| Summary: | 碩士 === 中山醫學大學 === 口腔醫學研究所 === 90 === Fixed prosthodontic preparation often require subgingival margines because of caries, existing restoration, esthetic demand, or the need for additional retention. The gingival tissues must be displaced to allow sufficient impression material to be injected into the expanded gingival crevice. One of the most used methods to obtain gingival retraction is by means of medicated cord packed into the sulcus. Previous studies focus on the clinical operation and animal mode. Few article focus on the cytotoxicity of the cell. The cytotoxicity of gingival retraction cords must be investigated to ensure a safe biological response. The aim of this in vitro study was to evaluate the effect of gingival retraction cords impregnated with aluminum sulfate, dl-epinephrine and non-impregnated cord on human gingival fibroblast by in vitro. Human gingival fibroblasts from crown lenthening surgery were cultured by using an explant technique with the consent of the patient. Cytotoxicity, adhesion and proliferation of the cell were judged by using an assay of tetrazolium bromide reduction. The results showed that aluminum sulfate was cytotoxic to primary human fibroblast when compared to control group. But no significant difference noted among aluminum sulfate, dl-epinephrine and non-impregnated cord. Aluminum sulfate alone can inhibit cell adhesion. But dl-epinephrine inhibits cell proliferation very seriously even elute gingival retraction cord. No significant difference was found between aluminum sulfate and non-impregnated cord. This study suggests that gingival retraction cords containing epinephrine may not be better than cord containing aluminum sulfate. If dentists want to use the impregnated gingival retraction cord, we suggest to use the gingival retraction cord containing aluminum sulfate.
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