不同冲洗液及冲洗时间对牙本质微硬度的影响

目的:比较不同冲洗液对牙本质微硬度影响。方法:收集新鲜拔取上颌前牙60个,并沿在釉牙本质界截去牙冠,进行根管预备。再将处理好的牙根沿牙体长轴纵向切开分为两部分。再将得到的120个样本分为5组,分别用5.25%NaOCl、2.5%NaOCl、2%洗必泰、3%H2O2和生理盐水处理5min、10min或15min。然后用微硬度测定仪检测根管牙本质的微硬度。结果:5.25%NaOCl、2.5%NaOCl和3%H2O2冲洗都降低了牙本质微硬度。同样冲洗时间里,5.25%NaOCl组牙本质微硬度较2.5%NaOCl都低,且牙本质微硬度随冲洗时间增加降低。2%洗必泰对牙本质微硬度没有产生影响。结论:采用2%洗必泰冲洗或控制次氯酸钠溶液的浓度和冲洗时间可减少冲洗液对牙本质微硬度的影响。

Effect of Different Endodontic Irrigation and Rinsing Time on Microhardness of Dentin

Objectives:To evaluate the effect of several endodontic irrigation solutions on the microhardness of root canal dentin.Methods:Sixty freshly extracted maxillary incisors were used in this experiment.The crowns of teeth were sectioned at the cemento-enamel junction.The root canals were instrumented and separated longitudinally into two segments.A total of 120 specimens were divided equally into five groups.The specimens were irrigated with 5.25% NaOCl,2.5% NaOCl,0.2%chlorhexidine,3%H2O2 and saline separately for 5min,10min or 15min.After irrigation,the microhardness of the dentine was measured.Results:5.25% NaOCl,2.5% NaOCl and 3%H2O2 decreased the microhardness of root dentine,and at all irrigation periods the microhardness of dentin in 5.25% NaOCl group was lower than that of 2.5% NaOCl group.Increasing irrigation time led to decrease in the microhardness of dentin.Conclusion:Choosing 0.2%chlorhexidine or controlling the concentration and irrigation time of NaOCl might reduce the harmless effect of irrigation on the microhardness of root canal dentin.