Cone Beam Computed Tomography Machine Research Articles

Assessment of Mesiobuccal Canals in Endodontically Treated Teeth in Indore Population by Cone Beam Computed Tomography: A Cross-Sectional Study.

Owing to the complicated anatomical nature of maxillary molars, untreated root canals may directly affect the outcome of root canal therapy. Therefore, cone beam computed tomography (CBCT) scanis an important tool in the evaluation of root canal systems, particularly for the detection of the second mesiobuccal(MB2) canalin maxillary molars. The current study was undertaken to detect and evaluate filled/unfilled MB2 canals in endodontically treated, asymptomatic maxillary molars, and its correlation with periapical pathology by utilizing cone beam computed tomography (CBCT). A retrospective study of 80 CBCTs of patients underwent scanning for various treatment modalities, with asymptomatic endodontically treated permanent maxillary first molars selected. Data collection occurred between January and June 2023. CBCT machine used was KODAK 9000 (Rochester, NY: Carestream Health) (Complementary Metal Oxide Semiconductor {CMOS} sensor, continuous mode and 12-28 sec scan time, 90-500 μm voxel size, and 5x3.5 cm field of view {FOV}). The axial images at mid-root level were used to assess the presence of the MB2 canal. The study included 39 (48.8%) right maxillary first molars and 41 (51.3%) left maxillary first molars. Overall, in 62 (77.5%) maxillary first molars, MB2 was missed by the practicing dentist, and in 13 (16.3%) maxillary first molars MB2 canal was not present. Of all the maxillary first molars with MB2 canal (n=67), 53 (79.1%) canals had a periapical infection, five (7.5%) showed widening of periodontal ligament space whereas nine (13.4%) had no abnormality. MB2 canals were present in the majority of cases and most of the unfilled MB2 canals showed evidence of periapical radiolucencies and showed a direct impact on the prognosis.

The added effect of artifact reduction algorithm and ultra-low dose protocols on the accuracy of measurements obtained using Planmeca Viso G7 cone beam computed tomography

Objective The aim of this study is to evaluate the accuracy of linear and volumetric measurements using Planmeca Viso G7 cone beam computed tomography (CBCT) examinations acquired with ultra-low dose (ULD) and metal artifact reduction algorithm (ARA) protocols. Materials and methods Eight metallic spherical objects different in size with pre scanning diameter measurements using a calibrated digital caliper were fixed on a five dry human mandible. The real physical diameters and linear measurements between the metallic objects were measured. A CBCT acquisition was obtained four times with the same proper field of view, 150 μm and 100 Kv, in four scans using the Planmeca Viso G7 CBCT, machine acquisition was done with and without ARA, ULD, which is ARA, and ULD. Both acquisition protocols are inherited options in the Planmeca Viso G7 CBCT machine. All images were interpreted with the Planmeca Romexis software. Results Linear and volumetric measurements were found to have a nonstatistically significant difference with real measurements in the acquisition with ARA and ULD, but with a statistically significant difference with the other three acquisition sequences. Conclusions Using the ARA in combination with the ULD as an acquisition tool in the CBCT machine results in accurate linear and volumetric measurements, enhances image quality, and reduces metallic artifact with the lowest radiation dose.

Proposed Diagnostic Reference Levels in the Missouri/Southern Illinois Region Associated with Cone-beam Computed Tomography Use in Endodontics

