Comparative Evaluation of the Effectiveness of Rotary and Reciprocating Single File Systems on Postoperative Pain After Biomechanical Preparation in Patients With Chronic Apical Periodontitis: A Randomized Clinical Trial.

Background and objective Postoperative pain after biomechanical preparation of root canals can be equally distressing to the patient as well as the dentist and can mold the patient's attitude and trust for future dental procedures. This randomized clinical trial aimed to evaluate the effectiveness of rotary and reciprocating single-file systems on postoperative pain after biomechanical preparation in patients with chronic apical periodontitis. Materials and methods In this randomized clinical trial (CTRI Reg No-CTRI/2021/04/032841), 94 patients with chronic apical periodontitis in single straight-rooted teeth were divided equally into two groups, according to a standardized protocol. Biomechanical preparation of the root canal was done by a single operator using the Hyflex Electrical Discharge Machining (EDM) rotary file system (Coltene, Altstätten, Switzerland) in group 1 and Reciproc Blue (VDW Dental, Munich, Germany) file system in group 2, respectively. Standardized instrumentation and irrigation techniques were followed in both groups. Participants (blinded to the instrumentation technique) rated their pain intensity at 24 hours, 48 hours, and 72 hours following the root canal instrumentation appointment using the Visual Analog Scale (VAS) and Numerical Pain Rating Scale (NPRS). Statistical analysis The number and time of analgesic intake were also recorded. The data was analyzed using repeated ANOVA, post hoc test, Student T-test, and independent T-test at a 5% level of significance with 80% power of the study. Results and discussion Both the file systems showed low mean postoperative pain intensity at all three time-points assessed. The mean pain value was found to be greater in the Hyflex EDM group at 24 hours, but less at 48 hours and 72 hours when compared to the Reciproc Blue group. However, this difference in pain values was not statistically significant at any of the assessed time points (p>0.05). No significant difference in pain was found based on gender and analgesic intake between the two groups (p>0.05). A low incidence of postoperative pain detected in this study can be attributed to the advanced endodontic devices and methods used during routine endodontic procedures, which provide more appropriate chemo-mechanical disinfection. Conclusion There was no statistically significant difference in postoperative pain between the rotary single file system and reciprocating single file systems at all the assessed time intervals. Hence, this study concluded that the instrumentation kinematics (single-file reciprocating or single-file rotary) had no impact on the intensity of postoperative pain after biomechanical preparation, and no file system is superior to the other in terms of postoperative pain, and hence, both file systems can be used clinically with equal efficiency when considering postoperative patient discomfort.