Analysis of the Width of Vertical Root Fracture in Endodontically Treated Teeth by 2 Micro–Computed Tomography Systems

Introduction

Early detection of vertical root fracture (VRF) is important for clinical endodontic practice. The purpose of this study was to measure the fracture width (distance between 2 sides of the fracture) of VRF teeth in vitro by using 2 micro–computed tomography (μ-CT) systems with different spatial resolution and voxel size.

Methods

Thirty-seven endodontically treated teeth with VRF were scanned by 80-μm pixel size μ-CT. Fifteen teeth with no obvious fracture line, blurred image, or fracture space less than 100 μm were scanned by 9-μm pixel size μ-CT.

Results

Presence of 2 VRF lines was more common in premolars (82%) than in molars (53%). In 7 premolars (32%) and 9 molars (60%), the VRF lines extended to within the apical 3 mm of the root. All fracture lines were detected by 9-μm pixel size μ-CT, but only 22 of 37 VRF teeth had vertical fracture identified by 80-μm μ-CT. From μ-CT examination, none of the fracture lines showed consistent and uniform fracture space. If 2 fracture lines were present, they were typically in opposite (not linear) directions. There was a significant correlation between 2 fracture lines or fracture lines extending within the 3 mm of the apex and fracture width greater than 100 μm.

Conclusions

Application of 9-μm μ-CT can be accurately used for early detection of VRF. Fracture characteristics (eg, number of fracture lines, extension of fracture line) may affect the fracture width. Appropriate use of μ-CT technology can be helpful for early diagnosis of VRF.     

Incidence of Middle Mesial Canals Based on Distance between Mesial Canal Orifices in Mandibular Molars: A Clinical and Cone-beam Computed Tomographic Analysis

IntroductionThis study evaluated the presence of midmesial canals (MMCs) in a random sample of mandibular molars and the relationship of the intracanal distance between mesiobuccal (MB) and mesiolingual (ML) canal orifices.MethodsFifty-one extracted mandibular molars were divided into samples of 3 to 4 teeth, mounted in plaster and boxing wax, and immersed in water before cone-beam computed tomographic (CBCT) imaging. Two endodontic residents completed the access openings. The teeth and the CBCT images were interpreted for the presence of MMCs and the mesial intracanal distance. CBCT software measured the distance between the buccal of the MB canal to the lingual of the ML canal at the pulpal floor to determine the average length between the canals.ResultsSeven distinct MMCs were seen both clinically (incidence of 13.725%) and on the CBCT images. Twenty-seven teeth (52.94%) had ambiguous broad isthmi between the MB and the ML orifices. MMCs were present at the furcation level but merged with the MB or ML canal toward the apex in 6 of 7 teeth (85.71%). The mean distance between the mesial canals in teeth with MMCs was 3.643 mm, and it was 3.818 mm for teeth without MMCs. According to independent sample t testing, the P value was >.05.ConclusionsThe incidence of MMCs in mandibular molars appears consistent with the literature. However, there does not appear to be a statistically significant difference in the mesial intracanal distance in teeth with and without MMCs. Visualization of MMCs on CBCTs may be subjective. There does not appear to be a correlation between the presence of MMCs and an increased or decreased mesial intracanal distance.     

Accuracy of Different Imaging CBCT Systems for the Detection of Natural External Radicular Resorption Cavities: An Ex Vivo Study

ObjectiveThe aim of this study was to compare the sensitivity and specificity of 3 different systems of cone-beam computed tomography (CBCT) in the detection of natural external root resorption (ERR) cavities using microtomography as the gold standard.MethodA sample of 126 ex vivo teeth were submitted to a microtomography examination to verify the presence/absence of ERR cavities. Then, they were divided into the control group: 85 teeth that did not present with an ERR cavity; and experimental group: 41 teeth that presented with 1 or more ERR cavities. The size of the natural ERR cavities varied from 2.46 mm³ to 3.11 mm³, which corresponded to cavities of 1.67 mm and 1.81 mm in diameter, respectively. The teeth were placed on a dry human mandible for scanning in each of the 3 protocols with different voxel sizes: 0.25 mm, 0.20 mm, and 0.166 mm.ResultsThe accuracy of the 3 protocols evaluated in this study are listed in decreasing order: 60.3% for a voxel size of 0.20 mm, 56.7% for a voxel size of 0.166 mm, and 46.7% for a voxel size of 0.25 mm; these are smaller values than previous studies have obtained using artificial ERR cavities. Statistically significant results were not found among the 3 CBCT protocols that were used (P > .05), and the receiver operating characteristic curve shows the small differences found between the protocols.ConclusionThe results indicate that CBCT presents, for natural ERR, lower sensitivity and specificity values than those detected in previous studies of artificial cavities. The results demonstrate that natural ERR is neither easily observed nor accurately located by CBCT, as previous studies using artificial ERR indicated.     

