A Study of the Root Canal Morphology of Mandibular Anterior Teeth Using Cone-beam Computed Tomography in a Chinese Subpopulation

IntroductionThe purpose of this study was to investigate the root canal configuration of the mandibular anterior teeth using cone-beam computed tomographic (CBCT) imaging in a Chinese subpopulation.MethodsA total of 3,871 CBCT images of mandibular anterior teeth were collected from 648 patients who accepted CBCT projection as a preoperative assessment for implants or orthodontic treatment. The following items were recorded and evaluated: tooth position, root number, canal number, root canal type, the distance between the anatomic apex and the point at which the canal divided into 2 for mandibular anterior teeth with 2 root canals (excluding canines with 2 roots), and the distance between the 2 root canal orifices. The Fisher exact test was used to analyze the correlation between the number of root canals and tooth position.ResultsAll of the incisors in this study had 1 root, and 1.32% of the canines had 2 roots. The prevalence of 2 root canals in the lateral incisors (354, 27.36%) was higher than that in the central incisors (202, 15.71%) (P < .05) and the canines (81, 6.27%) (P < .05).ConclusionsThere is a high prevalence of 2 root canals in the mandibular anterior teeth of the studied Chinese subpopulation. This study provides detailed information about the root canal morphology of mandibular anterior teeth in a Chinese subpopulation.     

Proximity of Premolar Roots to Maxillary Sinus: A Radiographic Survey Using Cone-beam Computed Tomography

Introduction

The proximity of the roots of the posterior maxillary teeth to the maxillary sinus is a constant challenge to the dental practitioner. Because the majority of studies have assessed the relationship regarding molars, the present study focused on premolars.

Methods

Cone-beam computed tomographic images of 192 patients were reconstructed in sagittal, coronal, and axial planes to quantify the distances between the root apices of the maxillary premolars and the adjacent maxillary sinus. Measurements were taken for each root, and data were correlated with age, sex, side, and presence of both or absence of 1 of the 2 premolars.

Results

A total of 296 teeth (177 first and 119 second premolars) were evaluated. The mean distances from buccal roots of the first premolars to the border of the maxillary sinus in the sagittal, coronal, and axial planes ranged from 5.15 ± 2.99 to 8.28 ± 6.27 mm. From palatal roots, the mean distances ranged from 4.20 ± 3.69 to 7.17 ± 6.14 mm. The mean distances of second premolars were markedly shorter in buccal roots between 2.32 ± 2.19 and 3.28 ± 3.17 mm and in palatal roots between 2.68 ± 3.58 and 3.80 ± 3.71 mm, respectively. The frequency of a premolar root protrusion into the maxillary sinus was very low in first premolars (0%–7.2%) but higher in second premolars (2.5%–13.6%). Sex, age, side, and presence/absence of premolars failed to significantly influence the mean distances between premolar roots and the maxillary sinus.

Conclusions

Based on the calculated mean distances of the present study, only few premolars (and if so second premolars) would present a risk of violating the border of the maxillary sinus during conventional or surgical endodontic treatment or in case of tooth extraction.     

锥体束CT对上颌第一磨牙近中颊根管形态的研究

目的：通过锥体束CT（cone--beam computed tomography,CBCT）成像系统分析上颌第一磨牙近中颊根根管形态及第二（second mesiobuccal,MB2）根管的发生率。方法：选择95名进行CBCT扫描的患者,共计180颗上颌第一磨牙,观察近颊根根管形态、MB2根管的发生率、左右侧发生比率及男女发生比率差异。结果：上颌第一磨牙近颊根管形态以Ⅲ型为主,MB2根管发生率为79．4％,左右侧发生比率无统计学差异（P=0．846）,男性发生率明显高于女性（P=0．043）。结论：上颌第一磨牙近颊根MB2根管的发生率较高,可通过CBCT有效的发现MB2根管,为临床诊疗提供依据。     