IntroductionDiagnostic reference levels (DRLs) are intended to improve patient safety and ensure that patient ionizing radiation doses are as low as reasonably achievable. The purpose of this dosimetry study was to establish regional DRL levels for cone-beam computed tomography (CBCT) imaging for specialty endodontics. Another aim was to compare phantom-measured ionizing radiation dose index 1 (DI1) index doses to the manufacturer-provided dose area product (DAP) radiation output values for each of the CBCT machines studied, to ascertain their degree of correlation. DAP refers to the dose area product, a measure of radiation dose monitoring which represents the dose within the beam times the area within the beam at that position. MethodsA thimble ionization chamber and polymethyl methacrylate phantom were used to obtain DI1 values using the SEDENTEXTCT method from 21 different CBCT units. DRLs were calculated based on the 75th percentile (third quartile) of the median output values. ResultsThe proposed DRL from the CBCT units surveyed has a DAP value of 838 mGy cm2 and a DI1 value of 3.924 mGy. DAP versus DI1 values of 500.6 mGy cm2 versus 2.006 mGy, and 838 mGy cm2 versus 3.906 mGy represented the third quartile of the median values for the 4-cm × 4-cm and 5-cm × 5-cm field of views (FOVs), respectively. ConclusionsThe DI1 and DAP values strongly correlated when 3 outlier CBCT machines (J Morita Veraview X800) using a novel 360° (full rotation) acquisition mode were excluded. The importance of selectable exposure parameters as directly related to ionizing radiation output is illustrated among the CBCT units surveyed. Although the actual FOV that is selected is ultimately dictated by the specific clinical requirements, a 4-cm × 4-cm FOV is recommended for specialist endodontics practice, whenever clinically practical, based on the decreased ionizing radiation output, as compared to that from a 5-cm × 5-cm FOV.

Comparative Evaluation of Modified Kvaal’s Formula and Coronal Pulp Cavity Index in the Pune Population – A Cone-beam Computed Tomography-based Retrospective Study

ABSTRACT Introduction: The uniqueness of the human dentition serves its wide acceptance in the identification of individual in forensic science. Aim and Objectives: To estimate the accuracy of age by using modified Kvaal’s formula and coronal pulp cavity index (CPCI) and compare the standard error and establish the technique among the Pune population. Materials and Methods: Four hundred cone-beam computed tomography (CBCT) scans were randomly selected with satisfying the established criteria. The second premolar was included in the study and the maximum length of tooth, root, and pulp was measured using modified Kvaal’s method and CPCI by using Planmeca CBCT machine with Romexis-three-dimensional imaging software. Results: The results were analyzed using the Chi-square test and ANOVA. Modified Kvaal’s formula was found to be the better followed by CPCI in the estimation of age among Indians with lesser error in prior. Conclusion: Modified Kvaal’s formula is precise, noninvasive, and most reliable biomarker for age estimation than tooth-coronal index.

Assessment of the Nasopalatine Canal in Patients Requiring Dental Implants in the Maxillary Anterior Region Using Cone Beam Computed Tomography.

To assess the nasopalatine canal in patients requiring dental implants in the maxillary anterior region using cone beam computed tomography (CBCT). About 56 patients requiring dental implants in the maxillary anterior region of either gender reporting to the daily Outpatient Department, Department of Oral Medicine and Radiology aged between 18 and 60 years were selected. They were subjected to a CBCT scan using Newtom Giano CBCT machine (NewTom, Imola, Italy). Newtom New Technologysoftware and a slice thickness of 0.3 mm were used. For assessment of the implant site at the maxillary anterior region, alveolar bone width in the anterior region of the canal at the upper, middle, and lower third, incisive foramen diameter (IFD), nasopalatine canal length (NPCL), canal diameter in the floor of the nasal fossa and nasopalatine canal morphology was determined. Out of 56 patients, males comprised 30 and females 26. The mean bone height in 11 regions was 15.6±3.9, in 12, 16.2±2.7 mm, in 13 was 15.5±2.4 mm, in 21 was 13.7±4.2 mm, in 22 was 14.7±3.6 mm, in 23 was 16.7±1.5 mm. A non-significant difference was observed when comparing the bone height at different implant sites (p>0.05). The mean bone width at 3 mm and 6 mm from an alveolar crest in 11 regions was 4.3 mm and 5.3 mm, in 12 was 5.7 mm and 6.2 mm, in 13 was 3.7 mm and 4.6 mm, in 21 regions was 4.1 mm and 5.5 mm, in 22 regions was 4.6 mm and 5.7 mm and in 23 regions was 4.0 mm and 4.9 mm, respectively. A significant difference was observed when comparing the bone width at 3 mm and 6 mm at different implant sites (p<0.05).Nasopalatine canal type was A in 42 (75%), B in 13 (23.2%), and C in 1 (1.8%) patient. The mean alveolar bone width in the anterior region of the canal at the upper third was 10.1 mm, in the middle third was 7.4 mm, and in the lower third was 5.2 mm. The mean IFD was 4.6 mm, the NPCL was 13.5 mm, and the canal diameter on the floor of the nasal fossawas 3.8 mm. A significant difference was observed in comparing nasopalatine canal type (p<0.05). For the clinician to assess implant placement in the maxillary esthetic zone, CBCT imaging of the nasopalatine canal is crucial. It is possible to prevent intraoperative and postoperative complications such as hemorrhage, sensory impairment, osseointegration failure, and nasopalatine duct cyst formation.

