Study of Root Canal Anatomy in Human Permanent Teeth
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Brazilian Dental Journal (2015) 26(5): 530-536 ISSN 0103-6440 http://dx.doi.org/10.1590/0103-6440201302448 1Department of Stomatologic Study of Root Canal Anatomy in Human Sciences, UFG - Federal University of Goiás, Goiânia, GO, Brazil Permanent Teeth in A Subpopulation 2Department of Radiology, School of Dentistry, UNIC - University of Brazil’s Center Region Using Cone- of Cuiabá, Cuiabá, MT, Brazil 3Department of Restorative Dentistry, School of Dentistry of Ribeirão Beam Computed Tomography - Part 1 Preto, USP - University of São Paulo, Ribeirão Preto, SP, Brazil Carlos Estrela1, Mike R. Bueno2, Gabriela S. Couto1, Luiz Eduardo G Rabelo1, Correspondence: Prof. Dr. Carlos 1 3 3 Estrela, Praça Universitária s/n, Setor Ana Helena G. Alencar , Ricardo Gariba Silva ,Jesus Djalma Pécora ,Manoel Universitário, 74605-220 Goiânia, 3 Damião Sousa-Neto GO, Brasil. Tel.: +55-62-3209-6254. e-mail: [email protected] The aim of this study was to evaluate the frequency of roots, root canals and apical foramina in human permanent teeth using cone beam computed tomography (CBCT). CBCT images of 1,400 teeth from database previously evaluated were used to determine the frequency of number of roots, root canals and apical foramina. All teeth were evaluated by preview of the planes sagittal, axial, and coronal. Navigation in axial slices of 0.1 mm/0.1 mm followed the coronal to apical direction, as well as the apical to coronal direction. Two examiners assessed all CBCT images. Statistical data were analyzed including frequency distribution and cross-tabulation. The highest frequency of four root canals and four apical foramina was found in maxillary first molars (76%, 33%, respectively), followed by maxillary second molars (41%, 25%, respectively). The frequency of four root canals in mandibular first molars was 51%. Mandibular first premolars had two root canals and two apical foramina in 29% and 20% of the cases, respectively. Mandibular central and Key Words: Anatomy, root canal, lateral incisors and canines presented two root canals in 35%, 42% and 22% of the cases, root canal morphology, root canal respectively. The navigation strategy in CBCT images favors a better identification of treatment, root canal failure, cone frequency and position of roots, root canals and apical foramina in human permanent teeth. beam computed tomography. Introduction (1,6-8,10,11). Innovative alternatives to study internal Root canal treatment involves different operative steps, root canal anatomy, such as CBCT and MCT have been and one of the great challenges is to know the details proposed (1,6-12). against the internal spaces individual of each human tooth. Matherne et al. (10) evaluated the use of CBCT as a The success of cleaning, shaping and root canal filling diagnostic tool to define the number of root canals and depend of full access of root canals. Difficulties during compared findings with the analysis of images obtained the root canal preparation are responsible for the lack of by using digital radiographs with charged coupled devices information of internal dental anatomy (1). (CCD) and photostimulable phosphor plates (PSP). Seventy- The anatomic structures of human teeth (number of two extracted teeth (maxillary molars, mandibular premolars roots, root canals, apical foramina, root canal isthmuses, and mandibular incisors) were evaluated using CCD, PSP and root ramifications, root curvatures, developmental CBCT scans. Three board-certified endodontists evaluated disturbances), which constitute its micromorphology CCD and PSP images to determine the number of root have been evaluated by destructive and non-destructive canals. CBCT images were used to establish a parameter methodologies (1-7). Among the methods described in for the comparisons. When using CCD, the number of root the literature include decalcification, radiography, vertical canals was correctly identified in 80%, 78%, and 77% of the and cross-sectional cutting, histological evaluation, cases when compared with CBCT, whereas when using PSP, stereomicroscopy analysis, surgical microscopy, plastic the number of root canals was correctly identified in 81%, casts, scanning electronic microscopy, cone beam computed 76%, and 84% of the cases, when compared with CBCT. tomography (CBCT) and micro-computed tomography Baratto-Filho et al. (11) compared the internal anatomy of (MCT) (2-11). maxillary first molars using extracted teeth, clinical factors Periapical radiography (PR) represents a method to and CBCT analysis. Microscopy and CBCT are important study the root canal anatomy most used in research and tools that may be used to locate and identify root canals. clinical Endodontics. However, the real multi-dimensional Clinical implications of knowledge of root canal of teeth structures viewed in only two dimensions leaves anatomy have been related with the successful treatment vulnerable this method featuring an important limitation