锥体束CT对维吾尔族成人下颌第二磨牙C形根管的研究

目的: 通过锥体束CT(cone-beam computed tomogphy,CBCT)成像系统对新疆维吾尔族成人下颌第二磨牙C形根管的发生率及其形态特征进行研究。方法: 选择来我院体检且下颌牙列完整的100名维吾尔族成人,进行CBCT扫描,观察下颌第二磨牙的根管形态。结果: C形根管的发生率为15.0%,C 形根管类型变化多样。结论: C形根管在下颌第二磨牙有较高的发生率,且解剖形态存在较大差异。CBCT在C形根管的诊断方面具有重要作用,可以为维吾尔族成人下颌第二磨牙C形根管的临床诊疗提供依据。     

Assessment of Perceptions of Cone-beam Computed Tomography and Endodontic Treatment in a Military Population

IntroductionCone-beam computed tomographic (CBCT) imaging has had a significant impact in endodontic diagnosis and treatment planning. Previous studies have investigated provider attitudes and the use of CBCT technology, but little is known about patients’ perceptions of the use of CBCT imaging in endodontics. This study assessed the perceptions of patients within a military population regarding the application of CBCT imaging for endodontic treatment.MethodsOne hundred three consecutive, volunteer patients who were treated in a military dental treatment facility and prescribed a CBCT study according to the American Association of Endodontists/American Academy of Oral and Maxillofacial Radiology guidelines were given a Likert-type survey that recorded an initial level of knowledge and attitudes regarding the use of CBCT in endodontics. After standardized patient education in the form of a 2-minute video presentation describing the applications and risks associated with CBCT technology, CBCT volumes were acquired. A second survey was administered to record the patients’ perceptions of the benefits and risks associated with CBCT imaging.ResultsAfter the video, 75% of the participants had a more positive opinion of CBCT technology; 56% felt that CBCT imaging was essential, and 44% felt it was beneficial. Fifty percent of the participants reported CBCT imaging having less radiation than they previously thought, whereas 11% thought it was more radiation. A total of 85% would seek out a provider who uses CBCT imaging if treatment is needed in the future.ConclusionsWhen presented with basic information, most patients within a military population perceive CBCT imaging to have an important role in endodontic treatment.     

Cone-Beam Computed Tomography Detection of Separated Endodontic Instruments

IntroductionThis study compared the accuracy, sensitivity, and specificity of different imaging diagnostic protocols, cone-beam computed tomography (CBCT) and digital periapical radiography (DPR), in identifying separated endodontic instruments in filled root canals.MethodsOne hundred eight root canals from 36 mandibular molars were prepared and obturated. Of these, 84 were filled without separated instruments, and 24 were filled with the presence of a separated instrument (stainless steel hand file or reciprocating instrument). Subsequently, different CBCT imaging protocols were acquired: i-CAT Classic (ICC) (0.25-mm isotropic voxel), i-CAT Next Generation (ICN) (0.125-mm isotropic voxel), and PreXion 3D (PXD) (0.09-mm isotropic voxel). Moreover, a DPR exam was obtained (08 mA, 70 kVp, and exposure time of 0.2 seconds). Two calibrated endodontists evaluated each image for the presence or absence of fractured files on a 5-point scale, ranging from definitely absent to definitely present. The accuracy, sensitivity, and specificity measures for each method were estimated. The data were evaluated by Fisher exact test and binomial test.ResultsNine instruments were identified in DPR (37.5%) and none in the CBCT protocols (P > .05). The type of instrument (stainless steel hand file or reciprocating instrument) did not influence the identification of the separated instrument (P > .05). This study showed that DPR is the most accurate and sensitive imaging technique, with 83.3% and 37.5%, respectively.ConclusionsDPR is the better imaging diagnostic exam to evaluate the presence of separated endodontic instruments inside a root canal in comparison with the ICC, ICN, and PXD tomographic protocols. However, most of the separated instruments were not identified.     