Volumetric analysis of artifacts from fiducial markers under cone beam computed tomography

Computer aided implant surgery has been widely adopted in modern implant dentistry. However, absence of reliable anatomic landmarks for superimposing digital data sets for patients with terminal dentition or complete edentulism remained challenging. Utilization of additional fiducial markers intraorally as the reference points for the improvement of accuracy became crucial in implant digital workflow. Nevertheless, the choice of the material for fiducial markers should present the least radiographic artifacts under cone beam computed tomography (CBCT) for better accuracy. The aim of this invitro study was to investigate the volume of radiographic artifacts generated through different materials under the image of CBCT. Fifteen dental materials were selected and configured into cubic shape. All the materials were scanned initially with the laboratory scanner as the control groups. The samples were scanned by CBCT machine as test groups and the volume of artifact generated under CBCT images were compared and analyzed using 3D modeling software. Eleven out of fifteen materials could be recognized under CBCT images. Volumetric analysis reported that statistically significant differences among the materials could be noted, and the flowable composite resin presented the least volumetric difference. Lithium disilicate glass-ceramic, flowable composite resin, and gutta-percha presented the least deformation and maintained their cubic shapes. The results of the present study may imply that flowable composite resin compared to all ceramic materials, amalgam and gutta-percha may be a preferable choice when utilized as fiducial markers under CBCT images.

Cone beam computed tomography enhancement using feature‐embedded variational autoencoder with a perceptual loss function

AbstractImage‐Guided Radiation Therapy (IGRT) is a cancer treatment method. IGRT usually follows a fragmented treatment track. The weight loss of a patient causes the first treatment plan to be flawed. Medical experts can avert retaking Fan Beam Computed Tomography (FBCT) images before each session of the therapy if the Cone Beam Computed Tomography (CBCT), which is mounted on a Medical Linear Accelerator (LINAC), gives high‐quality images. Rather than improvising the CBCT machine, deep‐learning techniques can be used to enhance the CBCT images. This paper proposes a Feature‐Embedded Variational AutoEncoder (FE‐VAE) for CBCT image enhancement. A feature embedding is incorporated using a MultiResUNet‐based feature extractor to preserve structural information in the input image. A perceptual loss function, which is the product of Mean Absolute Error (MAE) and inverse Structural Similarity Index Measure (SSIM), is proposed in this work. The model is trained using Head‐and‐Neck (H&amp;N) CBCT‐FBCT pairs of 59 cancer patients. Our proposed architecture successfully generates images much closer to the ground truth FBCT images. The model gives an average peak signal‐to‐noise ratio of 32.89 dB, mean squared error of 297.36, MAE of 32.37 HU, and SSIM of 0.99. The trained model gave the least deviated SSIM and MAE, implying that the model is well‐optimised. The experimentation with different losses proves the prominence of the proposed loss function. The visual quality of the results obtained is also comparable with the ground truth. The results indicate that the model produces enhanced CBCT images. Hence, the proposed FE‐VAE is useful in fractionated radiotherapy to minimise the number of scanning sessions for replanning the dosimetry.

