Inflammation Associated with Implants is Independent of Surface Types

Different implant surfaces may influence the amount of plaque accumulation which may subsequently affect the peri-implant microflora and the inflammatory lesions around implants. Objectives: The aim of this study was to determine the nature of inflammation associated with different implant abutment surfaces in dogs using histology, immunohistochemistry and microbiology. Methods: Four single-stage experimental implants, consisting 3 tests and 1 control abutment surface were placed on each side of the jaw in random positions in 8 dogs. Tooth cleaning was carried out twice weekly. Plaque samples and gingival biopsies were obtained at 6 months. The 3 test abutment surfaces were an acid etched surface, a machined surface with a circumferential groove and a TiUnite surface. The control was a standard machined surface. 6µm serial cryostat sections were cut from each specimen and processed. The areas of inflammatory infiltrates and the nature of the infiltrating cells were determined. Real time PCR was used to identify Aa, Tf, Fn, Pg. Results: Inflammatory infiltrates were commonly found at the subepithelial areas, and perivascularly. The infiltrating cell were predominantly T cells. CD4:CD8 ratio was approximately 2:1. No statistically significant differences in size or nature of cell types of inflammatory infiltrates were found among the 4 surface types. However, the machined surface with a circumferential groove showed the largest area of inflammatory infiltrate. Aa was not detected while all implants types showed similar distribution in numbers of Tf, Fn, and Pg. Conclusions: These results suggest that the development of inflammation associated with implants is independent of surface types and is similar to the gingivitis lesion of teeth. Implant surface types do not seem to influence the peri-implant microflora. However, the results suggest that a circumferential groove may increase plaque retention leading to increased inflammation. This study was supported by Nobel Biocare.