Evaluation of anatomic variations of mandibular lingual concavities from cone beam computed tomography scans in a Malaysian population

Statement of problemLingual plate perforation can be life-threatening when vital structures are damaged during implant placement. Knowledge of the anatomy of lingual concavities is imperative for safe implant surgery.PurposeThe purpose of this clinical study was to determine the prevalence of type of posterior mandibular ridge morphology in a Malaysian population and to evaluate the buccolingual width of the alveolar ridge (Wb and Wc); alveolar ridge height (Vcb); and concavity angle, length, and depth for both left and right first and second molars in different age groups and sexes by using cone beam computed tomography (CBCT).Material and methodsBilateral posterior mandibular lingual concavities at the first and second molars were retrospectively studied in cross-sectional views of 150 CBCT scans (n=600 sites evaluated). The sample size was calculated at a power of 80%, confidence interval of 95%, and margin of error of .05. The buccolingual width from the base and crest of the ridge and the ridge height were measured to determine the type of ridge. For the U-shaped ridge, the concavity angle, length, and depth were assessed. The independent t test was used to compare mean values of CBCT measurements between sexes and tooth type, while the ANOVA and Pearson chi-squared test were used to determine the correlations with age groups and types of ridge morphology, respectively. To compare the left and right readings for first and second molars in the same patient, the paired t test was performed (α=.05 for all tests).ResultsThe Pearson correlation showed a strong agreement between the 2 examiners with an interobserver reliability of 87.3%. Significant difference was noted in all dimensional measurements when comparing right and left first and second molars (P<.001). The degree of concavity was significantly different (P<.05), except for the depth of the concavity at the left molars (P=.075). The type C ridge (51.7%) was the most prevalent ridge among a Malaysian population. Only dimensional measurements were significantly different when compared among age groups (P<.05). Ridge width and height were significantly greater in men (P<.05). Men exhibited greater concavity depth than women in the left second molar region (P=.03).ConclusionsLingual concavity was found in the mandible in 32.8% of a Malaysian population. Significant differences were found in dimensional measurements and degree of concavity between left and right first and second molars, with deeper concavity depth found in second molars. Significant age and sex-related variations were found in the dimensional measurements of the mandible between left and right sides with no significant difference in degree of concavity.     

Comparison of the Accuracy of 3-dimensional Cone-beam Computed Tomography and Micro–Computed Tomography Reconstructions by Using Different Voxel Sizes

Introduction

Cone-beam computed tomography (CBCT) data are, in principle, metrically exact. However, clinicians need to consider the precision of measurements of dental morphology as well as other hard tissue structures. CBCT spatial resolution, and thus image reconstruction quality, is restricted by the acquisition voxel size. The aim of this study was to assess geometric discrepancies among 3-dimensional CBCT reconstructions relative to the micro-CT reference.

Methods

A total of 37 permanent teeth from 9 mandibles were scanned with CBCT 9500 and 9000 3D and micro-CT. After semiautomatic segmentation, reconstructions were obtained from CBCT acquisitions (voxel sizes 76, 200, and 300 μm) and from micro-CT (voxel size 41 μm). All reconstructions were positioned in the same plane by image registration. The topography of the geometric discrepancies was displayed by using a color map allowing the maximum differences to be located.

Results

The maximum differences were mainly found at the cervical margins and on the cusp tips or incisal edges. Geometric reconstruction discrepancies were significant at 300-μm resolution (P = .01, Wilcoxon test).

Conclusions

To study hard tissue morphology, CBCT acquisitions require voxel sizes smaller than 300 μm. This experimental study will have to be complemented by studies in vivo that consider the conditions of clinical practice.     