Reliability of Grayscale Value for Bone Density Determination in Oral Rehabilitation using Dental Implants.

Quality and quantity of jaw bones have been previously classified in literature using different methods. Imaging modalities such as computed tomography (CT), successfully determine bone density of jaws. This study aims to establish the role of cone-beam CT (CBCT) in determining the density of cortical and cancellous bones at different jaw sites. Eighty-three possible implant sites in healthy patients were evaluated using NewTomGiano CBCT machine. Cross-sections were obtained and cortical and cancellous bone densities on different aspects of the virtual implant in terms of Hounsfield unit (HU) were determined using New Net Technologies software version 6.1 and were classified according to software from D1 to D4. Data were entered into SPSS software (version 19.0) and were statistically analyzed. The mean HU showed the highest value for cortical and cancellous in the anterior mandible (mean HU 1874.01 and 1131.73, respectively) followed by the posterior mandible (mean HU 1789.20 and 872.95, respectively) and least in posterior maxilla (mean HU 1068.26 and 830.04, respectively). Maximum D1 bone type was found in cortical bone and D2 bone type was noted in cancellous bone area. Males showed very highly significant cortical bone thickness (P < 0.001) whereas females showed more cancellous bone thickness but the results were nonsignificant. A high degree of concordance between different regions of jaw bones with a strong correlation between the four bone types was obtained. Bone density plays a pivotal role in determining the prognosis of the implant. CBCT has proven to be beneficial in bone density analysis.

Do cone-beam computed tomography low-dose protocols affect the evaluation of the temporomandibular joint?

There is no established acquisition protocol based on scientific evidence for the acquisition of cone-beam computed tomography (CBCT) exams to evaluate the temporomandibular joint (TMJ). To evaluate the influence of acquisition protocols and jaw positioning on the diagnostic accuracy of TMJ condylar morphological alterations (CMA), dimension, position and excursion. Thirty-six TMJs on 18 dry skulls were imaged using a CBCT unit (OP300 Maxio, Instrumentarium, Tuusula, Finland) at two exposure settings (4.5 and 6.3mA), three voxel resolutions (0.085, 0.125 and 0.280 mm), three jaw positions (concentric, anteriorised and posteriorised) and three jaw excursions (normoexcursion, hyperexcursion and hypoexcursion). The macroscopic anatomy examination and high-resolution CBCT images were used as ground truth for CMA. Twenty-five TMJs had at least one CMA with 11 healthy TMJs serving as controls. Three experienced oral and maxillofacial radiologists evaluated the parasagittal images for the presence of CMA, position and excursion and measured dimensions. The area under the ROC curve, sensitivity and specificity were calculated. Weighted Kappa (α=0.05) was used to determine intra- and interexaminer reliability and comparisons between dependent variables analysed by Analysis of Variance at an a prior level of significance of 0.05. The agreement of the evaluation of the position and excursion with the reference standard was high, independent of the protocol (range, 0.75-0.91). Various combinations of acquisition protocols and jaw position did not influence the CMA evaluation. Erosion was overdiagnosed in protocols with larger voxel sizes and the detection of osteophytes greater in images with smaller voxel sizes. The anteroposterior dimension was greater in the open jaw position (p < .05). CBCT protocols using reduced radiation exposure from the CBCT machine evaluated in this study can be used to assess condylar morphology, dimension, position and excursion, without compromising diagnostic performances for these parameters.

Current status of cone-beam computed tomography teaching in Brazilian undergraduate endodontic programs - A web-based survey.

