Radix entomolaris in a mandibular second molar

a case report

Abstract

Introduction: Endodontics is a specialty of dentistry that aims to clean the root canals, removing pulp remnants and microorganisms, and consequently seal the pulp cavity to promote the repair of periapical tissues. However, the anatomical complexity of root canals is challenging for endodontists. The root canal system can present significant anatomical variations that require more detailed planning. One such variation is the presence of an additional root, known as radix, which can occur in lower molars. This anatomical variation presents two main types: radix entomolaris (RE), located distolingually, and radix paramolaris (RP), located mesiobuccally. While the presence of radix entomolaris is relatively common in the mandibular first molars of some ethnic groups, it is a rare occurrence in mandibular second molars. This fact increases the complexity of endodontic treatment, requiring an even more meticulous approach by the professional. Technological advancements in endodontics have increased the success rate in treating these teeth with more complex anatomy. It is essential to carefully analyze conventional or digital radiographs and perform a detailed clinical examination for the accurate diagnosis of these variations. Cone beam computed tomography (CBCT) is an effective method for identifying these anatomical variations, although it is not always the first choice in clinical practice due to its cost and availability. Objective:  To report a clinical case of radix entomolaris in a mandibular second molar. Case Description: This case report addresses an endodontic retreatment involving the presence of radix entomolaris (RE) in a mandibular second molar, performed in the Postgraduate Course in Endodontics located at the Instituição de Estudos da Saúde e Gestão Sérgio Feitosa (Belo Horizonte/MG). For the diagnosis, a cone beam computed tomography (CBCT) was performed, which revealed the presence of an untreated supernumerary root in the mandibular second molar (47). During the initial appointment, after the anamnesis and clinical examination, coronal access was performed, and the filling material was removed using Easy Bassi retreatment files. The extra root was located and instrumented with a Logic 2 25/05 rotary file (Easy Bassi) and with the aid of 3.5x magnification loupes. After instrumentation and intracanal medication with Ultracal (Ultradent) for 30 days, in the following session, the canals were filled with zinc oxide eugenol cement (Endofill-Dentsply), using the single cone technique for the supernumerary root and the Tagger hybrid technique for the other canals. The procedure was performed with extreme care to ensure complete cleaning and sealing of the root canals. Results: Knowledge of anatomical variations is crucial for endodontic success, therefore, the presence of a third root in lower molars can result in the failure of the initial treatment due to the difficulty of visualization and instrumentation. CBCT is essential for an accurate diagnosis and minimization of risks during retreatment. This case highlights the importance of CBCT in identifying complex anatomical variations, such as radix entomolaris. Additionally, the use of advanced techniques and instruments allows for effective retreatment, increasing the chances of clinical success and tooth preservation. Conclusion: The presence of radix entomolaris in mandibular second molars is rare, making diagnosis and treatment more challenging. The literature suggests that over 90% of mandibular second molars have two roots and three canals, further highlighting the rarity of radix entomolaris. Therefore, diagnostic accuracy and anatomical knowledge were essential for endodontic success in this specific case. Early identification of variations such as radix entomolaris, through advanced diagnostic methods like CBCT, can prevent failures in initial treatment and ensure a better prognosis for the patient. This case exemplifies the importance of constant updates for endodontic professionals, in light of anatomical variations and technological advancements in the field.