Evaluation of Root Canal Configuration of Maxillary Molars in a Brazilian Population Using Cone-beam Computed Tomographic Imaging: An In Vivo Study Emmanuel Jo~ ao Nogueira Leal Silva, DDS, MSc, PhD,* Yuri Nejaim, DDS, MSc, † Amaro I.V. Silva, DDS, MSc, † Francisco Haiter-Neto, DDS, MSc, PhD, † Alexandre A. Zaia, DDS, MSc, PhD, ‡ and Nestor Cohenca, DDS § Abstract Introduction: The aim of this study was to analyze and characterize root canal morphology of maxillary molars of the Brazilian population using cone-beam computed tomographic (CBCT) imaging. Methods: Patients referred for a CBCT radiographic examination for accu- rate diagnosis and treatment planning were enrolled in the study. A total of 620 healthy, untreated, fully developed maxillary first and second molars were included (314 first molars and 306 second molars). The following observations were recorded: (1) number of roots and their morphology, (2) number of canals per root, (3) fused roots, and (4) primary variations in the morphology of the root canal systems. Results: First and second molars showed a higher prevalence of 3 separate roots, mesiobuccal, distobuccal, and palatal, with 1 canal in each root (52.87% and 45.09%, respec- tively). Two canals in the mesiobuccal roots represented 42.63% of teeth, whereas mesiobuccal roots of second molars presented 2 canals in 34.32%. The most common anatomic variation in the maxillary first molar was related to the root canal configuration of the mesiobuc- cal root, whereas the root canal system of the maxillary second molar teeth showed more anatomic variables. Conclusions: Mesiobuccal roots of maxillary molar teeth had more variation in their canal system than the distobuccal or palatal roots. The root canal configu- ration of the maxillary second molars was more variable than the first molars in a Brazilian population. CBCT im- aging is a clinically useful tool for endodontic diagnosis and treatment planning. (J Endod 2014;40:173–176) Key Words Anatomy, cone-beam computed tomographic imaging, maxillary molars, morphology, root canal C omplete debridement, disinfection, and obturation of the root canal system are essential to increase the favorable outcome of root canal treatments. Therefore, cli- nicians should be aware of common root canal configurations and possible anatomic variations (1). Maxillary first molars have been frequently investigated because of their complex root anatomy and canal morphology (1–7). Based on the published results, it is generally accepted that most maxillary first molars have 3 roots and 4 canals (1–7). Most studies reported incidences of a second canal (MB2) in the mesiobuccal (MB) root in over 50% of the cases (4–9). Additional anatomic variations include distobuccal and palatal roots with more than 1 canal (8, 9) as well as C-shaped canals (10). Some commonly used methodologies to analyze canal morphology include root canal staining and tooth clearing (2, 11, 12), conventional and digital radiographs (13–15), and radiographic assessment enhanced with contrast media (16). Recently, cone-beam computed tomographic (CBCT) images have been found to be useful in providing accurate anatomic details in 3 dimensions for diagnosis and treatment planning before endodontic therapy (17, 18). CBCT acquires high- resolution imaging of the hard tissues of the maxillofacial region with faster and easier image acquisition (5). By providing a 3-dimensional representation of the maxillofacial tissues in a cost- and dose-efficient manner, a better preoperative assessment can be obtained for diagnosis and treatment, thus increasing the outcome of the therapy and avoiding further complications. Internal complexities of the root canal are genetically determined and have defin- itive importance in anthropology (19). From a genetic and ethnic perspective, the current Brazilian population is very diverse and considered to be one of the most het- erogeneous populations in the world, with an important genetic contribution from 4 main continental groups: Europeans, Africans, Asians, and Native Americans. A recent study characterized the anatomy of mandibular molars in a Brazilian population (20). However, there are no reports on the root and canal morphology of Brazilian maxillary molars. The aim of this in vivo study was to analyze and characterize the root canal morphology of maxillary molars in the Brazilian population using CBCT imaging. Materials and Methods CBCT images of 314 maxillary first molars and 306 second mandibular molars from 294 Brazilian people (108 men and 186 women) were identified in the database of the oral radiology department. They were referred to this department between From the *Department of Endodontics, School of Dentistry, Grande Rio University (UNIGRANRIO), Rio de Janeiro, Rio de Janeiro, Brazil; † Department of Oral and Maxillofacial Surgery, Oral Radiology Division, Piracicaba Dental School, State University of Campinas, Piracicaba, S~ ao Paulo, Brazil; ‡ Department of Restorative Dentistry, Endodontic Division, Piracicaba Dental School, State University of Campinas, Piracicaba, S~ ao Paulo, Brazil; and § Department of Endodontics, School of Dentistry, University of Washington, Seattle, Washington. Address requests for reprints to Dr Emmanuel Jo~ ao Nogueira Leal da Silva, Dental School, Grande Rio University, UNIGRANRIO, Endodontics Department, Rua Hero- tides de Oliveira, 61/902, Icara  ı, Niter oi, RJ, Brazil. E-mail address: nogueiraemmanuel@hotmail.com 0099-2399/$ - see front matter Copyright ª 2014 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2013.10.002 Clinical Research JOE — Volume 40, Number 2, February 2014 Maxillary Molar Anatomy in a Brazilian Population 173