Abstract: Objective: To explore the influence of gallnut extract as a root canal irrigants in the curative effect of chronic periapical periodontitis,and to clarify its mechanism. Methods: A total of 192 patients diagnosed with chronic periapical periodontitis were selected and randomly divided into control group (distilled water),hydrogen peroxide group,sodium hypochlorite group and gallnut extract group (n=48).In the process of root canal treatment,four irrigants were used respectively,then the curative effects 1 week,6 months,12 months after treatment were observed and compared. Results: After root filling treatment,the cold and heat stimulation of the tooth was insensitive in clinical examination,percussion(-),loose degree ≤ Ⅰ°,no swollen gums,bleeding on probing(-),no fistula,normal function of the exercise of chewing,decreased or disappeared transmission area in periapical bone in X-ray photo,and those metioned above were considered effective treatment.After 6 months of treatment,the effective rate in gallnut group was 89.4%,and there were no statistically significant differences compared with hydrogen peroxide group (91.1%) and sodium hypochlorite group(91.5%) (P>0.05),but there was significant difference compared with control group (67.4%) (P<0.05).After root filling treatment for 12 months,the effective rate in gallnut group was 83.7% and there were no statistically significant differences compared with hydrogen peroxide group(83.3%) and sodium hypochlorite group(87.8%) (P>0.05),but the ratio of tooth from improvement to recovery in gallnut group was higher than those in hydrogen peroxide group and sodium hypochlorite group. Conclusion: Gallnut extract as a root canal irrigants has good antibacterial and cleaning effect,and can achieve the aim of curing the chronic root periapical inflammation and preventing the infection.

Key words: chronic periapical periodontitis, root canal irrigants, gallnut extract, root canal therapy