Cone-beam Computed Tomography Data Research Articles

Key insights into antiresorptive drug use and osteonecrosis in osteoporotic patients undergoing tooth extractions: A clinical and CBCT assessment.

To describe the effects of antiresorptive drugs (ARD) in the maxilla and mandible and risk factors for medication-related osteonecrosis of the jaws (MRONJ) in osteoporotic patients undergoing tooth extractions using clinical data and cone beam computed tomography (CBCT). This retrospective cohort study collected clinical and CBCT data from 176 patients. The study group (n = 78; 224 extractions) received ARD treatment, underwent tooth extraction, and had a pre-operative CBCT. Additionally, age-, sex-, and tooth-matched controls were selected (n = 98; 227 extractions). Radiographic examinations were performed independently by three calibrated examiners. Statistical analysis included Chi-square, Fisher's exact, Mann-Whitney U, and t-tests to contrast clinical and radiographic data between study and control, MRONJ + and MRONJ - , and bisphosphonate and denosumab patients/sites. Significance was set at p ≤ 0.05. From the study group, 4 patients (5%) and 5 sites (2%) developed MRONJ after tooth extraction. ARD-treated patients exhibited significantly more thickening of the lamina dura and a longer average mucosal healing time (4.4weeks) than controls (2.6weeks). In the study group, MRONJ risk significantly increased with corticosteroid intake and in multi-rooted teeth. No significant differences between bisphosphonates and denosumab use were seen in the tomographic features (p > 0.05). Lastly, bone sequestrum was exclusively observed in osteoporotic patients, who exhibited post-operative exposed bone or histological evidence of osteonecrosis. Osteoporotic patients under ARD may exhibit thickening of the lamina dura and prolonged post-operative healing. Among these patients, multi-rooted teeth are at higher risk for MRONJ than single-rooted teeth. Sequester formation is a radiographic indicator of osteonecrosis.

Digital Planning to Enhance Diagnosis and Precision in Correcting Excessive Gingival Display in the Presence of Asymmetrical Maxillary Position: A Case Report.

This case report addresses the treatment of excessive gingival display (EGD) in the context of maxillary asymmetry, zenith irregularities, and occlusal plane inclination. Digital planning was pivotal in formulating a precise treatment strategy by incorporating facial photographs, digital models, and cone-beam computed tomography data. Parameters, including occlusal plane inclination, teeth position, and lip-to-gingival margin relationships, were considered to ensure treatment alignment with the patient's facial characteristics. Notably, during the planning phase, it was evident that the conventional approach using the cementoenamel junction as the apical limit for incisions would result in asymmetry. Consequently, the gingival margin position was defined in accordance with facial and lip features. The chosen treatment, flapless crown lengthening, was tailored to the patient's thin phenotype and guided by measurements derived from digital planning. Postsurgery, the patient experienced a swift and painless recovery. A harmonious smile with a stable gingival margin position was achieved at the 1-year follow-up, seamlessly complementing the patient's facial attributes. This case underscores the importance of personalized EGD treatment and the value of digital planning in enhancing diagnostic accuracy and precise treatment planning, ultimately facilitating optimal treatment strategies.

Anatomic considerations during placement of mandibular retromolar miniplates for orthodontic anchorage – A study of the characteristics of retromolar fossa

Objectives: The mandibular retromolar area offers a novel site for orthodontic skeletal anchorage. It houses the retromolar foramen (RMF), and surgical interventions in this area can lead to undesirable outcomes. This study aims to assess the characteristics of the RMF and its relation to the occlusal plane (OP) using cone-beam computed tomography (CBCT) data. Material and Methods: This cross-sectional observational in vitro study involved the analysis of CBCT data from 136 samples (68 males and 68 females) within the age range of 18–40 years. The study focused on factors such as the presence or absence of the RMF, whether it was unilateral or bilateral, the number of foramina on each side, and the distance of the RMF from the OP. Data analysis was conducted using the Statistical Package for the Social Sciences software, with P < 0.05 deemed statistically significant at a 95% confidence level. Results: About 39% of the sample showed the presence of RMF. The prevalence of unilateral RMF was higher than that of bilateral RMF. The mean distance of RMF above the OP was 5.99 mm, and that below the OP was 3.82 mm. Conclusion: The high prevalence (39%) of RMF suggests that the retromolar fossa region should be evaluated before the placement of mini-plates. The prevalence of RMF above the OP was significantly higher than that below the OP.