Cone-beam Computed Tomography Compared with Intraoral Radiographic Lesions in Endodontic Outcome Studies: A Systematic Review

Introduction

The purpose of this systematic review was to compare and quantify endodontic outcome using cone-beam computed tomographic (CBCT) imaging with intraoral periapical radiography.

上颌第一、第二恒磨牙牙根和根管系统的锥形束CT研究

目的：运用锥形束CT（CBCT）观察中国人群双侧上颌第一、第二磨牙的牙根和根管系统的解剖形态,为临床根管治疗提供依据。方法：选择200名患者的双侧上颌第一、第二恒磨牙（上颌第一恒磨牙354颗、上颌第二恒磨牙360颗）的CBCT扫描数据,使用NNT软件分析上颌第一、第二恒磨牙的牙根数、根管数、根管分型以及双侧对称情况。结果：上颌第一、第二磨牙主要为三根（99.44%和84.44%）。上颌第二磨牙的单根和双根较多见（15.28%）,其根管系统形态复杂,在根尖区有融合趋势。上颌第一磨牙的根管系统主要为3根四根管（78.97%）。上颌第二磨牙的三根管和四根管发现率接近（分别为47.37%和51.64%）。上颌第一磨牙的近颊根管系统主要根管分型为：Ⅳ型（57.79%）、Ⅱ型（19.83%）和Ⅰ型（15.58%）。上颌第二磨牙的近颊根管系统主要根管分型为：Ⅰ型（48.14%）、Ⅳ型（30.43%）和Ⅱ型（17.39%）。上颌第一、第二磨牙的远颊根和腭根主要为单根单根管,存在少量和罕见的变异。上颌第一、第二磨牙近颊根的根管数目和根管分型左右对称。结论：上颌第一磨牙近颊根管系统变异普遍存在,MB2根管为其主要的变异形式。上颌第二磨牙牙根数目和根管形态变异类型多,单根牙和双根牙的根管走向复杂多变。CBCT可以为识别根管形态提供准确依据。     

Four-year Outcome of Nonsurgical Root Canal Retreatment Using Cone-beam Computed Tomography: A Prospective Cohort Study

IntroductionThe purpose of this prospective study was to investigate the 4-year outcome and prognostic factors of nonsurgical root canal retreatment determined by measuring the volumetric change of periapical radiolucencies on cone-beam computed tomographic (CBCT) scans.MethodsNinety-seven endodontically treated teeth from 80 patients diagnosed as apical periodontitis and indicated for root canal retreatment were included. Retreatment was performed by 7 endodontic specialists using a standardized treatment protocol. The teeth were reexamined clinically and radiographically 48–67 months after retreatment. The volume of preoperative and postoperative periapical radiolucencies on CBCT images was independently measured by 2 examiners. Radiographic outcome is presented in 4 categories: absence, reduction, enlargement, or unchanged. Reduction or enlargement was determined when the volumetric change of radiolucency was 20% or more. Multivariate logistic regression was performed for predictor analysis.ResultsSixty-two teeth (63.9%) from 50 patients returned for follow-up. Fifty-eight teeth were included in the prognostic analysis, all of which were symptom free. The 4 remaining teeth that had been extracted because of fracture were excluded. The total volume of periapical radiolucencies at 4 years postoperatively decreased by 94.6% compared with that preoperatively (P < .001), with an average reduction of 83.4% (95% confidence interval, 69.2%–97.5%). The periapical radiolucencies were determined as absence in 44 teeth (75.9%), reduction in 10 teeth (17.2%), unchanged in 1 tooth (1.7%), and enlargement in 3 teeth (5.2%). Tooth type was identified as an outcome predictor (P < .05).ConclusionsThe 4-year outcome of endodontic retreatment is predictable, with a significant volumetric reduction in periapical radiolucencies.     

