Cone Beam Computed Tomography Devices Research Articles

Novel AI-based tool for primary tooth segmentation on CBCT using convolutional neural networks: A validation study.

Primary teeth segmentation on cone beam computed tomography (CBCT) scans is essential for paediatric treatment planning. Conventional methods, however, are time-consuming and necessitate advanced expertise. The aim of this study was to validate an artificial intelligence (AI) cloud-based platform for automated segmentation (AS) of primary teeth on CBCT. Its accuracy, time efficiency, and consistency were compared with manual segmentation (MS). A dataset comprising 402 primary teeth (37 CBCT scans) was retrospectively retrieved from two CBCT devices. Primary teeth were manually segmented using a cloud-based platform representing the ground truth, whereas AS was performed on the same platform. To assess the AI tool's performance, voxel- and surface-based metrics were employed to compare MS and AS methods. Additionally, segmentation time was recorded for each method, and intra-class correlation coefficient (ICC) assessed consistency between them. AS revealed high performance in segmenting primary teeth with high accuracy (98 ± 1%) and dice similarity coefficient (DSC; 95 ± 2%). Moreover, it was 35 times faster than the manual approach with an average time of 24 s. Both MS and AS demonstrated excellent consistency (ICC = 0.99 and 1, respectively). The platform demonstrated expert-level accuracy, and time-efficient and consistent segmentation of primary teeth on CBCT scans, serving treatment planning in children.

Radiographic Recognition of Mental Nerve for Secured Dental Implant Placement by Cone-Beam Computed Tomography in Mosul City Population.

The study aims to estimate precisely the different levels of mental loop and foramina in the Mosul population of Nineveh governorate in Iraq. It is a cross-sectional study of a previously saved database in the cone-beam computed tomography device. The study sample was 357 patients selected randomly from the database of patients at the Oral Radiology Unit at the Maxillofacial Department in Al-Salam Teaching Hospital. The study variables are mental foramen (MF) position, shape, radiograph appearance, and mental loop presence and direction. The results show that the age group from 19 to 30 years shows the highest percentage (40.1%). Females show more than half of the cases (59.7%). The MF position's highest percentage is shown in 2 areas with the slight differences. These are the long axis of first premolar and the area between first premolar and second premolar (42.6%, 40.9). According to shape variation round shapes are the uppermost percent (53.8%). More than 60% of cases (66.1%) show continuity with the inferior alveolar canal and 50% show no loop presence, and the mental nerve leaves the foramen in a perpendicular direction. In conclusion localization of the MF, nerve, and its loop precisely in both horizontal and vertical directions, both hard and soft tissues in a continuous view. Before arranging any surgical procedure, anatomic markers are crucial. To reduce the danger of harm to the foramen region, the authors thus advised cone-beam computed tomography before scheduling implant surgery, particularly in the mental region of the jaw.

Effect of different cone beam computed tomography settings on artifact production in titanium and zirconia dental implants: An in vitro study.

The use of dental implants in the treatment of edentulous patients is increasing. Zirconia implants are an alternative to titanium implants, offering advantages in terms of aesthetics and biological compatibility. However, the number of artifacts observed on radiographic images with zirconia implants compared to titanium implants is yet to be determined. The purpose of this study was to evaluate the impact of different cone-beam computed tomography (CBCT) parameters on the production of artifacts in zirconia and titanium implants. A dry human mandible was coated with wax to simulate human soft tissues and examined. Subsequently, titanium and zirconia implants were placed at the same points in the posterior region of the mandible. The production of artifacts on CBCT scans was evaluated using 2 parameters. The first parameter, the standard deviation within the region of interest (SDROI), is based on a comparison of the gray levels at implant and control areas. The second parameter was the contrast-to-noise ratio (CNR), which was evaluated for different protocols created by various combinations of the field of view (FOV) area, milliampere [mA] intensity and metal artifact reduction (MAR) programs. The study found that zirconia implants produced more artifacts than titanium implants. However, the production of artifacts in zirconia implants could be significantly reduced by increasing the mA values, performing CBCT scans with smaller FOV areas, and enabling MAR programs. The production of artifacts is a disadvantage of zirconia implants, but this drawback can be mitigated by selecting appropriate protocols for the CBCT device.

