Stereomicroscope Analysis of the Cleaning Capacity of an Abrasive-Expansive System in Oval Canals: A Laboratory Study

Background: The aim of this study was to evaluate, by means of a stereomicroscope, the influence on the removal of smear layer obtained by the XP-endo Finisher and Tornado Disinfection Kit systems during the final agitation of the irrigating solution, in conservative preparations. Materials and methods: Ten extracted human lower premolars were chemically-mechanically prepared with the ProDesign Logic 2 NiTi rotary system (25/.05) and 2.5% NaOCl. The same specimens were submitted to three different protocols of agitation of the irrigating solution: Conventional irrigation, XP-endo Finisher and Tornado Disinfection Kit. For this, a closed system was made, the roots were cleaved and three holes were made in each third of the root canal and filled with dentinal debris to take initial photos under a stereomicroscope. The amount of debris was rated using a 4-point scoring system. The data obtained were submitted to the Wilcoxon, Kruskal-Wallis and Dunn tests (p<0.05). Results: In the analysis of the effectiveness of each protocol, it was possible to observe a statistically significant difference in the removal of debris in all thirds for all protocols (p<0.05). Regarding the difference in score found before and after application of the protocol, a significant difference was observed between the apical and the middle third in the Tornado Disinfection Kit group (p<0.05) and there was no difference between the same third for different groups (p>0.05). Conclusion: Based on the methodology and the results presented, it was concluded that both evaluated protocols improved the cleaning of root canal recesses in all thirds, with no difference between them