Early peri-implant tissue reactions on different titanium surface topographies.

The purpose of the present study was to investigate the early peri-implant soft tissue healing on different titanium surface topographies. Titanium implants with smooth or rough surfaces were placed in the extraction site at 1 month after the maxillary first molar extractions of 15 male Sprague-Dawley rats. At 4 and 7 days after implant surgery, the peri-implant oral mucosa was randomly harvested and analyzed for collagen fiber orientation, and expression of extracellular matrix genes. Descriptive and paired t-tests were performed where appropriate (α = 0.05). The laser scanning microscopic analysis of the Sirius red stained peri-implant connective tissue revealed a parallel and uniform collagen fiber orientation along the smooth implant at both 4 and 7 days. In contrast, the collagen fibers of the comparative peri-implant tissue from rough surface implants at 7 days were not arranged in parallel orientation but in an irregular a "cotton-ball-like." The levels of mRNA of types III and XII collagen and transforming growth factor-β1 significantly increased in the smooth implant group compared with the rough implant group at both 4 and 7 days or either one of days. The results of this study suggest that implant surface characteristics may affect early events of soft tissue healing by influencing collagen fiber orientation and expression of key genes for initial healing.