Diagnostic value of cone beam computed tomography for root canal morphology assessment – a micro-CT based comparison

ObjectivesThe aim of this study was to assess cone beam computed tomography (CBCT) as a root canal anatomy diagnostic tool by comparison with micro-CT gold-standard.Materials and methods216 two-rooted mandibular molars were first scanned in a CBCT device (200 μm voxel size) and posteriorly in a micro-CT scanner (19.61 μm). The volumes were sequentially screened to classify main root canal anatomy according to Vertucci classification, and for the presence of lateral canals and apical deltas, in both mesial and distal roots.ResultsBoth methods revealed a higher prevalence of Vertucci Type II and IV in the mesial root, and Vertucci Type I in the distal root. The percentage of agreement for main root canal anatomy classification between CBCT and micro-CT scores was high (85.2%).ConclusionSensibility to detect both lateral canals and apical deltas with CBCT was low. These results attest to the fact that minor anatomical changes might be difficult to identify with CBCT imaging, hampering its diagnostic value.

Cone-Beam CT of the Extremities in Clinical Practice.

Cone-beam CT (CBCT) is a promising tool with increasing applications in musculoskeletal imaging due to its ability to provide thin-section CT images of the appendicular skeleton and introduce weight bearing, which accounts for loading forces that typically interact with and affect this anatomy. CBCT devices include an x-ray source directly opposite a digital silicon detector panel that performs a single rotation around an object of interest, obtaining thin-section images. Currently, the majority of research has been focused on the utility of CBCT with foot and ankle pathologic abnormalities, due to the complex architectural arrangement of the tarsal bones and weight-bearing nature of the lower extremities. Associated software can provide a variety of options for image reconstruction, including metal artifact reduction, three-dimensional biometric measurements, and digitally reconstructed radiographs. Advancements in this technology have allowed imaging of the knee, hip, hand, and elbow. As more data are published, it is becoming evident that CBCT provides many additional benefits, including fast imaging time, low radiation dose, lower cost, and small equipment footprint. These benefits allow placement of CBCT units outside of the traditional radiology department, including the orthopedic clinic setting. These technologic developments have motivated clinicians to define the scope of CBCT for diagnostics, surgical planning, and longitudinal imaging. As efforts are made to create standardized protocol and measurements, the current understanding and surgical approach for various orthopedic pathologic conditions will continue to shift, with the hope of improving outcomes. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Image Guided Intraoperative Radiation Therapy After Surgical Resection of Brain Metastases: A First In-Human Feasibility Report

PurposeA correct placement of the applicator during intraoperative radiotherapy (IORT) for brain metastasis is of paramount importance, in order to deliver a precise and safe treatment. The applicator-to-surface contact assessment cannot be performed under direct observation, as the applicator itself limits the visual range. No image-guided (IG) verification is currently performed intracranially. We hypothesize that IG-IORT would assure a more precise delivery in the target area. We describe our workflow in a first in-human experience. Methods and MaterialsPhantom-based measurements were performed to reach the best cone-beam computed-tomography (CBCT) imaging quality possible. Once defined, a clinical feasibility study was initiated. An in-room CBCT device is used to acquire intraoperative images after placing the applicator. Repositioning the applicator is thereafter discussed with the surgeon, according to the imaging outcomes, if required. ResultsAn optimal image quality was achieved with 120-kV voltage, 20-mA current and a tube current–time product of 150 mAs. An additional 0.51–mSv patient exposure was calculated for the entire procedure. The wide dynamic range (−600 HU to +600 HU) of CBCT and a 27-HU mean CT values difference between brain tissue and spherical applicator allows distinguishing both structures. In this first in-human experience, the applicator was repositioned after evidencing air gaps, assuring full applicator-to-surface contact. ConclusionThis first in-human procedure confirmed the feasibility of kilovoltage IG-IORT in a neurosurgical setting. A prospective study has been initiated and will provide further dosimetric details.

Reduction of cone-beam CT artifacts in a robotic CBCT device using saddle trajectories with integrated infrared tracking.

