Background: An untreated root canal in an endodontically treated tooth can lead to periapical lesions which can ultimately result in necrosis and inflammation of the pulp or destruction of periodontal tissues. This study was conducted to determine the prevalence of periapical radiolucency in endodontically treated teeth with untreated canals identified by CBCT.
Materials and Methods: In this analytical cross-sectional observational 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 the Faculty of Dentistry of Azad University of Isfahan (Khorasgan) were examined. The study recorded the number of teeth and roots, presence/absence of periapical lesions, and untreated canals. Data were analyzed using chi-square and Fisher's exact tests (α=0.05).
Results: A total of 38 cases (4.9%) showed untreated canals, with the second mesiobuccal canal being the most common type (57.9%) and the maxillary first molar having the highest number of untreated canals (52.6%). In 125 canals (16.1%), apical periodontitis lesions were detected. There was a significant difference between the frequency of untreated canals in the endodontically treated maxillary premolars and molars, mandibular premolars, and molars (p<0.05). Similarly, there was a significant difference in the frequency of apical periodontitis between endodontically treated maxillary premolars and molars, and mandibular premolars and molars (p<0.001).
Conclusion: Apical periodontitis is more common in the second mesiobuccal canal of maxillary first molars that have not undergone successful root canal treatment