Histologic evaluation of skin-derived and collagen-based substrates implanted in palatal wounds

Tissue shortage complicates the surgery of cleft lip and palate anomalies and the healing of defects on the palate impairs growth of the dento-alveolar complex due to scar tissue formation. Implantation of substitutes into the wound area might overcome this adverse effect. The aim of this study was to compare the tissue response to three collagen-based (collagen type I substrate alone, or collagen coated with elastin or chondroitin-6-sulfate) and two skin-derived substrates (unprocessed dermis and AlloDerm) after implantation into 12 dogs. Histology was performed at 3, 10, and 20 days postsurgery. We showed that all substrates were well tolerated. However, it is unclear whether AlloDerm was rapidly degraded or if it was sequestrated. There was no elastin or collagen present in these wounds. All collagen-based substrates showed good epithelial regeneration, although heparan sulfate (JM 403) was absent. Wounds treated with the collagen-based substrates contained fewer myofibroblasts at 20 days postsurgery and the type III collagen fibers in the immature scar tissue were more randomly oriented than in an untreated wound. In conclusion, palatal wounds with a dermal substrate heal with fewer indications of scar tissue formation and evoke only a mild inflammatory reaction, which is preferred over the tissue reaction in an untreated wound.