Cone beam computed tomography (CBCT) is widely used in many medical fields. However, conventional CBCT circular scans suffer from cone beam (CB) artifacts that limit the quality and reliability of the reconstructed images due to incomplete data. Saddle trajectories in theory might be able to improve the CBCT image quality by providing a larger region with complete data. Therefore, we investigated the feasibility and performance of saddle trajectory CBCT scans and compared them to circular trajectoryscans. We performed circular and saddle trajectory scans using a novel robotic CBCT scanner (Mobile ImagingRing (IRm); medPhoton, Salzburg, Austria). For the saddle trajectory, the gantry executed yaw motion up to using motorized wheels driving on the floor. An infrared (IR) tracking device with reflective markers was used for online geometric calibration correction (mainly floor unevenness). All images were reconstructed using penalized least-squares minimization with the conjugate gradient algorithm from RTK with voxel size. A disk phantom and an Alderson phantom were scanned to assess the image quality. Results were correlated with the local incompleteness value represented by , which was calculated at each voxel as a function of the source trajectory and the voxel's 3D coordinates. We assessed the magnitude of CB artifacts using the full width half maximum (FWHM) of each disk profile in the axial center of the reconstructed images. Spatial resolution was also quantified by the modulation transfer function at 10% (MTF10). When using the saddle trajectory, the region without CB artifacts was increased from 43 to 190mm in the SI direction compared to the circular trajectory. This region coincided with low values for . When was larger than 0.02, we found there was a linear relationship between the FWHM and . For the saddle, IR tracking allowed the increase of MTF10 from 0.37 to 0.98 lp/mm. We achieved saddle trajectory CBCT scans with a novel CBCT system combined with IR tracking. The results show that the saddle trajectory provides a larger region with reliable reconstruction compared to the circular trajectory. The proposed method can be used to evaluate other non-circulartrajectories.

Influence of the metal post material, tooth location in the dental arch, and metal artifact reduction tool on vertical root fracture diagnosis in cone beam CT.

This study aimed to evaluate the influence of the metal post composition, tooth location in the dental arch, and metal artifact reduction (MAR) on vertical root fracture (VRF) diagnosis in cone beam computed tomography (CBCT). Twenty-two unirradicular premolars (12 sound and 10 fractured) and two alveolar sockets of a mandible (anterior and posterior regions) composed the sample. CBCT scans of each tooth with a metal post placed into the root canal-silver-palladium (Ag-Pd), cobalt-chromium (Co-Cr), or nickel-chromium (Ni-Cr)-were individually acquired for each mandibular region, and two conditions of MAR, using a OP300 device (Instrumentarium, Finland). Images were assessed by five evaluators independently for VRF detection. Diagnostic values were calculated and compared among all groups using multi-way ANOVA with Tukey post hoc test to investigate the effect of post material, anatomical region, and MAR on VRF diagnosis (α = 0.05). Values of area under the receiver operating curve and specificity were not influenced by the studied factors (p > 0.05). Sensitivity was influenced by the MAR in both mandibular regions (p < 0.05). In the anterior region, sensitivity values increased when the MAR was enabled, regardless of the metal post material (p < 0.05). Similar behavior was noticed in the posterior region for Ni-Cr (p < 0.05) but not for Ag-Pd and Co-Cr posts (p > 0.05). The MAR improved the sensitivity in VRF diagnosis for all tested metal posts in the mandibular anterior region and for the Ni-Cr post in the mandibular posterior region. Therefore, for images obtained in the OP300 CBCT device, activation of the MAR is suggested in these cases.

Comparison of CBCT radiation doses with conventional radiographs in TMJ imaging using Monte Carlo simulations.

