In the present retrospective study, C-Tech bone level implants placed simultaneously with a GBR procedure around the implant shoulder were investigated clinically and radiologically after at least 3 years of loading to assess peri-implant tissue conditions and document peri-implant tissue stability.

A total of 47 implants were placed in the upper (23 implants) and lower jaw (24 implants) of 20 patients. In all implants, lateral augmentation in a GBR process was performed simultaneously with implant placement due to a reduced horizontal or vertical height of the alveolar crest. The bone substitute materials applied to the horizontal and vertical GBR procedures were of synthetic origin. The clinical and radiological follow-up investigation revealed a survival rate of 100% and only low median rates for probing depths (2.7 mm) and BOP (30%). The mean PES was 10.1 from a maximum value of 14. No osseous peri-implant defects were obvious, and the mean bone loss calculated digitally was 0.55 mm, ranging from 0 to 3 mm.

The tissue reactions to bone substitute materials of different origins have been widely investigated by our research group [16,17,18]. It could be shown that the origin, the physico-chemical structure, and the processing techniques have an impact on the cellular tissue reaction within the augmentation bed. In a clinical study, the tissue reaction to a synthetic, HA-based and xenogeneic, bovine-based bone substitute material was compared histologically and histomorphometrically in a two-stage sinus augmentation procedure. It was shown that the synthetic bone substitute material induced a significantly higher expression of multinucleated giant cells (MNGCs) within the implantation bed compared to the xenogeneic bone substitute material.