Effect of Field of View and Voxel Size on CBCT-Based Accuracy of Dynamic Navigation in Endodontic Microsurgery: An In Vitro Study

IntroductionThis study aimed to evaluate the influence of field of view (FOV) and voxel size on the accuracy of dynamic navigation (DN)–assisted endodontic microsurgery (EMS).MethodsNine sets of maxillary and mandibular 3-dimensional–printed jaw models composed of 180 teeth were divided into 9 groups with different FOVs (80 × 80 mm, 60 × 60 mm, and 40 × 40 mm) and voxel sizes (0.3 mm, 0.16 mm, and 0.08 mm). The endodontic DN system was used to plan and execute the EMS. The accuracy of the DN-EMS was represented by the platform deviation, end deviation, angular deviation, resection angle, and resection length deviation. Statistical analyses were performed using SPSS 24.0, and the significance level was set at P < .05.ResultsThe average platform deviation, end deviation, angular deviation, resection angle, and resection length deviation were 0.69 ± 0.31 mm, 0.93 ± 0.44 mm, 3.47 ± 1.80°, 2.35 ± 1.76°, and 0.41 ± 0.29 mm, respectively. No statistically significant differences in accuracy were observed between the nine FOV and voxel size groups.ConclusionsFOV and voxel size did not appear to play an important role in the accuracy of DN-EMS. Considering the image quality and radiation dose, it is reasonable to select a limited FOV (such as 40 × 40 mm and 60 × 60 mm) to cover only the registration device, involved teeth, and periapical lesion. The voxel size should be selected according to the required resolution and cone-beam computed tomography units.     

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.     

Guided Access Cavity Preparation Using a New Simplified Digital Workflow

IntroductionThis study evaluated the precision of a simplified workflow using only preoperative cone-beam computed tomographic (CBCT) scans to gain guided access to root canals of extracted mandibular molars. A workflow using CBCT scanning associated with 3-dimensional oral scanning was used as a reference for comparison. The influence of the presence of coronal restoration in the simplified workflow was also evaluated.MethodsForty-five mandibular molars were randomized into 3 groups: a control group in which digital planning was performed with CBCT and oral scanning and 2 experimental groups in which digital planning was performed only with CBCT examination. In experimental group 1, teeth had no coronal restorations, whereas in group 2 teeth presented with coronal composite restorations. After digital planning, the teeth were accessed using the guides, and a new CBCT scan was made to overlap the pre- and postoperative examinations. Precision was measured by calculating the deviation between the planned and prepared cavities in millimeters and angle. Data were compared using 1-way analysis of variance (P < .05).ResultsAll root canals were accessible after access preparation in all tested groups. Deviations of the planned and prepared access cavities were low, with a mean value of 0.55, 0.58, and 0.47 mm and 1.98°, 2.45°, and 1.43° for the control group, group 1, and group 2, respectively. No significant differences in millimeters or angle were observed among the 3 tested groups (P > .05).ConclusionsThe simplified digital workflow using only CBCT examination allowed a high level of precision in obtaining access in extracted molars with and without coronal restoration, presenting similar results compared with the digital workflow using CBCT and 3-dimensional oral scanning.     

The usefulness of cone-beam computed tomography gray values for alveolar bone linear measurements

Objectives:To test a proof-of-concept that the accuracy and reliability of alveolar bone height measurements from orthodontic grade (large field-of-view [FOV], large voxel-size) cone-beam computed tomography (CBCT) images may be improved by using pixel gray values.Materials and Methods:Twenty fresh cadaver pig heads underwent CBCT scans (17 × 23 cm FOV, 0.4-mm voxel size). Buccal alveolar bone heights of maxillary first molars were measured using the conventional vision-based (VB) and the proposed gray value–assisted (GVA) methods. The GVA methods entailed localization of landmarks through observation of gray value pattern changes across tissue boundaries followed by mathematical calculation of distances between landmark pixels. Interrater reliability and accuracy of CBCT measurements made by all methods were statistically analyzed by comparing with physical measurements (gold standards).Results:The interrater reliability of CBCT measurements made by GVA methods was comparable to physical measurements but higher than those made by the VB method. The GVA (bend-down pattern) method yielded average measurements similar to physical measurements, while those obtained by the VB and the GVA (straight pattern) methods were significantly larger (repeated measures analysis of variance, P < .001). The GVA (bend-down pattern) method also produced significantly more measurements within one voxel size of physical measurements than did the VB and GVA (straight pattern) methods (Chi-square tests, P < .017).Conclusions:These data confirm a concept that local gray value change patterns may be used to improve the accuracy and reliability of alveolar bone height measurement from large FOV and large voxel-size 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.

