Morphology of the Second Mesiobuccal Canal in the Maxillary Second Molar / Morfología del Segundo Canal Mesiovestibular en el Segundo Molar Maxilar

SUMMARY: Failure to locate a complete canal system affects the prognosis of root canal treatment. A missed root canal is one of the most common reasons for failed root canal treatment. The prevalence of the second mesiobuccal canal in the maxillary second molar is relatively high and has a variety of configurations. Therefore, knowledge of its morphology is required in clinical endodontics. This review presented the canal in terms of its prevalence, classification, anatomical features, and the method for locating the second mesiobuccal canal in the maxillary second molar. Root canal treatment requires knowledge of tooth morphology, appropriate access preparation, and a thorough examination of the tooth's interior. Thus, clinicians should carefully employ various methods for assessing the anatomy of the entire root canal system to prevent failure in locating the second mesiobuccal canal. This canal can be located by modifying the access cavity design and utilizing specific instruments to improve the second mesiobuccal canal system visualization.

La falta de localización de un sistema completo de canal afecta el pronóstico del tratamiento de éste. La omisión de un tratamiento de canal es uno de los motivos más frecuentes por las que el tratamiento de canal fracasa. La prevalencia del segundo canal mesiovestibular en el segundo molar superior es relativamente alta y tiene una variedad de configuraciones. Por tanto, el conocimiento de su morfología es necesario en endodoncia clínica. Esta revisión presentó el canal en términos de su prevalencia, clasificación, características anatómicas y el método para localizar el segundo canal mesiovestibular en el segundo molar superior. El tratamiento de canal requiere conocimiento de la morfología del diente, una preparación adecuada del acceso y un examen exhaustivo del interior del diente. Por lo tanto, los dentistas deben emplear cuidadosamente varios métodos para evaluar la anatomía de todo el sistema de canales radiculares para evitar fallas en la localización del segundo canal mesiovestibular. Este canal se puede localizar modificando el diseño de la cavidad de acceso y utilizando instrumentos específicos para mejorar la visualización del sistema del segundo canal mesiovestibular.

Identification and Characterization of a Previously Undiscovered Anatomical Structure in Maxillary Second Molars: The Palato-Mesiobuccal Canal.

INTRODUCTION: This report aims to communicate the discovery of a novel anatomy in a 3-rooted maxillary second molar, named as palato-mesiobuccal canal. METHODS: The tooth selected for this report was found incidentally as a result of a study on extracted maxillary molars that was being conducted for an unrelated purpose and involved hundreds of teeth. This 3-rooted maxillary second molar was scanned using a micro-computed tomography device set at a pixel size of 13.68 µm. The images were reconstructed with previously tested parameters resulting in the acquisition of 1655 axial cross-sections. Three-dimensional (3D) models of the internal and external anatomies were generated in Standard Tessellation Language (STL) format and were texturized to simulate the pulp tissue. The inner structure of the tooth was analyzed through the axial cross sections and the 3D volume was qualitatively evaluated. RESULTS: The analysis of the 3D models revealed that the maxillary second molar under examination has 3 independent roots and 4 root canals. Each root (mesiobuccal, distobuccal, and palatal) contains 1 canal, while the fourth canal follows a unique path, originating in the coronal third of the palatal canal and proceeding in a buccal direction ultimately exiting through an independent foramen at the apex of the mesiobuccal root, near the mesiobuccal canal. CONCLUSIONS: This brief communication reports the discovery of a novel anatomy in a 3-rooted maxillary second molar, named as palato-mesiobuccal canal, and provides important insights into the complexity of the root canal system in this group of teeth.

Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases.

Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction.

Cone-beam computed tomography study of prevalence and location of MB2 canal in the mesiobuccal root of the maxillary second molar.

The maxillary second molar (2 MM) has the most complex root canal system, and a high percentage of treatment failures is due to the impossibility of locating, instrumenting and obturating the second mesiobuccal canal (MB2). The aim of this study was to describe in vivo the prevalence and location of the MB2 canal in the mesiobuccal root of the permanent maxillary second molar through CBCT image analysis. Two hundred twenty five CBCT images of 2 MM were studied. In the presence of the MB2 canal, the floor of the coronal cavity was located and advanced every 1 mm apically to standardize observation. The geometric location in relation to the primary mesiobuccal (MB1) and palatal (P) canals was done by locating the central points of the canal and projecting a line between them, together with a perpendicular line between MB1-P (point T). The data were analyzed using descriptive statistics, with a value of P < 0.05 being statistically significant. The MB2 canal was identified in 48% of the cases. It was located 2.2 ± 0.54 mm palatally and 0.98 ± 0.35 mesially to the MB1 canal. The average age of the subjects where it was found was 26.36 ± 10.85 years. Its location was more frequent in men (63%), and no differences were observed in its appearance in the hemi-arch. It is necessary to know the high probability of finding the MB2 canal in the maxillary second molar, and the CBCT is a good diagnostic tool for its detection and exploration.

A study of the distobuccal root canal orifice of the maxillary second molars in Chinese individuals evaluated by cone-beam computed tomography

As is commonly understood, the root canal morphology of the maxillary molars is usually complex and variable. It is sometimes difficult to detect the distobuccal root canal orifice of a maxillary second molar with root canal treatment. No literature related to the distobuccal root canals of the maxillary second molars has been published. Objective: To investigate the position of the distobuccal root canal orifice of the maxillary second molars in a Chinese population using cone-beam computed tomography (CBCT). Material and methods: In total, 816 maxillary second molars from 408 patients were selected from a Chinese population and scanned using CBCT. The following information was recorded: (1) the number of root canals per tooth, (2) the distance between the mesiobuccal and distobuccal root canal orifice (DM), (3) the distance between the palatal and distobuccal root canal orifice (DP), (4) the angle formed by the mesiobuccal, distobuccal and palatal root canal orifices (∠PDM). DM, DP and ∠PDM of the teeth with three or four root canals were analyzed and evaluated. Results: In total, 763 (93.51%) of 816 maxillary second molars had three or four root canals. The distance between the mesiobuccal and distobuccal orifice was 0.7 to 4.8 mm. 621 (81.39%) of 763 teeth were distributed within 1.5-3.0 mm. The distance between the palatal and distobuccal orifice ranged from 0.8 mm to 6.7 mm; 585 (76.67%) and were distributed within 3.0-5.0 mm. The angle (∠PDM) ranged from 69. 4º to 174.7º in 708 samples (92.80%), the angle ranged from 90º to 140º. Conclusions: The position of the distobuccal root canal orifice of the maxillary second molars with 3 or 4 root canals in a Chinese population was complex and variable. Clinicians should have a thorough knowledge of the anatomy of the maxillary second molars.