This study aimed to assess the current status of cone-beam computed tomography (CBCT) education in Brazilian undergraduate Endodontic programs. One hundred program directors were emailed. The questionnaire asked whether the CBCT topic was included in the program, the availability of a CBCT machine, and, the total length of the dental program. For the group that does not teach, seven questions discussed the reasons for not teaching and whether another subject included this topic. For the programs that included CBCT, seven questions discussed the number of hours included, and the impression of the program directors with the quality of the teaching. The chi-square test was used for the correlation between the availability of the CBCT machine and the length of the dental program with the inclusion of the topic. Thirty-five program directors replied to the questionnaire. Twenty-six (74.3%) reported that the topic of CBCT is not included in their programs. There was no impact of the availability of a CBCT machine on the inclusion of the topic (p>0.05). The increased length of the dental program decreased the inclusion of the topic (p<0.05). Fifty percent of the directors replied that lack of time is the reason for not including the topic. Among the programs that include CBCT, the majority (55.6%) deliver 3-5h of lectures. The practical activities range from 1 to 5h or more. The majority (77.8%) of the directors are satisfied with the content delivered and 44.4% understand that the students are competent in the interpretation of CBCT images. The majority of the Endodontic undergraduate programs in Brazil do not include CBCT in the program. The availability of a CBCT machine does not impact the inclusion of the topic, the increased duration of the dental program decreases the inclusion of the CBCT topic.

Comparison of subjective image analysis and effective dose between low-dose cone-beam computed tomography machines.

To compare the cone-beam computed tomography (CBCT) image quality and effective dose between low-dose scanning and standard manufacturer-recommended protocols among different CBCT units. Three human-equivalent phantoms were scanned using the ultra-low-dose (ULD), low dose (LD), and standard dose (STD) modes of ProMax 3D Mid (Planmeca Oy, Helsinki, Finland) and Orthophos SL (Sirona, Bensheim, German) for the CBCT images. The quality of the dental anatomical images was assessed by four experienced oral and maxillofacial radiologists using a 5-point Likert scale. OnDemand3D (Cybermed Co., Seoul, Korea) was used as the third-party software for viewing. The percentage of absolute agreement was calculated to determine intra- and interrater agreements among the observers. The effective doses for all CBCT scanning protocols were also calculated. The STD protocol yielded a higher image quality than did the ULD and LD protocols in both ProMax 3D Mid and Orthophos SL. The ULD and LD protocols demonstrated an "acceptable-to-good" sense of visual perception of the CBCT images. The visibility scores significantly differed between the ULD and LD and the STD protocols in ProMax 3D Mid and Orthophos SL, except for the 120-kVp setting in ProMax 3D Mid. The average intra- and interrater agreement scores ranged from 0.63 to 0.89 and from 0.44 to 0.76, respectively. The ULD and LD protocols reduced the radiation dose sixfold compared with the STD protocol. High-tube-voltage protocols could remarkably reduce the imaging dose without degrading the image quality. Specifically, ULD and LD CBCT protocols may be adopted as routine practice for diagnosis and treatment planning.

Quantitative Analysis of Cone-Beam Computed Tomography Artifacts Induced by Nonmetallic Root Canal Filling Materials Using Different Fields of View: In Vitro Study.

Cone-beam computed tomography (CBCT) imaging artifacts can hinder accurate diagnosis of several conditions. The aim of this study was to quantify CBCT artifacts created by nonmetallic root canal filling materials using two fields of view (FOV). Root canals of twenty extracted maxillary central incisors (n = 20) were instrumented and randomly divided into four equal groups: canals in Group 1 were filled with gutta-percha, canals in Group 2 with mineral trioxide aggregate (MTA) and gutta-percha, canals in Group 3 with gutta-percha and glass-fiber posts, and canals in Group 4 with MTA and glass-fiber posts. Each tooth was mounted on a silicon block and scanned three times using a CBCT machine, first with a prefilling scan (control) and then with postfilling scans, using two different FOV (40∗50 mm and 80∗50 mm). Imaging software was used to measure grayscale pixel values of canal cross sections. Data were analyzed using t-test and paired t-test statistical tests, with statistical significance set at p ≤ 0.05. Dentin at the apical and middle third of the teeth showed a significant decrease in minimum grayscale values in association with gutta-percha (p = 0.027, p = 0.034). However, a wide 80∗50 FOV showed a significant increase in maximum grayscale values of coronal (p = 0.048) and apical dentin (p = 0.049). Glass-fiber posts in middle third cross sections also corresponded to an increase in maximum grayscale values (p = 0.018). Gutta-percha produced dark band artifacts in the root's middle and apical thirds, whereas white streak artifacts were produced by gutta-percha in the coronal third and glass-fiber posts in the coronal and middle thirds when imaged with a wider FOV. A smaller FOV is therefore recommended for CBCT imaging, as it produces fewer artifacts.