In Vivo Detection of Subtle Vertical Root Fracture in Endodontically Treated Teeth by Cone-beam Computed Tomography

IntroductionThe purpose of this study was to evaluate the diagnostic accuracy of cone-beam computed tomographic (CBCT) imaging in the detection of subtle vertical root fractures (VRFs) in endodontically treated teeth in vivo and to discuss direct and indirect evidence for the diagnosis of subtle VRFs.MethodsTwenty-nine endodontically treated teeth with suspected VRFs from 29 patients were examined using CBCT imaging. CBCT images were scored based on evaluation of the fracture line and vertical buccopalatal (lingual) bone loss. VRF was diagnosed only when a definite fracture line was detected on CBCT images, and findings of periodontal exploration or surgical extraction were considered the gold standard. The diagnostic sensitivity, specificity, and accuracy were assessed.ResultsOf the 29 teeth, 27 were positive and 2 were negative for VRF according to the gold standard. Sensitivity, specificity, and accuracy were 33.3%, 100%, and 37.9%, respectively, based on the direct finding of a fracture line on CBCT images. However, vertical buccopalatal (lingual) bone loss was found in 25 of 27 teeth with VRFs.ConclusionsAlthough the accuracy of CBCT imaging for the diagnosis of subtle VRFs in endodontically treated teeth in vivo was poor, vertical buccopalatal (lingual) bone loss is an important indirect sign for the diagnosis of VRFs, which can be found on CBCT images.     

The Incidence of Second Mesiobuccal Canals Located in Maxillary Molars with the Aid of Cone-beam Computed Tomography

Introduction

Many endodontic treatment failures in maxillary molars result from missed second mesiobuccal (MB2) canals. An MB2 canal orifice is present in as many as 95% of maxillary molars, but these canals are not always located during endodontic procedures. Additional tools, such as cone-beam computed tomographic (CBCT) imaging, may be needed to locate these canals in maxillary molars. Hence, the aims of this study were to investigate the frequency of use of CBCT imaging during the treatment of maxillary molars and to evaluate the influence of its use on the detection of MB2 canals.

Interobserver and Intraobserver Reliability of Cone-beam Computed Tomography in Identification of Apical Periodontitis

Introduction

Accurate radiographic interpretation is of the utmost importance in the diagnosis and treatment of patients. Previous studies have indicated subjectivity in the radiographic interpretation of periapical tissues irrespective of using conventional radiography, digital radiography, or cone-beam computed tomographic (CBCT) imaging. No studies to date have evaluated the reliability of the interpretation of periapical tissues based on the size of periapical radiolucency (PAR). The purpose of this study was to assess the interobserver and intraobserver reliability of CBCT interpretation by observers from different specialties and different levels of experience when identifying PARs of various sizes.

The Importance of Cone-beam Computed Tomography in the Management of Endodontic Problems: A Review of the Literature

Introduction

To obtain essential information in clinical endodontics, cone-beam computed tomographic (CBCT) imaging can be used in all phases of treatment including diagnosis, treatment planning, during the treatment phase, and through post-treatment assessment and follow-up. The purpose of this article was to review the use of CBCT imaging in the diagnosis, treatment planning, and assessing the outcome of endodontic complications.

Methods

Literature was selected through a search of PubMed electronic databases for the following keywords: tooth root injuries, tooth root radiography, tooth root perforation, tomography, cone-beam computed tomography, endodontic complications, tooth root internal/external resorption, root fractures, and broken instruments. The research was restricted to articles published in English. One hundred twelve articles met the inclusion criteria and were included in this review.

Results

Currently, intraoral radiography is the imaging technique of choice for the management of endodontic disease, but CBCT imaging appears to have a superior validity and reliability in the management of endodontic diagnosis and complications.

Conclusions

Endodontic cases should be judged individually, and CBCT imaging should be considered in situations in which information from conventional imaging systems may not yield an adequate amount of information to allow the appropriate management of endodontic problems. CBCT imaging has the potential to become the first choice for endodontic treatment planning and outcome assessment, especially when new scanners with lower radiation doses will be available.     

