Abstract: ［Abstract］ Objective〖HTSS〗〓To investigate the effect of ultrasonic curettage and tinidazole flushing on curative effect and gingival crevicular fluid factor level in patients with chronic periodontitis.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓One hundred and sixty  patients with chronic periodontitis were selected and randomly divided into study group and control group, 80 cases in each group. Study group were treated with ultrasonic scraping synchronous tinidazole, control group scraping were treated with ultrasound scraping cure synchronous distilled water intervention. The plaque index(PLI), periodontal depth(PD), bleeding on probing(BOP) and attachment level(AL) were observed before and 4 weeks after gingival scaling, and the efficacy was evaluated. Gingival crevicular fluid samples were collected before and 4 weeks after gingival scaling, Enzyme linked immunosorbent assay was used to detect interleukin 8(IL8), matrix metalloproteinase 8(MMP8) and tissue inhibitor of matrix metalloproteinase 1( TIMP1) level.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓After curettage, the PLI, PD, BOP and AL in the study group were lower than those before the treatment and the control group, the total effective rate was better than the control group(P＜005). The level of IL8, MMP8 and TIMP1 in the study group was lower than that before the treatment and the control group(P＜005).
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓Ultrasonic subgingival scaling and synchronous tinidazole flushing can significantly reduce the levels of IL8, MMP8 and TIMP1 in gingival crevicular fluid factor in patients with chronic periodontitis and effectively relieve the inflammatory reaction, with significant clinical effect and clinical value.

Key words: periodontal diseases, tinidazole, cytokines