Correlation analysis between radiation exposure and the image quality of cone-beam computed tomography in the dental clinical environment.

PurposeThis study was conducted to measure the radiation exposure and image quality of various cone-beam computed tomography (CBCT) machines under common clinical conditions and to analyze the correlation between them.Materials and MethodsSeven CBCT machines used frequently in clinical practice were selected. Because each machine has various sizes of fields of view (FOVs), 1 large FOV and 1 small FOV were selected for each machine. Radiation exposure was measured using a dose-area product (DAP) meter. The quality of the CBCT images was analyzed using 8 image quality parameters obtained using a dental volume tomography phantom. For statistical analysis, regression analysis using a generalized linear model was used.ResultsPolymethyl-methacrylate (PMMA) noise and modulation transfer function (MTF) 10% showed statistically significant correlations with DAP values, presenting positive and negative correlations, respectively (P<0.05). Image quality parameters other than PMMA noise and MTF 10% did not demonstrate statistically significant correlations with DAP values.ConclusionAs radiation exposure and image quality are not proportionally related in clinically used equipment, it is necessary to evaluate and monitor radiation exposure and image quality separately.

Radiomorphometric analysis of the clivus – A soothsayer of age and gender

Purpose: Skull is the most studied skeletal remaining as enamel and bones are the last ones to disintegrate after death. The clivus is one such dense part of the skull base and most of the time it is recovered intact from a damaged or incinerated skull and can be used as an indicator in identification. The present study is aimed to perform a radiomorphometric analysis of the clivus using cone-beam computed tomography (CBCT) and to assess its pertinence in age and gender estimation. Materials and Methods: The CBCT images of 254 (162 males, 92 females) subjects were obtained from New tom Giano HR (QR SRL Company, Verona, Italy) CBCT machine at 90 kVp, 6 mA for 7.2 s at the field of view (16 × 18), voxel size of 300 in the age group of 6–70 years were chosen. The clivus widths and lengths were measured using NNT software programs on axial and sagittal reconstructed images. Results: Mean clivus lengths and widths were significantly different in male and female patients. Bivariate correlations showed that there was a stronger association of the clivus lengths and widths to age when considered a linear combination as opposed to when taken individually in both female and male patients. Association between the linear combination of the clivus lengths and widths with age was found to be the highest in female patients among all the results (R = 0.553). All the above results were statistically significant (P < 0.05). Conclusion: CBCT measurements of clivus dimensions can be used reliably for anthropometric analysis as they are precisely associated with age and gender. Hence, it can be concluded that these dimensions can be used as a supplementary or only parameter when other parameters are uneventful in medicolegal cases.

Pre-implant evaluation of quantity and quality of mandibular bone in male diabetes mellitus patients using cone-beam computed tomography: A case–control study

Objectives: This study was designed to evaluate and compare the quantity and quality of mandibular bone in the first molar region in male type 2 diabetes mellitus (T2DM) patients with healthy controls using cone-beam computed tomography (CBCT) imaging technique. The bone characteristics in T2DM patients were correlated with diabetes duration. Materials and Methods: The study included 25 male diabetic patients and 25 nondiabetic male patients with missing mandibular 1st molar, in the age group ranging from 35 to 60 years. HDX WILL CBCT machine utilized to obtain CBCT images. Bone density and quantitative linear measurements were performed in OnDemand software, along with glycated hemoglobin levels of diabetic patients. The obtained data were subjected to statistical analysis using the SPSS software version 20.0. Results: Type 2 diabetic patients had greater bone density as compared to controls. The height of bone is less in diabetic patients than in nondiabetics, and other quantitative linear measurements were found similar in both groups. Conclusion: This study concluded that CBCT can be used in preimplant planning and helps the clinician assess bone measurements and bone density.