Three-dimensional imaging methods are widely used for evaluation of bony changes of temporomandibular joint (TMJ). Besides, lateral and posterio-anterior TMJ projections in both closed- and open-jaw positions for each temporomandibular joint are used as two-dimensional diagnostic tools. The purpose of the present study was to compare effective and mean organ absorbed doses of plain radiography techniques with those of different modalities of cone beam computed tomography (CBCT) scanning of an adult's temporomandibular joint. PCXMC 2.0 software was used to calculate mean organ and effective doses. A NewTom CBCT device (Newtom 5G XL; QR systems; Verona, Italy) was simulated at 360° rotation using a 6 × 6cm2 FOV in standard and high-resolution modes. Lateral and posterio-anterior TMJ plain projections were simulated according to recommendations of the manufacturer of the Planmeca ProMax® 2D S3 device. Doses for both projections were simulated with Monte Carlo methods and the International Commission on radiological protection adult reference computational phantoms. The highest mean organ absorbed doses occurred in bone surfaces, salivary glands, and skull for posterio-anterior TMJ and lateral TMJ, and for CBCT scanning in all examinations. The effective doses of posterio-anterior and lateral TMJ plain radiographs were found to be higher than those of the Standard Mode-Eco Scan CBCT. Therefore, the lowest effective dose was calculated in Standard Mode-Eco Scan CBCT. It is concluded that NewTom 5G XL Standard Mode-Eco Scan CBCT can be used instead of plain radiographs (lateral and posterio-anterior TMJ) in temporomandibular joint imaging as it allows visualizing the three-dimensional structure of the temporomandibular joint as an advantage.

Assessment of Periapical Status in Posterior Root Canal-Treated Teeth Using Cone Beam Computed Tomography in the Iranian Population

Background: Periapical radiolucency occurs due to root canal infections. In this respect, effective root canal treatment and appropriate coronal restoration can aid in preventing these lesions. Thus, the present study aimed to assess the periapical status in posterior root canal-treated teeth by cone-beam computed tomography (CBCT) in the Iranian population. Methods: The CBCT images of 210 patients (475 endodontically treated molars and premolars) referred to the Hamadan Dental School (from 2020 to 2022) were evaluated in this observational study. The images were obtained by a NewTom 3G CBCT device (NewTom, Verona, Italy) with an FOV of 6×6 inches at 110 kVp and varying milliampers and exposure times according to the patient’s age and body size. They were observed by two maxillofacial radiologists who recorded the periapical status, coronal seal, and endodontic treatment quality of root canal-treated teeth. The Chi-square test was used for data analysis (P≤0.05). Finally, the periapical lesion was determined, along with its association with gender, type of tooth, endodontic treatment quality, and appropriate restoration. Results: The results revealed no significant association between periapical radiolucency and gender. The prevalence of periapical lesions was higher in males aged 25–50 years, but no significant correlation was found in this regard. There was no significant relationship between tooth type and the presence of periapical lesions, while it had the highest prevalence in maxillary molars. Endodontic treatment quality and coronal restoration showed significant correlations with the presence of periapical radiolucency. Conclusion: There was no significant association between the presence of periapical radiolucency and gender and age. The prevalence of periapical lesions was higher in males. Cases with poor endodontic treatment and poor restoration demonstrated the highest prevalence of periapical lesions.

Effect of Different Cone Beam Computed Tomography Devices and Protocols on Image Quality for the Evaluation of Periodontal Structures

