Abstract:

Ultrasonic irrigation has been increasingly used in root canal therapy. The oscillating ultrasonic tips can induce cavitation and acoustic streaming，which can produce shear stress along the root canal wall and remove debris and bacteria. Nickel-titanium tips can adjust the anatomic modality of root canal preferably. There is no significant difference between a smooth wire and a cutting K-file as the ultrasonic tip on the removal of dentine debris and smear layer. Passive ultrasonic irrigation（PUI）removes more bacteria，smear layer and dentine debris and is an important supplement for cleaning complicated root canal system. Irrigation with sodium hypochlorite is effective. The use volume of irrigation is more important than density. PUI with a pulsation pattern is more effective in removing dentine debris than a continuous oscillation. The insertion direction and depth of the ultrasonic tip are affective. In this paper the mechanism of action，instrumentation，efficiency and relevant factors of PUI were reviewed in order to guide the practical application.

Key words: ultrasonic irrigation, ultrasonic tips, dentine debris, irrigant, cleaning effects

摘要：

超声冲洗在根管治疗术中的应用越来越多。超声工作尖震动使冲洗剂产生空穴作用和声流作用，所产生的剪切力可清除根管壁上的牙本质碎屑及生物物质。镍钛工作尖能更好地顺应根管解剖形态。工作尖为光滑或K锉形态对牙本质碎屑和玷污层的清洁效果无明显区别。超声冲洗能更好地清除根管内的细菌、玷污层和牙本质碎屑等，并对根管内的复杂结构有更强的清洁效果。超声冲洗选用次氯酸钠为冲洗剂可取得良好效果。冲洗液的使用量较其浓度更为重要，间断冲洗比连续冲洗更有效。超声工作尖插入的方向和深度亦会对冲洗效果产生影响。现从超声冲洗的作用机制、仪器设备、冲洗效果和影响因素等方面做一总结，以指导临床实践。

关键词: 超声冲洗, 超声工作尖, 牙本质碎屑, 冲洗剂, 清洁效果