This study was conducted to determine the frequency of posterior teeth with root canal therapy in orthodontic patients and to focus on the orthodontics consequences. This retrospective study evaluated 550 OPGs for posterior teeth that had received endodontic treatment. A comprehensive online electronic database provided the data. In orthodontic patients, cross-validation was performed using the clinical data for RC treated posteriorly. 8.7% of the orthodontic population had posteriors that had undergone endodontic treatment. The maxillary first molar, followed by mandibular first molars made up approximately 46% of all root-canal-treated posterior teeth. Males and females with and without posteriors treated with RC differed significantly. Compared to women, men have more posteriors that have had endodontic treatment (P > 0.1). Many orthodontic patients have posteriors that have undergone RC treatment. The frequently managed posterior teeth with endodontic therapy are mandibular first molars. Because anchoring needs are high on treated posterior teeth, they must be thoroughly evaluated before orthodontic treatment. To achieve physiologic and effective therapy, treatment mechanics should be modified and treatment protocols should be integrated.
