Effects of crosslinked dextran in hydroxylpropyl methylcellulose on soft tissue augmentation in rats.

This study compared crosslinked dextrans in hydroxylpropyl methycellulose (DiHMs, pH 5 or 7) with polymethylmethacrylate in bovine collagen (PMMA) and hyaluronic acid (HA) fillers on soft tissue augmentation and safety in rats. HA tended to maintain its size throughout the experimental period but was moveable and friable because of a lack of thick fibroconnective tissue formation. Although, PMMA induced moderately thick fibroconnective tissue formation, its size was decreased markedly from 3-week postimplantation (PI) and became the smallest at 24-month PI. DiHM (pH 7) elicited strong fibrous encapsulation around the filler. Its size decreased slowly but was still considerably maintained at 24-month PI. In contrast, the rate of the DiHM (pH 5) size decrease was slower than that of PMMA, faster DiHM (pH 7), but comparable to HA. Immunohistochemically, types I and III collagens were deposited inside and outside DiHMs (pH 5 and 7). DiHMs (pH 5 and 7), PMMA, and HA showed no adverse reactions. These results suggest that DiHM (pH 7) assures efficacy and safety and is a good candidate for soft tissue augmentation in both humans and animals.