Many researchers are interested in wound healing in the t reatment of burns, prevention of post surgical adhesions and cosmetic s urgery by excess collagen production and scar formatlOn Synthetic epidermal substi tutes with cultured epi thelial cells seem to be an attractive strategy since keratinocytes have been demonstrated to modulate fibroblast growth and collagen synthesis. Bioa bsorbable and biocompatible chitosan structurally mimics hyaluronic acid. Recently, a bio compatible synthesi zecl ch itosa n-PVP(polyvinyl pyrrolidone) hydrogels demonstrated in vitro biocompat ibi li ty for bio medical applications . However. there is no re port on this hydrogeJ"s ability to modulate human gingival fibroblast growth. The purpose of this study were to investigate different growth modulation between human gingival fibroblast and normal human oral keratinocyte by chitosan- PVP hydrogel, and to apply this biocompatible synthetic polymer to oral and maxillofacial wound healing. We have synthesized a hydrogel from chitosan-PVP and examined its effect on human gingival fibroblast growth modulation in vitro. Non-toxic and biocompatible hydrogel with human gingival fi broblasts and epithelial cells was tested by MTT assay. HGF showed a higher growth proliferation than that of NHOK after cell seeding. In MTT assay, 30% hydrogel leach out products showed a higher cellular viability in NHOK than that of any other products. In MTT assay, 30% hyclrogel leach out products showed relatively lower cellular viability of HGF ln growth profile, NHOK showed about 7 fo lcls higher than HGF after 1 day, while about 2 fo lds higher after 5 days. And also NHOK showed above about 70% cell ular via bility from 1 to 7 days. It suggested that Chitosan-PVP hydrogel would inhibit relatively the growth of HGF and s timulate the growth of NHOK_ This phenomenon may prove to be of use in wound management 0 1' oral and maxillofacial area as epitheli al substitutes.

Periodontitis is a chronic infectious disease that leads to periodontal destruction, and is one of the major causes of tooth loss in humans. The osteoclast differentiation factor (ODF), which is also known as the receptor activator of the NF-kB ligand (RANKL), is a surface-associated ligand on bone marrow stromal cells and osteoblasts. RANKL activates its cognate receptor, RANK, on osteoclast progenitor cells, which leads to the differentiation of mononucleated precursor cells. Osteoprotegerin (OPG) is a decoy receptor that is released from stromal cells and osteoblasts to inhibit the interaction between RANKL and RANK. Although the precise mechanism of bone loss in periodontitis is unknown, the differentiation and activation of osteoclasts by OPG-ODF-RANK signaling might play the role in periodontal bone destruction. The relationship between the concentration of sex hormones and the expression of ODF and OPG was examined by treating human gingival fibroblasts and periodontal ligament cells with the normal serum concentration of estrogen or progesterone during menstruation or at menopause. The ODF/OPG relative ratio was elevated at the concentration observed during ovulation in human gingival fibroblasts and at the concentration observed between ovulation and menstruation in periodontal ligament cells treated with estrogen. However, the ratio was <1 at all concentrations in both cells treated with progesterone. In the case of menopause simulated by estrogen depletion, the ratio was <1 in human gingival fibroblasts but >1 in periodontal ligament cells.

The aim of this study was to investigate the cytotoxicity of dental casting gold alloys. Recently, "biocompatability" is considered the most important requirement of dental materials. Dental metals and alloys were estimated by quantity of released ions, which had influenced to living tissues. The requirement of using normal human cells for cytoxicity strudy were abruptly increased. We used the cultured normal human gingival fibroblasts to estimate the cytotoxicity of dental casting gold alloys. The product of S company(Korea, AIGIS-SOFT, AIGIS-PLUS, AIGIS-A, AIGIS-PT, experimental group) and D company's (German, Biocclus inlay, Biolor SG, Stabilor NF Ⅳ, Degulor B, control group) dental casting gold alloys were used. The morphological investigation, hemolysis test, MTT assay and SRB assay were done in vitro. In vivo, inflammatory reaction in rat was examined for 2 weeks. 1. In the result of cytotoxicity assay, there were some differences but was no significancy among the results between two group's hemolysis, MTT and SRB assay. 2. The gingival fibroblasts attached to the surface of dental casting gold alloy showed various features and increased in number as the time had passed. 3. In vivo, chronic inflammatory cell infiltration was prominent from 3 days to 1 week and inflammation was reduced as time had gone. From the aboving results, there were no significant differences in cytoxicity depending on the ratio of gold content, but showed differences depending on the ratio of total precious and non-precious metal content between two groups. In vitro study showed few differences in inflamation reaction.