The MB3 canal in maxillary molars: a micro-CT study

Objectives

To assess the internal and external morphologies of the mesiobuccal (MB) root of maxillary molars presenting a third root canal (MB3), using micro-computed tomography (micro-CT).

Material and methods

Two-hundred and sixty-five extracted maxillary first and second molars with different root configurations were imaged in a micro-CT scanner at 19.6-μm pixel size. Sixteen teeth presenting MB3 canal were selected and evaluated regarding root configuration, minimal dentine thickness 2 mm under the furcation area, canal configuration of the MB root, MB3 canal morphology (location, independent or confluent orifice, and anatomy types), and the apical anatomy (aspect ratio, number of accessory canals and foramina, presence of isthmus, and independent MB3 foramen).

Results

Overall, a high variability in canal configuration was detected in the MB root. MB3 canal was observed in 10 maxillary first molars and 6 maxillary second molars (n = 16). Minimal dentine thickness related to the MB3 canal at the coronal third was smaller than that of the MB1 canal. A complex internal anatomy comprising 13 different root canal configurations was observed. A high number of independent MB3 orifices at the pulp chamber floor was observed in the first molars (7 out of 10 teeth), while most of the specimens (n = 14) showed a confluent anatomy of the MB3 canal. A varied number of accessory canals and foramina were observed. At the apical third, isthmus could be observed in 6 specimens, while an independent MB3 foramen was present in 37.5% of the MB roots.

Conclusions

MB3 canal is a rare anatomical variation present in maxillary first and second molars. Its presence can be associated to a complex internal anatomy of the MB root which includes the presence of isthmuses and multiple accessory canals and foramina at the apical third, but also a thin dentine thickness at the coronal third and a confluent anatomy of the MB3 with the other main canals.

     

Influence of the Intracanal Material and Metal Artifact Reduction Tool in the Detection of the Second Mesiobuccal Canal in Cone-beam Computed Tomographic Examinations

IntroductionThe aim of this study was to evaluate the influence of different intracanal materials and the metallic artifact reduction (MAR) tool of cone-beam computed tomographic (CBCT) imaging on the detection of the second mesiobuccal (MB2) canal in maxillary first molars.MethodsForty maxillary first molars were selected; half of them had the MB2 canal in the mesiobuccal root confirmed by micro–computed tomographic imaging. All teeth were instrumented, except for the MB2 canal, and filled with gutta-percha, which was passively inserted up to the working length. Each tooth was individually inserted into a dry human skull, and CBCT scans were performed using the OP300 device (Instrumentarium Dental, Tuusula, Finland) with and without the use of the MAR tool. For each scanned tooth, the following intracanal materials were used in the palatal root: gutta-percha, silver palladium, nickel chromium, and cobalt chromium. Five examiners assessed the images for the detection of the MB2 canal using a 5-point scale. The weighted kappa test was applied to evaluate intra- and interexaminer reproducibility. The diagnostic values (sensitivity, specificity, and area under the receiver operating characteristic curve) were calculated in the different groups and compared using 2-way analysis of variance and the Tukey post hoc test.ResultsThe intra- and interobserver agreement ranges for the different conditions were studied. The diagnostic values were not significantly different (P > .05) regardless of the intracanal material and the use of the MAR tool.ConclusionsThe presence of different intracanal materials and MAR activation does not influence CBCT-based detection of MB2 canals.     

Precision,reproducibility, and accuracy of bone crest level measurements of CBCT cross sections using different resolutions

Objective:To evaluate the precision, reproducibility, and accuracy of alveolar crest level measurements on CBCT images obtained with different voxel sizes.Materials and Methods:CBCT exams were made of 12 dried human mandibles with voxel dimensions of 0.2, 0.3, and 0.4 mm. Bone crest level was measured directly on the mandibles with a digital caliper and on CBCT images. Images were measured twice by two examiners. Intra- and interexaminer precision and reproducibility were assessed using paired and t-tests, respectively. Accuracy was evaluated using t-tests.Results:Precision and reproducibility of bone crest level tomographic measurements was good for all voxel sizes evaluated. The images with 0.2-mm voxel size showed a decreased number of intraexaminer errors. A high accuracy for measurements of bone crest level was observed for all CBCT definitions, except for the mandibular incisors using the 0.4-mm voxel size.Conclusions:Precision and reproducibility of alveolar bone level measurements were good for various voxel sizes. CBCT images demonstrated good accuracy for 0.2-mm and 0.3-mm voxel sizes. The mandibular incisor region needs better resolution than that provided by 0.4-mm voxel size for bone crest level measurements.     