AbstractThe quality of Cone Beam Computed Tomography (CBCT) images is directly influenced by scanning and visualization protocols. Evaluate the subjective quality of the Cone Beam Computed Tomography (CBCT) image of different devices and protocols for diagnosing periodontal structures and correlate the findings with the contrast-to-noise ratio (CNR). One dry dentate mandible was scanned by six CBCT devices: Accuitomo 3D 170, CS 9000, CS 9300, Eagle 3D, i-CAT Classic, and Orthophos XG 3D. All CBCT devices were adjusted to provide a spatial resolution closest to 0.2 mm, and a FOV height limited to less than 100 mm. Cross-sectional images were evaluated randomly. The buccal bone coverage, the periodontal ligament space and the amount of image noise were assessed. The statistics were calculated based on a logistic regression model with the significance level set at 5%. Protocols with large FOVs demonstrated significantly lower image quality. No statistical differences were found regarding buccal bone coverage between the CBCT devices. The CNR showed the highest value for the Accuitomo 60mm x 60mm HiFi 180°, followed by the Accuitomo 60mm x 60mm HiFi 360°, and lower values for the i-Cat Classic and Orthophos XG 3D devices. Most protocols studied presented good image quality in evaluating the buccal bone coverage and periodontal ligament space. However, the exam with the lowest FOV of the Accuitomo 60mm x 60mm HiFi 180° device showed superiority concerning the others. Keywords: Cone-Beam Computed Tomography. Technology, Radiologic. Radiography, Dental, Digital. Periodontics. ResumoA qualidade das imagens de tomografia computadorizada de feixe cônico (CBCT) é diretamente influenciada pelos protocolos de digitalização e visualização. Avaliar a qualidade subjetiva da imagem da Tomografia Computadorizada de Feixe Cone (CBCT) de diferentes aparelhos e protocolos para o diagnóstico de estruturas periodontais e correlacionar os achados com a razão contraste-ruído (RCR). Uma mandíbula dentada seca foi digitalizada por seis dispositivos CBCT: Accuitomo 3D 170, CS 9000, CS 9300, Eagle 3D, i-CAT Classic e Orthophos XG 3D. Todos os dispositivos CBCT foram ajustados para fornecer uma resolução espacial próxima a 0,2 mm e uma altura de FOV limitada a menos de 100 mm. Imagens transversais foram avaliadas aleatoriamente. A cobertura óssea vestibular, o espaço do ligamento periodontal e a quantidade de ruído da imagem foram avaliados. As estatísticas foram calculadas com base em um modelo de regressão logística com nível de significância de 5%. Protocolos com grandes FOVs demonstraram qualidade de imagem significativamente inferior. Não foram encontradas diferenças estatísticas em relação à cobertura óssea vestibular entre os dispositivos CBCT. O CNR apresentou o maior valor para o Accuitomo 60mm x 60mm HiFi 180°, seguido pelo Accuitomo 60mm x 60mm HiFi 360°, e valores menores para os dispositivos i-Cat Classic e Orthophos XG 3D. A maioria dos protocolos estudados apresentou boa qualidade de imagem na avaliação da cobertura óssea vestibular e do espaço do ligamento periodontal. Entretanto, o exame com menor FOV do aparelho Accuitomo 60mm x 60mm HiFi 180° apresentou superioridade em relação aos demais. Palavras-chave: Tomografia Computadorizada Cone-Beam. Tecnologia Radiológica. Radiografia Odontológica Digital. Periodontia

The effect of voxel and field of view size on the volumetric alteration artifact of high-density materials with 2 cone beam computed tomography devices

We investigated the influence of voxel and field of view (FOV) sizes on expression of the volumetric alteration artifact (VAA) of 5 high-density materials in 2 cone beam computed tomography (CBCT) devices. Cylinders of amalgam, cobalt-chromium, gutta-percha, titanium, and zirconium were individually positioned in a polymethyl methacrylate phantom. OP300 Maxio and ProMax 3D Classic CBCT devices were used to acquire images with varying voxel and FOV sizes, totaling 585 scans. Two evaluators segmented the high-density cylinder images to obtain the tomographic volumes. The difference between the tomographic and physical volume of each cylinder (i.e., volumetric alteration) was calculated. Statistical analysis was conducted with multiway ANOVA and the Tukey post hoc test (α = 5%). Evaluator reliability was measured with the intraclass correlation coefficient (ICC). All studied parameters and nearly all interactions influenced the VAA (P < .05). The post hoc test demonstrated less volumetric alteration for the smallest voxel sizes, 61 × 78 mm FOV, and gutta-percha for OP300, and for the smallest voxel sizes, 80 × 80 mm FOV, and gutta-percha and titanium for ProMax 3D (P < .05). The ICC demonstrated perfect reliability (1.00). Voxel and FOV sizes influenced VAA expression. Using smaller voxel sizes, the 61 × 78 mm FOV for OP300 and the 80 × 80 mm FOV for ProMax 3D, and materials with lower density and lower atomic number reduced VAA expression.

Scattered Radiation Distribution Utilizing Three Different Cone-Beam Computed Tomography Devices for Maxillofacial Diagnostics: A Research Study.

