conventional denture was adjusted with a soft reliner (Coe Soft, GC Europe, Leuven, Belgium) in direct contact with the healing caps. The direct contact of the prosthesis with the healing caps could be considered as an immediate functional loading with a provisional removable denture. The occlusion and articulation as well as the fit of the denture were checked every 2–3 weeks to avoid overload and the soft reliner was renewed whenever required. To control the clinical osseointegration the titanium implant abutments were torqued at 30 Ncm after a minimal healing period of 4 months. If good clinical osseointegration was achieved, impression was taken on abutment level, and a titanium bar was designed and milled using CAD-CAM technology. The maximum allowed extension of the bar was 8 mm. All final prosthesis had a metal frame and a partial coverage of the palate.
The ethical committee of the Ghent University Hospital approved the study protocol under the Belgium registration number B670201524372. All patients were thoroughly informed about the treatment, signed written informed consent, and were treated between September 2015 and September 2017 at the Ghent
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