Efficacy of clinical and radiological methods to identify second mesiobuccal canals in maxillary first molars

Abstract

Introduction. The success of endodontic treatment depends on the identification of all root canals. Technological advances have facilitated this process as well as the assessment of internal anatomical variations. The aim of this study was to compare the efficacy of clinical and radiological methods in locating second mesiobuccal canals (MB2) in maxillary first molars. Methods. Fifty patients referred for analysis; access and clinical analysis; cone-beam endodontic treatment of their maxillary first molars were submitted to the following assessments: analysis; access and clinical analysis; cone-beam computed tomography (CBCT); post-CBCT clinical analysis; clinical analysis using an operating microscope; and clinical analysis after Start X ultrasonic inserts in teeth with negative results in all previous analyses. Results. Periapical radiographic analysis revealed the presence of MB2 in four (8%) teeth, clinical analysis in 25 (50%), CBCT analysis in 27 (54%) and clinical analysis following CBCT and using an operating microscope in 27 (54%) and 29 (58%) teeth, respectively. The use of Start X ultrasonic inserts allowed one to detect two additional teeth with MB2 (62%). According to Vertucci's classification 48% of the mesiobuccal canals found were type I, 28% type II, 18% type IV and 6% type V. Statistical analysis showed no significant differences (p > 0.5) in the ability of CBCT to detect MB2 canals when compared with clinical assessment with or without an operating microscope. A significant difference (p < 0.001)was found only between periapical radiography and clinical/CBCT evaluations. Conclusion. Combined use of different methods increased the detection ofthe second canal in MB roots, but without statistical difference among CBCT, operating microscope, Start X and clinical analysis.     

Clinical Factors Associated with Apical Periodontitis Visible on Cone-beam Computed Tomography but Missed with Periapical Radiographs: A Retrospective Clinical Study

IntroductionCone-beam computed tomographic (CBCT) imaging is useful in detecting apical periodontitis, which is often missed in periapical (PA) radiographs. This study aimed to identify preoperative predictors correlated with the presence of apical periodontitis visible only in CBCT images and to investigate the important characteristics of such lesions.MethodsIn total, 332 consecutive patients with both PA radiographs and CBCT images were enrolled in this study. The patients’ clinical charts were reviewed retrospectively to collect information regarding their symptoms and diagnoses. Periapical lesions were assessed using a modified CBCT PA index by 2 endodontists. Patient-related factors (age, sex, and symptoms) and tooth-related factors (tooth type, location, pulp status, and pulpal diagnosis) were assessed to determine their relationships with the presence of apical periodontitis visible only in CBCT images.ResultsApical periodontitis was detected in 24.6% and 35.5% of untreated teeth by PA radiographs and CBCT images, respectively. In a multivariate logistic regression analysis, pulp necrosis was significantly correlated with the presence of apical periodontitis visible only in CBCT images (odds ratio = 5.401; 95% confidence interval, 1.911–15.265; P = .001); the involvement of molars showed borderline nonsignificant correlation (odds ratio = 2.843; 95% confidence interval, 0.990–8.164; P = .052). Lesion sizes smaller than 2 mm in diameter and the involvement of molars were significant factors of lesions visible only in CBCT images (P < .05).ConclusionsPulp necrosis was a preoperative predictor of apical periodontitis visible only in CBCT images. This research could provide a proper indication for CBCT imaging at diagnostic stages.     

Mesiobuccal and Palatal Interorifice Distance May Predict the Presence of the Second Mesiobuccal Canal in Maxillary Second Molars with Fused Roots