Assessment of Anterior Loop of Inferior Alveolar Nerve – A Cone Beam Computed Tomography Study

Introduction: The anterior loop (AL) of the inferior alveolar nerve (IAN) and the mental foramen (MF) are important anatomical structures that should be taken into consideration during preoperative planning in the anterior mandibular region. This study aims to assess the prevalence, length, and type of the AL of the IAN in males and females in a South Indian population. Additionally, the distance from the MF to the lower border of the mandible is assessed. Materials and Methods: A total of 115 cone-beam computed tomography (CBCT) scans of 230 sides of mandibles were taken using a Carestream Select CS9300 CBCT machine (Carestream Dental LLC, Atlanta, USA). The scans were selected from archives and divided into three different age groups (<40, 41–60, >61 years). The scans were analyzed to detect the canal of the AL of the inferior alveolar nerve canal (IANC). The IANC, along with the AL canal and part of the incisive nerve canal, was traced using the CS 9300 software. The length of the mandibular nerve was measured for each patient in cross-sectional and panoramic views. Results: The AL was present in 92.6% of the 115 participants. Overall anterior loop length ranged between 0.9 and 15.2 mm. The mean length of AL in panoramic view on the right side was 3.284 ± 2.314 mm and it was 3.015 ± 2151 mm on the left side. Y-shaped AL was more predominant when compared to T-shaped AL in the sample. Conclusion: The prevalence of AL was relatively higher in subjects ranging from 41 to 60 years with a slight increase in female predominance.

When to consider the use of CBCT in endodontic treatment planning in adults

With the recent publication of European Society of Endodontology (ESE) position statements, newly proposed three-dimensional (3D) classification for external cervical resorption and new techniques such as guided access using 3D printed splints, cone beam computed tomography (CBCT) has never been more important in endodontics. Furthermore, CBCT machines are becoming more affordable, resulting in imaging being more accessible in primary and secondary care. This, aligned with higher resolution images at lower effective doses, means CBCT must now be considered when planning and delivering a range of endodontic procedures. CPD/Clinical Relevance: To review the use of CBCT in endodontics and raise awareness of its indications in primary and secondary care.

A novel deep learning system for multi-class tooth segmentation and classification on cone beam computed tomography. A validation study

ObjectivesAutomatic tooth segmentation and classification from cone beam computed tomography (CBCT) have become an integral component of the digital dental workflows. Therefore, the aim of this study was to develop and validate a deep learning approach for an automatic tooth segmentation and classification from CBCT images. MethodsA dataset of 186 CBCT scans was acquired from two CBCT machines with different acquisition settings. An artificial intelligence (AI) framework was built to segment and classify teeth. Teeth were segmented in a three-step approach with each step consisting of a 3D U-Net and step 2 included classification. The dataset was divided into training set (140 scans) to train the model based on ground-truth segmented teeth, validation set (35 scans) to test the model performance and test set (11 scans) to evaluate the model performance compared to ground-truth. Different evaluation metrics were used such as precision, recall rate and time. ResultsThe AI framework correctly segmented teeth with optimal precision (0.98±0.02) and recall (0.83±0.05). The difference between the AI model and ground-truth was 0.56±0.38 mm based on 95% Hausdorff distance confirming the high performance of AI compared to ground-truth. Furthermore, segmentation of all the teeth within a scan was more than 1800 times faster for AI compared to that of an expert. Teeth classification also performed optimally with a recall rate of 98.5% and precision of 97.9%. ConclusionsThe proposed 3D U-Net based AI framework is an accurate and time-efficient deep learning system for automatic tooth segmentation and classification without expert refinement. Clinical significanceThe proposed system might enable potential future applications for diagnostics and treatment planning in the field of digital dentistry, while reducing clinical workload.