A randomized controlled clinical trial of concentrated growth factor combined with sodium hyaluronate in the treatment of temporomandibular joint osteoarthritis

ObjectiveTo investigate the effect of concentrated growth factor (CGF) combined with sodium hyaluronate (SH) on temporomandibular joint osteoarthritis (TMJOA).MethodsSixty patients with TMJOA who were diagnosed by cone-beam computed tomography (CBCT) between March 2020 and March 2023 at the Stomatological Hospital of Xi’an Jiaotong University were randomly divided into a control group (n = 30) and an experimental group (n = 30). The patients in the experimental group were treated with CGF + SH, and those in the control group were treated with SH only. The visual analogue scale (VAS) score indicating pain in the temporomandibular joint (TMJ) area; the Helkimo Clinical Dysfunction Index (Di); and changes in condylar CBCT at the first visit and 2 weeks, 3 months and 6 months after treatment were recorded. The CBCT data of the patients in the experimental and control groups were collected, and the three-dimensional CBCT image sequences were imported into Mimics Medical 19.0 software in DICOM format for condylar reconstruction.ResultsThe VAS scores at 2 weeks, 3 months and 6 months after treatment were significantly lower in the experimental group than in the control group (P < 0.05), and the pain in the experimental group was significantly relieved. The Di was significantly lower in the experimental group than in the control group (P < 0.05), and the clinical function of the TMJ improved. After treatment, the CBCT score was significantly lower in the experimental group than in the control group (P < 0.05), and the condylar bone cortex was obviously repaired. Observation of the condylar bone cortex by three-dimensional reconstruction showed the same results as those obtained by CBCT.ConclusionCGF combined with SH is effective in the treatment of TMJOA and can improve muscle pain, TMJ pain, Impaired TMJ function, Impaired range of movement, Pain on movement of the mandible and promote bone repair.The registration number (TRN)ChiCTR2400082712.The date of registrationApril 5, 2024.

Measurement of mandibular incisive canal diameter using cone beam computed tomography

Cone beam computed tomography was used for measuring the diameter of a Mandibular incisive canal. The dental practice can now visualize small bone structures with low dose and high spatial resolution due to the introduction of CBCT (Cone Beam Computed Tomography). Therefore, it is of interest to measure the diameter of the MIC (Mandibular Incisive Canal) using the CBCT. Fifty CBCT scans obtained for implant placement preoperative planning were included in the study material. Observers carefully examined the CBCT data to determine the MIC’s presence &amp; position. The inner diameter of the MIC was measured by taking the longest distance between the inner cortical borders of the canal which was further analyzed using software CS3D software. The collected data were further subjected to statistical analysis. The average mean of the population was 1.7130±.5178. The average diameter of MIC in males was 1.735±.5406 and in females was 1.6800±.4934. Complications from implant surgery in the anterior mandible may be prevented by utilizing CBCT scans to analyze the smallest diameter of the MIC.