This study aimed to estimate scattered radiation and its spatial distribution around three cone-beam computed tomography (CBCT) devices, in order to determine potential positions for an operator to stand if they needed to be inside the CBCT room. The following devices were tested: Morita Accuitomo (CBCT1), Newtom Giano HR (CBCT2), Newtom VGi (CBCT3). Scattered radiation measurements were performed using different kVp, mA, and Field of View (FOV) options. An anthropomorphic phantom (NATHANIA) was placed inside the X-ray gantry to simulate clinical conditions. Scattered measurements were taken with the Inovision model 451P Victoreen ionization chamber once placed at fixed distances from each irradiation isocenter, away from the primary beam. A statistically significant (p < 0.001) difference was found in the mean value of the scattered radiation estimations between the CBCT devices. Scattered radiation was reduced with a different rate for each CBCT device as distance was increased. For CBCT1 the reduction was 0.047 μGy, for CBCT2 it was 0.036 μGy, and for CBCT3 it was 0.079 μGy, for every one meter from the X-ray gantry. Therefore, at certain distances from the central X-ray, the scattered radiation was below the critical level of 1 mGy, which is defined by the radiation protection guidelines as the exposure radiation limit of the general population. Consequently, an operator could stay inside the room accompanying the patient being scanned, if necessary.

Ex vivo detection of mandibular incisors’ root canal morphology using cone-beam computed tomography with 4 different voxel sizes and micro-computed tomography

BackgroundIn recent years, cone-beam computed tomography (CBCT) has been widely used to evaluate patients’ root canal anatomy due to its high resolution and noninvasive nature. As voxel size is one of the most important parameters affecting CBCT image quality, the current study evaluated the diagnostic potential of CBCT with 4 different voxel sizes in the detection of double root canal systems and accessory canals (ACs) in permanent mandibular incisors.MethodsA total of 106 extracted mandibular permanent incisors were collected from the dental clinics, and then were scanned by using micro-CT with a voxel size of 9 μm. The teeth were then fixed in the tooth sockets of human dry mandibles and scanned by using a CBCT device with 4 different voxel sizes (300, 200, 250, and 125 μm). Four observers detected in blind the root canal morphology of the teeth according to the CBCT images, and the presence or absence of a double root canal system, and the presence or absence of ACs, were scored according to a 5-point scale, respectively. Receiver operating characteristic (ROC) analysis was performed, and DeLong test was used to compare the area under the curve (AUC) values and the micro-CT data was taken as a gold standard.ResultsAmong 106 sample teeth, 25 specimens with a double root canal system were identified by the micro-CT. ROC curve analysis of the data obtained by the four observers showed that in the detection of double root canal systems, the AUC values ranged from 0.765 to 0.889 for 300 μm voxel size, from 0.877 to 0.926 for 250 μm voxel size, from 0.893 to 0.967 for 200 μm voxel size, and from 0.914 to 0.967 for 125 μm voxel size (all p < 0.01). In general, we observed a trend that the AUC values, sensitivity, and specialty increased with the decrease in the voxel size, and significantly higher AUC values were detected in 125 μm voxel size images. In the detection of ACs, ROC curve analysis showed that among the four observers, the AUC values ranged from 0.554 to 0.639 for 300 μm voxel size, from 0.532 to 0.654 for 250 μm voxel size, from 0.567 to 0.626 for 200 μm voxel size, and from 0.638 to 0.678 for 125 μm voxel size. CBCT images at a voxel size of 125 μm had a weak diagnostic potential (AUC: 0.5–0.7, all p < 0.05) in the detection of AC, with a lower sensitivity ranging from 36.8 to 57.9% and a higher specialty ranging from 73.6 to 98.8%.ConclusionsCBCT with 300 μm voxel size could only provide moderate diagnostic accuracy in the detection of a double canal system in mandibular incisors. CBCT with a voxel size of 125 μm exhibited high diagnostic value in the detection of double canal systems, while showing low but statistically significant value in the detection of ACs.

Zirconia implants interfere with the evaluation of peri-implant bone defects in cone beam computed tomography (CBCT) images even with artifact reduction, a pilot study.