Effect of Different Voxel Sizes on Accuracy of 2D and 3D Mandibular Linear Measurements Using CRANEX® 3D Cone Beam Computed Tomography Machine: Preclinical Study

Aim To assess the accuracy of linear measurement obtained from CBCT images in 3D volumetric rendering and multiplanar slices with different voxel sizes. Methodology: 9 mandibles with twelve radioopaque markers fixed on each one were imaged using CRANEX® 3D CBCT machine. Each mandible was imaged twice with voxel sizes 250 μm and 350 μm. 2D and 3D linear measurements from CBCT images were compared to the real physical measurements taken by a digital caliper. Software measurements were recorded twice by the principal investigator and once by the supervising professor. Intra- and inter-observer agreements were assessed using Intra-Class Correlation Coefficient (ICC). SPSS®IBM Version 24 and MedCalc® version 12.1 for Windows were used for statistical analysis. Results: CBCT 2D measurements with voxel sizes of 250μ and 350μ showed a mean difference= 0 mm both with 95% of difference being -0.6 mm above or 0.7mm below and-0.5 mm above or 0.6 mm below the Gold Standard respectively. CBCT 3D measurements with voxel sizes of 250μ and 350μ showed a mean difference= 0 mm both with 95% of difference being -0.5 mm below or 0.5 mm above and -0.6 mm above or 0.7 mm below the Gold Standard. Intra-observer and inter-observer reliability regarding all measurements showed excellent agreement. Conclusions: 2D and 3D measurements driven from CBCT images with voxel size of 350 μ are accurate as measurements driven from CBCT images with voxel size of 250 μ with less radiation delivered to the patient. 2D and 3D CBCT measurements driven from CBCT are reliable.

DIAGNOSTIC ACCURACY OF INTRAORAL, EXTRAORAL, AND CBCT-GENERATED BITEWINGS FOR DETECTING APPROXIMAL CARIES AND PERIODONTAL BONE LOSS

<h3>BACKGROUND</h3> With the current coronavirus disease pandemic, dental offices are trying their best to limit intraoral imaging. One solution to overcome this problem is to use extraoral imaging techniques. <h3>OBJECTIVE(S)</h3> The objective of this study was to evaluate the diagnostic accuracy of intraoral bitewings, extraoral bitewings generated by a panoramic machine, and cone beam computed tomography (CBCT)–generated bitewings with 180° and 360° rotations in the detection of dental caries and bone loss. <h3>STUDY DESIGN</h3> The study examined carious defects, alveolar bone levels, and interdental vertical defects in the posterior mandible in 100 interproximal surfaces in a dry human skull. Simulated cavities were created at specific locations and interdental defects were created on both buccal and lingual surfaces where measured amounts of bone were removed to simulate bone loss. Physical measurements of bone removed served as the gold standard. Intraoral bitewings were acquired using photostimulable phosphor sensors with a Kavo LM/CM109 x-ray tube at 70 kVp,7mA and 0.125 seconds. Extraoral bitewings were acquired with a J. Morita panoramic unit at 90 kVp,7mA and 5.5 seconds. CBCT scans were acquired with the J. Morita 3D Accuitomo at 90 kVp and 7 mA setting with a 40 × 40 mm FOV in the Hi-Res-Mode. Four examiners scored the presence and extent of caries and performed alveolar bone measurements. <h3>RESULTS</h3> No statistically significant results were noted with all imaging modalities for the diagnostic efficacy and linear measurement of the defects. Kappa analysis for interoperator reliability was very high. <h3>DISCUSSION/CONCLUSIONS</h3> The diagnostic accuracy of extraoral bitewings generated from panoramic and CBCT machines for detecting dental caries and periodontal bone loss is comparable for all imaging modalities tested. <h3>FUTURE DIRECTIONS</h3> In this study there was no metallic scatter like in clinical situations, so future studies that will incorporate varying degrees of metallic scatter must be done to evaluate the diagnostic efficacy.