Backgrounds: Cryotherapy might help in reducing pain after root canal treatment. This study aimed to investigate the effect of different methods of cryotherapy on post-endodontic pain of one-visit root canal treatment in mandibular molar teeth with symptomatic irreversible pulpitis.Materials and Methods: This clinical trial study enrolled 60 patients with symptomatic irreversible pulpitis in a mandibular molar tooth. Before obturating the root canals, teeth were divided into four groups. Group 1: Control (without cryotherapy) Group 2: intracanal cryotherapy with final canal irrigation with 2.5 °C normal saline for 5 minutes, group 3: intraoral cryotherapy with the application of an ice pack 30 minutes inside the mouth and Group 4: extraoral cryotherapy. Patients’ post-endodontic pain was recorded on the first and third days. Data were analyzed by two-way analysis of variance, Tukey, and LSD post hoc test at the error level of 5%.Results: Pain reduction was highest, respectively, in the intracanal, control, and extraoral cryotherapy groups on the first and third days, although not significant (p>0.05). In each group, pain was reduced on the third day after treatment (P<0.05). Pain showed no relation to gender (p>0.05).Conclusion: Despite the limitations, based on the results of this study, the application of cryotherapy has a limited effect in reducing pain after root canal treatment. Time is more effective than cryotherapy in reducing pain. پرونده مقاله

Background: An untreated root canal in an endodontically treated tooth can cause periapical lesions and as a result necrosis and inflammation of the pulp or destruction of periodontal tissues. The aim of this study was to determine the prevalence of periapical radiolucency in endodontically treated teeth with untreated canals by CBCT.Materials & Methods: In this analytical cross-sectional study,a total of 326 maxillary and mandibular premolars and molars with 775 root canals with previous root canal treatment obtained from CBCT images from the archives of the Radiology Center of Azad University of Isfahan (Khorasgan) were examined.The number of teeth and roots, presence/absence of periapical lesions, and presence/absence of untreated canals were recorded. Data were analyzed using chi-square and Fisher's exact testsResults: Untreated canals were observed in 38 cases . The most common type of untreated canal was the second mesiobuccal canal (57.9%) and the maxillary first molar had the highest untreated canal . Apical periodontitis lesions were observed in 125 canals.There was a significant difference between the frequency of untreated canals in the endodontically treated maxillary premolars and molars, mandibular premolars, and molars. There was a significant difference in the frequency of apical periodontitis between endodontically treated maxillary premolars and molars, and mandibular premolars and molars.Conclusion:The frequency of apical periodontitis is most likely higher in the second mesiobuccal canal of maxillary first molars with no successful root canal treatment than in other teeth. پرونده مقاله