Three-dimensional cone beam computed tomography (CBCT) imaging can be considered, especially in patients with complicated peri-implantitis (PI). Artifacts induced by dense materials are the drawback of CBCT imaging and the peri-implant bone condition may not be assessed reliably because the artifacts are present in the same area. This pilot study investigates the performance of the artifact reduction algorithm (ARA) of the Planmeca Viso G7 CBCT device (Planmeca, Helsinki, Finland) with three different implant materials and imaging parameters. Three pairs of dental implants consisting of titanium, zirconia, and fiber reinforced composite (FRC) were set into a pig mandible. A vertical defect simulating peri-implantitis bone loss was made on the buccal side of one of each implant. The defect was identified and measured by two observers and compared to the actual dimensions. In addition, the bone structure and the marginal cortex visibility between the implants were estimated visually. The bone defect and its dimensions with the zirconia implant could not be identified in any image with or without the metal artifact reduction algorithm. The bone defect of titanium and FRC implants were identified with all three imaging parameters or even without ARA. The interobserver agreement between the two observers was almost perfect for all categories analyzed. Peri-implantitis defect of the zirconia implant and the peri-implant bone structure of the zirconia implants cannot be recognized reliably with any ARA levels, or any imaging parameters used with the Planmeca Viso G7. The need for ARA when imaging the peri-implant bone condition of the titanium and FRC implants may be unnecessary.

Does the shape of the field-of-view influence the magnitude of artefacts from high-density materials in cone-beam computed tomography?

To compare cylindrical and convex triangular field-of-views (FOVs) concerning the magnitude of artefacts from high-density materials in cone-beam CT (CBCT). Cylinders of amalgam, chromium-cobalt, titanium, and zirconia were individually placed in the anterior and posterior regions of a polymethylmethacrylate phantom and scanned using cylindrical and convex triangular FOVs of the Veraview X800 CBCT device. Using the Image J software, 15 square regions of interest (ROIs) were placed in the axial reconstruction around the middle level of the cylinder and at distances of 0.5, 1.0, and 1.5 cm from the centre of the cylinder. Mean grey value and standard deviation of each ROI were averaged for each distance and subtracted from the values of a control ROI to calculate the magnitude of the artefacts by the grey value mean difference (GVMD) and grey value standard deviation (GVSD). Multiway analysis of variance with Tukey post-hoc test with a significance level of 5% evaluated the effect of the shape of the FOV, position inside the FOV, high-density material, and the distance of the artefact from the material. The convex triangular FOV increased the GVSD for all materials in the anterior and posterior regions at 0.5 cm compared to the cylindrical FOV (p < 0.0001). The convex triangular FOV showed greater GVMD for chromium-cobalt and zirconium in the anterior region and all materials in the posterior region at all distances (p < 0.0001). The FOV shape influences the magnitude of artefacts from high-density materials. The convex triangular FOV showed greater artefact magnitude with variability among the high-density materials, region in the FOV, and distance from the material.

Comparison of artifact values of prosthodontic materials with 2 different cone beam computed tomography devices

Statement of problemProsthodontic materials may cause unexpected artifacts in cone beam computed tomography (CBCT) images, but studies quantifying these artifacts are sparse. PurposeThe purpose of this in vitro study was to compare the artifact expression of fixed prosthodontic materials with different CBCT devices. Material and methodsTen prosthodontic materials (Co-Cr-Mo alloy, interim acrylic resin, polyetheretherketone, feldspathic ceramic, lithium disilicate glass-ceramic, zirconia-reinforced lithium silicate ceramic, zircon core, and 3 monolithic zirconias) were scanned with 2 CBCT devices. The materials were placed in polymethyl methacrylate resin to simulate clinical conditions. To assess the impact of the devices on artifacts, the gray values of 8 areas in each material image were analyzed. The data were analyzed with the Kruskal-Wallis and Wilcoxon Signed-Rank tests (α=.05). ResultsStatistically significant differences were found in the artifact expression of the materials (P<.001) and between CBCT devices (P<.001). ConclusionsThe artifact expression of polymeric and ceramic materials in CBCT images was less than that of other materials. The milliampere-second (mAs) value of CBCT devices had a significant impact on the artifact level.