obtaining full access to tooth internal areas during the Braz Dent J 26(5) 2015 sanitization process and root canal filling. Thus, based on in the mesiobuccal root and was followed by analysis of the lack of studies using tridimensional imaging methods distobuccal and palatal roots; in mandibular molars, the (with non-destructive features) to evaluate the human axial navigation started in the mesial root, followed by permanent teeth new directions of investigations must analysis of the distal root. When there were bifurcated be required. The aim of this study was to evaluate the roots, the axial navigation was concomitant in these two number of roots, root canals, and apical foramina in human roots. All CBCT images were assessed by two examiners (one permanent teeth in a subpopulation of Brazil´s Center by endodontist and one radiologist, both with 10 or more years using CBCT images. of experience), calibrated by assessing 10% of the sample. When differences were found, a consensus was reached Material and Methods by discussing results with a third examiner. Statistical data were analyzed including frequency distribution and Sample cross-tabulation. The CBCT databases selected in the present study was used previously to evaluate the frequency of root canal Results isthmuses in human permanent teeth (1). CBCT images of Table 1 shows the distribution of roots, root canals and 1,400 human teeth (618 white patients; 224 men; mean age apical foramina in all groups of human permanent teeth. of 43.4 years) was selected from January 2012 to August In maxillary first molars, three roots were found in 93% of 2014, who were referred to the dental radiology service the cases, two in 6% and one root in only 1% of the cases. due to different diagnoses. In maxillary second molars, three roots were observed in The cases included in the study were teeth without RCT, 69% of the cases, two roots in 29%, and only two teeth post or crowns; root canal with absence of calcification, had one root. Root fusions were found in several cases. internal or external root resorption, fully formed apex, The highest frequency of four root canals and four absence of orthodontic treatment, developmental disorders apical foramina was found in maxillary first molars (76%, and no pathologies. The study design was approved by 33%, respectively), followed by maxillary second molars Institutional Ethics Committee (#7968214.8.0000.5083). (41%, 25%, respectively). Two root canals were found in the mesiobuccal roots of these teeth. Imaging Method Maxillary first and second premolars had two roots in The specifications of acquire of the images used in this 66% and 17% of the cases, respectively, and one root in study were the same used in previous study (1,6). CBCT 32% and 83% of the cases, respectively. As much as 88% images were obtained using a PreXion 3D Inc. (San Mateo, of maxillary first premolars and 73% of maxillary second Root canal anatomy in CBCT images CA); thickness: 0.100 mm; dimensions: 1.170 mm x 1.570 premolars had two root canals. Six percent of maxillary mm x 1.925 mm; FOV: 56.00 mm; voxel: 0.100 mm, 33.5 s first premolars presented three root canals. (1,024 views). Tube voltage was 90 kVp, and tube current Mandibular first and second molars had two roots was 4 mA. Exposure time was 33.5 s. Images were examined in 95% and 91%, of the cases, respectively. The highest using the scanner’s proprietary software PreXion 3D Viewer frequency of four root canals and four apical foramina was (TeraRecon Inc, Foster City, CA) in a PC workstation with found in mandibular first molars (51%, 15%, respectively) Intel Core 2 Duo-6300 processor, 1.86 Ghz (Intel Corp., Santa while in mandibular second molars this frequency was 4% Clara, CA), NVIDIA GeForce 6200 turbo cache videocard and 1%, respectively. Mandibular second molars had three (NVIDIA Corporation, Santa Clara, CA), EIZO-Flexscan S2000 root canals in 87% of the cases. monitor at a resolution of 1600X1200 pixels (EIZO NANAO Mandibular first premolars had two root canals and two Corp., Hakusan, Japan), running Windows XP professional apical foramina in 29% and 20% of the cases, respectively. SP-2 (Microsoft Corp., Redmond, WA). All mandibular second premolars presented one root and 97% of them presented one root canal. In mandibular Determination of Roots, Root Canals and Apical central and lateral incisors and canines, two root canals Foramina were identified in 35%, 42% and 22% of the sample. The frequency of number of roots, root canals and apical This map-reading technique in CBCT images provided foramina in all teeth was evaluated by preview of the planes valuable information for a better visualization and sagittal, axial, and coronal. Navigation in axial slices of 0.1 identification of frequency and position of roots, root mm/0.1 mm followed the coronal to apical direction, as canals and apical foramina (Figs. 1-3). well as the apical to coronal direction. In the teeth with three or more roots, axial navigation was personalized for Discussion each root.