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. However, the induced MNGC-related tissue reaction came with a significantly higher vascularization within the implantation bed. Regarding the new bone formation within the implantation bed, it must be mentioned that the results of new bone formation after an integration period of 6 months did not differ between the synthetic and the xenogeneic bone substitute material [16].