Comparison of crown down and step down instrumentation techniques on postoperative pain in lower first and second molars with asymptomatic irreversible pulpitis using RaCe rotary instruments: A randomized clinical trial

Abstract

Dental practitioners are always looking for instrumentation techniques to reduce extrusion of debris in order to alleviate pain in root canal treatment. The purpose of this study was to compare the effect of crown-down and step-down instrumentation techniques on post-operative pain in lower first and second molars with asymptomatic irreversible pulpitis using RaCe rotary system. Materials and Methods: 70 patients who passed the inclusion and exclusion criteria were randomly divided into 2 groups according to the root canal instrumentation technique used, crown-down or step-down. All root canal treatments were done in one appointment by a single operator, and the severity of postoperative pain was evaluated with visual analog scale (VAS) at 6-, 12-, 24-, 48-, and 72-hour and 1-week internals. Repeated measures ANOVA was used to calculate data at 0.05 significant level.Results: The mean ± SD of pain severity at 6-, 12-, 24-, 48- 72 and 168-hour internals were 20.6±4.2, 16.6±4.1, 14.9±3.8, 11.4±3.9, 8.9±3.4, 2.4±1.5 in crown-down group and 15.8±3.2, 12.4±3.1, 11.9±3.1, 10.3±3, 7.8±3.2, 1.9±0.8 in step-down group respectively. There was no significantly difference between crown-down and step-down groups (P = 0.512), although in both groups pain level had significantly decreased by 12, 24, 48, 72and 168 hours (P <0 .05). There was no significant difference in postoperative pain between the crown-down and step-down groups at any time intervals (p=0.770).Conclusion: There was no significant difference in postoperative pain severity between crown-down and step-down instrumentation techniques of RaCe rotary system, in mandibular first and second molars with asymptomatic irreversible pulpitis.