Discussion
agitation, postoperative pain, tooth type, pain
LEAKAGE
Multiple factors may cause post-endodontic pain such as age, gender, tooth type, presence of periapical radiolucency, presence of preoperative pain and occlusal reduction [The double-blind technique was applied in the present study. The patients and evaluating clinicians were blinded about the administered treatment procedure. In addition, the statistician did not have any information about the group characteristics during the analysis. The groups were identified by assigned numbers. It has been reported that dental configurations, analgesics, and pre-operative pain are the factors related with occurrence of incidence of PP. Thus, to facilitate standardization and objectivity, the patients who has mandibular first premolar teeth treatment has been included in the present study. In addition, they had no pain and did not use analgesics before treatment. Retreatment was performed at a single visit because of the possibility of leakage of the temporary filling materials [NaOCl is a widely used irrigation solution because of its antimicrobial and tissue-dissolving effects. It can be used in concentrations of 1 to 5.25%. High concentrations might increase the toxic effects on periradicular tissues [and cause PP. Therefore, in the present study, a 2.5% NaOCl concentration was preferred to obtain the optimum benefits from its antimicrobial effects while minimizing its toxic and PP-inducing effects. The standardization of study protocols can mitigate the effects of intraoperative variables on outcomes.Periapical radiolucency has been found to cause PP lasting two or more days [A meta-analysis study investigated the PP incidence after instrumentation with rotary and reciprocating root canal file systems andstated that the rotary instruments are associated with a lower incidence of PP than reciprocating instruments [In both groups in our study, pain was the most intense at the 12th h. It then gradually decreased. A comparison of the groups indicated that EDDY resulted in significantly more postoperative pain at 12, 24, 48, and 72 h. There was no significant difference between the two groups during the first week. Therefore, the null hypothesis was partially rejected. Considering the evaluation within the group, the PP levels in the first group were significantly higher at the 12th h and minimal after the 24th h. In the second group, the pain level further decreased after the 48th h. In the present study, a score of 7 to 10 was considered to represent severe pain, which was characterized as a flare-up [A review of the literature yielded two in vitro studies on the creation of apical extrusion upon usingEDDY. EDDY was found to cause significantly more apical extrusion than ultrasonic, mechanical, and positive pressure agitation techniques [In the current study, postoperative pain severity was evaluatedafter 12, 24, 48, 72 h sand 7 days with a composite measure of patient-reported and clinician-reported outcomes, that included pain scale and clinical examination in accordance with the recent clinical guidelines [The effects of gender on PP are controversial. Some studies have reported more incidence of PP in women[The factors in pain incidence and severity remain unclear. Studies in which pain is assessed have limitations. Thus, the present study aimed to objectively evaluate a subjective experience that might be influenced by individual variability. A limitation of the present study is that a sham was not administered after the treatment to prevent the initial levels of PP from taking analgesic.The value of our work lies in the designand validity of the methodology. Randomized controlled trials represent most scientifically rigorous method of hypothesis testing in evidence-based medicine. Despite that the findings cannot be generalized to allretreatment cases, the findings extend our knowledge and add to a growing body of literature onPP after the use of EDDY and MDA activation techniques in non-surgical retreatment. Future investigations designed as split-mouth studies,are suggested, to eliminate individual variabilities.