IntroductionThe aim of this study was to evaluate if the configuration of canal orifices can predict the presence of a second mesiobuccal canal (MB2) in maxillary second molars with fused roots.MethodsMaxillary second molars with fused roots (N = 150) were scanned in a micro–computed tomographic device (pixel size = 9 μm) and evaluated regarding the root fusion type and the incidence of the MB2 canal. The centers of the canal orifices were connected, and the angles formed by the intersection of these lines as well as their distances were measured and statistically compared (1-way analysis of variance). Specimens were then assigned to 2 groups according to the presence (n = 65) or absence (n = 50) of the MB2 canal and compared regarding the angles and interorifice distances using the Welch t test. A binary logistic regression model estimated the association between the interorifice distance, the fusion type, and the presence of the MB2 canal, whereas receiver operating characteristic curve analysis was performed to evaluate the diagnostic abilities of significant variables. The significance level was set at 5%.ResultsThe most common fusion types were 1 and 6, and MB2 canal incidence was 47.3%. No statistical difference was observed in the angles or interorifice distances among teeth with different fusion types (P > .05). Distances from the mesiobuccal (MB) to the distobuccal and palatal (P) canal orifices as well as the MB and P angles were significantly higher in the presence of an MB2 canal (P < .05). A binary logistic regression model revealed that MB-distobuccal and MB-P distances were significant in the presence of an MB2 canal (P < .05). Receiver operating characteristic analysis indicated that MB-P distance had acceptable diagnostic accuracy for the prediction of MB2 canal presence. Sensitivity (specificity) calculated from the MB-P distances of 4.0, 4.5, and 5.0 mm were 89.2% (36.5%), 76.9% (58.4%), and 44.4% (71.4%), respectively.ConclusionsMB-P interorifice distance is a strong predictor of the presence of the MB2 canal in maxillary second molars with fused roots.     

Prevalence of Second Mesiobuccal Canals in Maxillary First Molars Detected Using Cone-beam Computed Tomography,Direct Occlusal Access,and Coronal Plane Grinding

Introduction

The purpose of this study was to determine the prevalence of the second mesiobuccal canal (MB2) in 100 maxillary first molars using 3 independent methods and a combination method.

A Cone-beam Computed Tomographic Study of Root and Canal Morphology of Maxillary First and Second Permanent Molars in a Thai Population

Introduction

Understanding tooth anatomy is crucial for effective endodontic treatment. This study investigated the roots and root canal morphology of maxillary first and second permanent molars in a Thai population using cone-beam computed tomographic (CBCT) imaging.

The impact of different voxels and exposure parameters of CBCT for the assessment of external root resorptions: A phantom study

This study aimed to compare the effectiveness of the different voxel sizes and imaging parameters of cone beam computed tomography (CBCT) on the determination of external root resorption (ERR). ERRs were created in coronal, middle and apical regions. Depths (0.62–0.73 mm) and diameters (0.68–0.81 mm) of ERRs were measured using a digital calliper. Images were obtained in 0.125, 0.2, 0.25, 0.3 and 0.4 mm³ voxel sizes and at different currents. Data were analysed using Friedman and Wilcoxon signed‐rank tests at a level of P < 0.05. There was a difference between the parameters in determining the size of the ERR in coronal and middle regions (P < 0.05), but there was no difference in the apical region (P > 0.05). The change in current and exposure time did not make a difference in determining the dimensions of the ERRs (P > 0.05). Some voxel dimensions were more reliable in determining the depth and diameter of ERR in the coronal and middle region.     

Vertucci’s Root Canal Configuration of 14,413 Mandibular Anterior Teeth in a Brazilian Population: A Prevalence Study Using Cone-beam Computed Tomography

IntroductionThis cone-beam computed tomographic (CBCT)-based study evaluated the root canal configurations of mandibular anterior teeth in a large Brazilian population, along with the influence of sex and the frequency of symmetry between the contralateral teeth.MethodsOverall, 2543 CBCT scans, including those of 4773 lower central incisors (LCIs), 4835 lower lateral incisors (LLIs), and 4805 lower canines (LCs), were analyzed. The scans were obtained from a private radiologic clinic using the PreXion 3D device (Yoshida Dental Mfg Co, Ltd, Tokyo, Japan) with a 0.14-mm voxel size; exposure parameters of 90 kV, 4 mA, and 19 seconds; and a field of view of 80 × 80 mm. Root canal anatomy was analyzed according to the Vertucci classification. Sex influence on the canal distribution and symmetry between the contralateral teeth were analyzed. The data were analyzed statistically and were considered significant when P < .05.ResultsAll LCIs and LLIs had 1 root, whereas 2.4% of LCs had 2 roots. Two root canals were observed in approximately 20% of LCIs and LLIs and in approximately 11% of LCs. The most common configuration was type I followed by type III. Bilateral symmetry occurred in a majority of the individuals (ie, 91% in LCIs, 87% in LLIs, and 87% in LCs). No sex influence was noted with LLIs and LCs (P > .05). However, LCIs showed a higher prevalence of 2 canals in men (P < .05).ConclusionsThe prevalence of 2 root canals in the mandibular anterior teeth in Brazilians was approximately 20% for central and lateral incisors and 10% for canines.