Wall shear stress effects of different endodontic irrigation techniques and systems

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• 作者：Narisa Goode ; Sara Khan ; Ashraf A. Eid ; Li-na Niu ; Johnny Gosier ; Lisiane F. Susin ; David H. Pashley ; Franklin R. Tay
• 关键词：Apical fluid pressure ; Calcium hydroxide ; Canal fin ; Fluid flow rate ; Sodium hypochlorite ; Two-phase gas&ndash ; liquid flow
• 刊名：Journal of Dentistry
• 出版年：2013
• 出版时间：July, 2013
• 年：2013
• 卷：41
• 期：7
• 页码：636-641
• 全文大小：1424 K

文摘

Objectives

This study examined d¨¦bridement efficacy as a result of wall shear stresses created by different irrigant delivery/agitation techniques in an inaccessible recess of a curved root canal model.

Methods

A reusable, curved canal cavity containing a simulated canal fin was milled into mirrored titanium blocks. Calcium hydroxide (Ca(OH)₂) paste was used as debris and loaded into the canal fin. The titanium blocks were bolted together to provide a fluid-tight seal. Sodium hypochlorite was delivered at a previously-determined flow rate of 1 mL/min that produced either negligible or no irrigant extrusion pressure into the periapex for all the techniques examined. Nine irrigation delivery/agitation techniques were examined: NaviTip passive irrigation control, Max-i-Probe^? side-vented needle passive irrigation, manual dynamic agitation (MDA) using non-fitting and well-fitting gutta-percha points, EndoActivator? sonic agitation with medium and large points, VPro? EndoSafe? irrigation system, VPro? StreamClean? continuous ultrasonic irrigation and EndoVac apical negative pressure irrigation. D¨¦bridement efficacies were analysed with Kruskal-Wallis ANOVA and Dunn's multiple comparisons tests (¦Á = 0.05).

Results

EndoVac was the only technique that removed more than 99 % calcium hydroxide debris from the canal fin at the predefined flow rate. This group was significantly different (p < 0.05) from the other groups that exhibited incomplete Ca(OH)₂ removal.

Conclusions

The ability of the EndoVac system to significantly clean more debris from a mechanically inaccessible recess of the model curved root canal may be caused by robust bubble formation during irrigant delivery, creating higher wall shear stresses by a two-phase air-liquid flow phenomenon that is well known in other industrial d¨¦bridement systems.