IMPLICATIONS OF CBCT IN PEDIATRIC DENTISTRY-A REVIEW

The introduction of CBCT(Cone Beam Computed Tomography) devices, modified the way dentistry is practiced. CBCT was encircled into dentistry very expeditiously due to its low cost, compact size, low ionizing radiation exposure. CBCT with 3D (Three dimensional) technology is a replacement for conventional 2D (Two dimensional) imaging &amp; has a wide application among child patients in pediatric dentistry. This article provides an overview of basics of CBCT technology &amp; reviews the specific implications of CBCT technology to pediatric &amp; preventive dentistry.

Accuracy of CAD-CAM Surgically Guided Tooth Autotransplantation Using Guided Templates and Custom-designed Osteotomes in Human Cadaver Mandibles

IntroductionA major challenge in dentistry is the replacement of teeth lost prematurely due to trauma, caries, or malformations; especially in growing patients. The aim of this study was to assess the accuracy of CAD-CAM surgically guided tooth autotransplantation in cryopreserved cadaver mandibles using guided templates and custom-designed osteotomes. MethodsCryopreserved human cadaver heads were digitized and scanned using an intraoral optical scanner and a large-volume cone beam computed tomography device. First, virtual surgical planning was performed to create a 3D tooth replica, 2 surgical guides, and a custom-made osteotome for each single-rooted tooth autotransplantation procedure/case. Surgical sockets were created in the selected mandibles using guided tooling consisting of an initial guided osteotomy with implant burs and a final guided osteotomy using custom osteotomes. After tooth autotransplantation, second large-volume cone beam computed tomography images of the 5 cadaver mandibles were obtained. The discrepancy in mm within the 3D space (apical and mesiodistal deviations) between the final position of the autotransplanted teeth and their digitally planned 3D initial position was calculated and analyzed statistically (P < .05). ResultsAll donor teeth were placed without incident within their newly created sockets in the real mandibles. The mean difference between the digitally planned root apex position and the final tooth position was 2.46 ± 1.25 mm. The mesiodistal deviation of the autotransplanted teeth was 1.63 ± 0.96 mm. ConclusionsThe autotransplantation of single-rooted teeth with custom-designed and 3D-printed surgical tooling provided promising results. The technique was able to create surgically prepared sockets that could accommodate transplanted teeth in mandibles.

Deep learning for detection and 3D segmentation of maxillofacial bone lesions in cone beam CT.

To develop an automated deep-learning algorithm for detection and 3D segmentation of incidental bone lesions in maxillofacial CBCT scans. The dataset included 82 cone beam CT (CBCT) scans, 41 with histologically confirmed benign bone lesions (BL) and 41 control scans (without lesions), obtained using three CBCT devices with diverse imaging protocols. Lesions were marked in all axial slices by experienced maxillofacial radiologists. All cases were divided into sub-datasets: training (20,214 axial images), validation (4530 axial images), and testing (6795 axial images). A Mask-RCNN algorithm segmented the bone lesions in each axial slice. Analysis of sequential slices was used for improving the Mask-RCNN performance and classifying each CBCT scan as containing bone lesions or not. Finally, the algorithm generated 3D segmentations of the lesions and calculated their volumes. The algorithm correctly classified all CBCT cases as containing bone lesions or not, with an accuracy of 100%. The algorithm detected the bone lesion in axial images with high sensitivity (95.9%) and high precision (98.9%) with an average dice coefficient of 83.5%. The developed algorithm detected and segmented bone lesions in CBCT scans with high accuracy and may serve as a computerized tool for detecting incidental bone lesions in CBCT imaging. Our novel deep-learning algorithm detects incidental hypodense bone lesions in cone beam CT scans, using various imaging devices and protocols. This algorithm may reduce patients' morbidity and mortality, particularly since currently, cone beam CT interpretation is not always preformed. • A deep learning algorithm was developed for automatic detection and 3D segmentation of various maxillofacial bone lesions in CBCT scans, irrespective of the CBCT device or the scanning protocol. • The developed algorithm can detect incidental jaw lesions with high accuracy, generates a 3D segmentation of the lesion, and calculates the lesion volume.