Endodontic reintervention of a mandibular second premolar with four root canals: a case report

Complex anatomical variations on root canals morphology are one of the most arduous challenges in the endodontic practice. The objective of this case report is to discuss the clinical management of a mandibular left second premolar with four root canals and four distinct apical foramina. This case report has been written according to Preferred Reporting Items for Case reports in Endodontics (PRICE) 2020 guidelines. A 74-year-old patient was referred to retreat a left mandibular second premolar. The patient complained of discomfort when chewing hard food. After obtaining consent from the patient to investigate the symptoms, a thorough clinical and radiographic examination was performed. The main clinical findings observed were a moderate sensitivity to vertical percussion and mild discomfort at palpation. The periapical radiograph showed a fusion-like root with multiple canals and unsatisfactory root canal fillings associated with apical radiolucency. Based on this investigation, a diagnostic of persistent apical periodontitis was made to the tooth, and nonsurgical root canal re-treatment was proposed to the patient. After written informed consent was obtained, the procedure was performed under magnification provided by a dental operating microscope with the aid of ultrasonic tips. During the access opening and fillings removal, four root canal orifices were observed. Therefore, state-of-the-art technology such as the dental operating microscope, ultrasonics, and cone-bean computed tomography image are strong allies to manage anatomical variations.