Smear layer removal with passive ultrasonic irrigation and the NaviTip FX: a scanning electron microscopic study

Objective. The aim of this study was to compare the effect of continuous, intermittent passive ultrasonic irrigation (PUI) and active scrubbing of irrigants with NaviTip FX (Ultradent, South Jordan, UT) in removing smear layer. Study design. Forty single-rooted teeth were randomly divided into 5 test groups and subjected to final irrigation with 17% EDTA followed by 2.5% NaOCl for 1 minute each using different activation methods: no activation (control), brushing with NaviTip FX, continuous PUI with irrigant delivered at pulp chamber, continuous PUI with irrigant delivered through the ultrasonic unit, and intermittent PUI. Specimens were examined under scanning electron microscope, and the data were analyzed using Friedman 2-way analysis of variance, Kruskal-Wallis, and Mann-Whitney U tests. Results. NaviTip FX and intermittent PUI showed significantly lower smear score than other groups at the 3 mm level (P < .05). Conclusions. Both brush and intermittent ultrasonic activation were effective in the removal of smear layer from the apical third. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: 465-470)