Resident Southern Illinois University Alton, Illinois, United States
Abstract: The prognosis of endodontic treatment depends on accurate knowledge of the anatomy of the root canal system. Due to the complexity and variability of their root canal morphology, mandibular first premolars are difficult to access and treat. Missed anatomy can increase the percentage of failures after routine nonsurgical treatment as well as the incidence of flare-ups. The purpose of this retrospective radiographic study is to assess the prevalence of more than one root canal in mandibular first premolars in an Illinoisan subpopulation. A total of 538 patient records from Southern Illinois University School of Dental Medicine from 2016 through 2020 were evaluated. The results showed significantly higher percentages for both right and left mandibular first premolars than reported in the classic anatomic studies by Vertucci. For the right premolar, 35.9% of patients had more than one root canal, and for the left premolar, 37.7% of patients had more than one root canal. There was no significant difference between the right and left premolars. Our generalized mixed model analyses, with the patient as a random variable, indicated that neither sex, race, nor their interaction were predictors of the number of canals in the mandibular first premolars. This information corroborates the need for meticulous preoperative examination in cases of first mandibular premolars that require endodontic treatment to prevent procedural accidents that might lead to treatment failure and ultimately tooth loss..