Periapical and Endodontic Status Scale for Endodontically Treated Teeth and Their Association with Maxillary Sinus Abnormalities: A Cone-beam Computed Tomographic Study

IntroductionThis retrospective cross-sectional study investigated the applicability of the periapical and endodontic status scale (PESS) to determine the association of endodontically treated teeth with maxillary sinus (MS) abnormalities through cone-beam computed tomographic imaging.MethodsA total of 631 endodontically treated teeth were analyzed. MS abnormalities were classified as mucosal thickening, sinus polyp, antral pseudocyst, nonspecific opacification, periostitis, and antral calcification. The PESS was used to evaluate the quality of endodontic treatment as well as periapical tissue conditions. The data were analyzed by chi-square tests (P < .05).ResultsMS abnormalities were detected in 70.52% of the sample, with a greater prevalence of mucosal thickening (38.19%), whereas periapical lesions were observed in 55.94% of the cases. Treated root canals with unsatisfactory filling, homogeneity, and coronal sealing had an odds Ratio (OR) of 2.21, 2.88, and 2.99, respectively (P < .001). Periapical lesions larger than 5 mm (OR = 314.95), in more than 1 root (OR = 3.72), involving the furcation region (OR = 5.21), in contact with important structures (OR = 7.37), and with cortical bone destruction (OR = 4.09) were significantly related to the presence of MS abnormalities (P < .001). An OR of 99,668 was observed in periostitis lesions greater than 5 mm (P < .001).ConclusionsThe PESS proved to be an important tool for the analysis of endodontic and periapical conditions and was applicable to determine potential associations with MS abnormalities.     

Morphology of Mandibular First Molars Analyzed by Cone-beam Computed Tomography in a Korean Population: Variations in the Number of Roots and Canals

Introduction

The aim of this study was to determine the root and canal morphology of the mandibular first molars in a Korean population of Mongolian origin by retrospective analysis of a large number of cone-beam computed tomography (CBCT) images.

Methods

A total of 976 subjects with bilateral mandibular first molars were examined by using in vivo CBCT methods. The number and configuration of roots, the number of root canals, and the canal configuration based on Vertucci's classification were determined.

Results

Overall, 25.82% of examined molars had 3 roots, 73.51% had 2 roots, and 0.67% had 1 root. The incidence of fourth canal was 50.36%. A right-sided predominance was noted for extra distal roots (P < .001), whereas a left-sided predominance was observed for extra distal canals (P < .001). No significant sex-related differences were shown for their prevalence. The bilateral prevalence rate was 69.13% for extra distal roots and 78.08% for extra distolingual (DL) canals. In the mesial roots, type IV canal was the most frequent (76.86% for 2-rooted molars and 72.96% for 3-rooted molars). In the distal roots, type l was the most common (66.62% for 2-rooted molars and 99.40%–100% for 3-rooted molars). The incidence of 2 canals in distobuccal roots, first reported in this study, was 0.15%.

Conclusions

Among mandibular first molars, there is a high prevalence of a separate DL root and/or a separate DL canal, and such molars commonly have 4 canals in the Korean population. CBCT is a useful tool for determining root and canal morphology.     

Evaluation of 10 Cone-beam Computed Tomographic Devices for Endodontic Assessment of Fine Anatomic Structures

IntroductionThe purpose of this study was to classify 10 cone-beam computed tomographic (CBCT) devices using a ranking model according to the detection of fine endodontic structures.MethodsA dedicated dentate anthropomorphic phantom was scanned 2 times using 10 CBCT devices without any metal (metal-free condition) and with an endodontically treated tooth containing a metallic post (metal condition). A reference image acquired on an industrial micro-CT scanner was used to register all CBCT images, yielding corresponding anatomic slices. Afterward, 3 experienced observers assessed all acquired CBCT images for their ability to assess a narrow canal, isthmus, and apical delta ramification using a categoric rank from 1 (best) to 10 (worst). Fleiss kappa statistics were used to calculate intra- and interobserver agreements for each CBCT device separately. Based on the observers’ scores, general linear mixed models were applied to compare image quality among different CBCT devices for performing endodontic diagnostic tasks (α = .05).ResultsThe 10 CBCT devices performed differently for the evaluated endodontic tasks (P < .05), with 3 devices performing better for endodontic feature detection. Yet, in the presence of metal, only 2 devices were able to keep a high level of endodontic feature detection.ConclusionsThe evaluated endodontic tasks were CBCT device dependent, and their detection was influenced by the presence of metal.     

