Postloading behavior of regenerated tissues in GBR-treated implant sites

The objective of this study was to assess, using reentry procedures, the ca pacity of regenerated tissues in implant-associated defects to respond to o cclusal loading. Two groups of patients treated with membrane-augmented oss eointegrated implants were included in the study. In group A (7 patients), a total of 9 implant-associated defects, including 6 dehiscences and 3 imme diate extraction sites, were prospectively followed up 6 months following p rosthesis connection. in group B (3 patients), 4 dehiscence defects were re trospectively evaluated 5 years after prosthetic loading. All defects in bo th groups had an uneventful healing period beyond the 6 months following im plant insertion and showed complete fill with bone-like hard tissues at abu tment connection surgery. A second surgical reentry was carried out to eval uate the quantitative changes in the regenerated tissues at the membrane-tr eated sites, if was carried out 6 months following prosthesis connection in group A, and 5 years postloading in group B. At the second reentry procedu re, the mean percentage of defect fill at the dehiscence sites was 82% +/- 12.8% in group A and 83% +/- 7.3% in group B. In the 3 immediate extraction sites in group A, the most apical bone-implant contact around the implant was consistently located at about 7 mm, relative to the coronal aspect of t he implant shoulder as evidenced both radiographically and during the secon d reentry. The trends noted in this investigation suggest that tissues rege nerated in successfully treated implant-associated defects can be maintaine d in the short-term and long-term periods following prosthetic loading.