Assessment of postoperative pain after reciprocating or rotary NiTi instrumentation of root canals: a randomized, controlled clinical trial

The aim of this study was to assess postoperative pain in a prospective randomized clinical trial comparing two groups, using the ReciprocA (R) system in one group and the ProTaperA (R) rotary system in the other. The study included 78 male patients, aged 18-64 years (mean age of 26 years), with asymptomatic pulp necrosis in mandibular molar teeth (n = 78). The single-session endodontic treatment was performed by a single operator specialized in Endodontics. Mechanical preparation of the root canals was performed using the ProTaperA (R) and ReciprocA (R) instrumentation techniques. Postoperative pain was recorded using a verbal rating scale (VRS) and verbal description with well-defined categories at the three following time intervals: 24 h, 72 h, and 7 days after the endodontic procedure. The assessment of postoperative pain was recorded as no pain, mild pain, moderate pain, and severe pain or flare-up. Data were analyzed using the nonparametric Mann-Whitney test with the aid of the STATAA (R) software. The incidence of postoperative pain in the ProTaper group (PT) 24 h after the endodontic procedure was 17.9 and 5.1 % after 72 h. In the Reciproc group (RP), the incidence after 24 h was 15.3 and 2.5 % after 72 h. No patients presented severe pain at the time intervals assessed. No significant difference (p > 0.05) in postoperative pain was found between the ProTaperA (R) and ReciprocA (R) instrumentation technique during endodontic treatment in this study. According to our findings and the results of the clinical trial, the occurrence of postoperative pain was low and similar between the reciprocating and rotary techniques during the time intervals assessed. These results are different from basic laboratory studies that affirm that the reciprocating techniques tend to promote more postoperative pain since extrusion of debris is greater.