Numerical Investigation of Irrigant Flow Characteristics for Manual Endodontic Debridement

Root canal therapy or endodontic treatment is a nonsurgical approach used to remove the infected pulp, disinfect, and reshape the canal. Despite more than a century of technological improvements in root canal procedures, clinical studies indicate that microbial flora remain in the canal following standardized cleaning and shaping procedures using antimicrobial irrigants. Unfortunately, accessing this ‘dead zone’ in the apical third has been challenging given the large number of parameters that govern the flow pattern. Computational fluid dynamics (CFD) presents a powerful tool to investigate flow behavior in areas where experimental measurements are difficult to perform. This paper is divided into two sections. First, the influence of irrigant flow rate and needle insertion depth on velocity characteristics are computationally investigated for a simplified root geometry. The needle type considered is a 30 gage KerrHawe with a side vent for fluid discharge. The simplified root canal was modeled as a frustum with a length of 18 mm, diameter of 1.59 mm at the orifice, and a diameter of 0.45 mm at the apical constriction (6.5% taper). Following this, a more realistic root geometry is used to investigate how the results from part 1 scale with root geometry.