Volumetric Pulp Changes after Orthodontic Treatment Determined by Cone-beam Computed Tomography

Introduction

The purpose of this study was to observe and evaluate 3-dimensional pulp cavity changes during orthodontic treatment.

Methods

Eighty-seven patients formed the study sample and were divided into an experimental group (48 patients) and a control group (39 patients). Cone-beam computed tomographic (CBCT) records were obtained before the start of the treatment (T0) and after space closure for the experimental group, whereas for the control group CBCT images were obtained approximately 17–18 months (T1) after obtaining the first image (T0). CBCT data were reconstructed with surface and volume rendering software (Mimics; Materialise, Leuven, Belgium), and the volumetric images were modified to display the teeth from various orientations. Six anterior teeth were segmented and their pulps isolated. Paired t test was used to check for statistical significance.

Results

The difference in the pulp volume was statistically significant at P < .05 for all the anterior teeth in the experimental group and at P < .05 for the right canine, P < .05 for the right and left lateral incisors, and P < .05 for the left central in the control group.

Conclusions

Orthodontic treatment in the experimental group produced a significant decrease in the size of the pulp, which was statistically significant.     

CBCT与RVG对下颌恒切牙根管形态评估的对比研究

目的:对比CBCT法与数字化X线成像法(RVG)对下颌恒切牙根管形态评估的差异。方法:对101颗离体牙进行唇舌向及近远中向数字化X线片拍摄和CBCT高清牙列模式扫描,对图像进行根管数目、Vertucci根管分型、根管钙化和根尖口开口位置的评估,并通过CBCT图像建立偏角度投照的三角函数模型,计算偏向投照的角度。结果:CBCT法显示有30颗为双根管,RVG近远中向投照显示有36颗为双根管,卡方检验显示对根管数目和Vertucci根管分型两种方法均具有显著性差异(P<0.05)。两种方法对根管钙化和根尖口开口位置的评估均不具有显著性差异。30颗双根管牙中下颌恒切牙唇舌向双根管的最大距离(LaL)在0~1.5 mm之间的,85.7%的为Vertucci III型,LaL在1.5~2 mm之间的,66.7%为Vertucci IV和V型。以根尖片上双根管显示距离为1 mm计算,LaL在1~2 mm之间的,偏向投照角度为26.6°~45.0°,LaL在0.1~1 mm之间的,偏向投照角度为45.0°~84.3°。结论:CBCT高清牙列模式扫描和RVG投照对于根管数目和Vertucci根管分型的评估具有显著性差异,对于根管钙化和根尖口开口位置的评估不具有显著性差异。LaL在1~2 mm之间时,偏角度投照的临床可操作性较强。     

Complicated Root Canal Morphology of Mandibular Lateral Incisors Is Associated with the Presence of Distolingual Root in Mandibular First Molars: A Cone-beam Computed Tomographic Study in a Taiwanese Population

Introduction

The aim of this study was to assess the root canal configurations in permanent mandibular lateral incisors (PMLIs) and the correlation between the root canal configurations of PMLIs with the appearance of a distolingual root (DLR) in permanent mandibular first molars (PMFMs) using cone-beam computed tomographic (CBCT) imaging.

The Presence of Distolingual Root in Mandibular First Molars Is Correlated with Complicated Root Canal Morphology of Mandibular Central Incisors: A Cone-beam Computed Tomographic Study in a Taiwanese Population

Introduction

The aim of this study was to assess the prevalence of complicated root canals in permanent mandibular central incisors (PMCIs) and its correlation with the presence of a distolingual root (DLR) in permanent mandibular first molars (PMFMs) using cone-beam computed tomographic imaging in a Taiwanese population.