Effects of adenoid hypertrophy on nasopharyngeal airway ventilation: A computational fluid dynamics study

ObjectivesAdenoid hypertrophy causes impaired nasopharyngeal airways (NA) ventilation. However, it is difficult to evaluate the ventilatory conditions of NA. Therefore, this study aimed to analyze the nasopharyngeal airway resistance (NARES) based on computational fluid dynamics simulations and the nasopharyngeal airway depth (NAD) and adenoid hypertrophy grade measured on cephalometric cone-beam computed tomography images and determine the relationship between NAD and grade and NARES to ultimately assess using cephalometric measurements whether NA has airway obstruction defects. MethodsCephalogram images were generated from cone-beam computed tomography data of 102 children (41 boys; mean age: 9.14 ± 1.43 years) who received orthodontic examinations at an orthodontic clinic from September 2012 to March 2023, and NAD and adenoid grade and NARES values were measured based on computational fluid dynamics analyses using a 3D NA model. Nonlinear regression analyses were used to evaluate the relationship between NARES and NAD and correlation coefficients to evaluate the relationship between grade and NARES. ResultsNARES was inversely proportional to the cube of NAD (R2 = 0.786, P < 0.001), indicating a significant relationship between these variables. The resistance NARES increased substantially when the distance NAD was less than 5 mm. However, adenoid Grade 4 (75 % hypertrophy) was widely distributed. ConclusionsThese study findings demonstrate that the ventilatory conditions of NA can be determined based on a simple evaluation of cephalogram images. An NAD of less than 5 mm on cephalometric images results in NA obstruction with substantially increased airflow resistance.

Cone beam computed tomography assessment of maxillary anterior teeth cervix dimensions in healthy adults for optimal anatomic healing abutments.

The abutments produced with circular symmetry failed to accurately replicate the natural teeth's cervical shapes. The purpose of this study was to measure cervical cross-sections of maxillary anterior teeth using cone beam computed tomography (CBCT) images to design anatomic healing abutments. CBCT data of 61 patients were analyzed using Ez3D Plus software. Measurements were taken at the cemento-enamel junction (CEJ) and 1 mm coronal to CEJ for maxillary central incisors, lateral incisors, and canines. Various parameters, including area, perimeter, and eight line segments in the distal (a), disto-palatal (b), palatal (c), mesio-palatal (d), mesial (e), mesio-labial (f), labial (g), and disto-labial (h) directions, were used to describe dental neck contours. The ratios (f/b and h/d) were analyzed, and differences based on sex and dental arch morphology were explored. Significant differences were found in area and perimeter between males and females, but not in f/b and h/d ratios. Differences in the f/b ratio were observed among dental arch morphologies for maxillary central incisors, lateral incisors, and canines. CBCT measurements of cervical cross-sections provide more accurate data for designing anatomic healing abutments. The fabrication of anatomical healing abutments needs to consider the influence of gender on cervical size and to explore the potential effect of arch shape on cervical morphology. The novel method provides detailed measurements for the description of dental cervical contours for patients with bilateral homonymous teeth missing. The measurements of this study could be utilized to design more accurate anatomic healing abutments to create desired morphology of peri-implant soft tissue.

Create virtual dentoskeletal model by superimposing digital dental cast into cone-beam computed tomography scan.

Many artifacts and obstacles associated with cone-beam computed tomography (CBCT) scan can obscure or distort the details of the teeth and occlusal surface, like distorted teeth, streak artifacts, noise, and some malocclusion cases with excessive overlapping between jaws cause decrease the interocclusal space, which can impact diagnosis and treatment planning, and the 3D reconstruction accuracy. Optimizing dental precision by Integrating CBCT scans with other imaging modalities, supply more information to enhance CBCT accuracy, mainly in dental areas with limited clarity. Performing the Structure-from-Motion (SfM) photogrammetry method, using phone camera and photograph studio setup using simple hardware, to digitize the dental casts and obtain an accurate digital dental model. Using this digital dental model to enhance dental precision in the CBCT data by performing the superimposition process, using a surface-based registration method and integration process to create a virtual dentoskeletal model. Evaluate the accuracy and quality of the superimposition results using qualitative (visual inspection) and quantitative measures. The differences between the virtual dentoskeletal model and the reference CBCT model are calculating by the 3D Euclidean distance, the mean ± SD are 0.212 ± 0.169mm and 0.26 ± 0.149mm for the maxilla and mandible, respectively. The color-coded map shows that the two surfaces are similar, but the extremist values are concentrated in the dental region due to the presence of the noise in the reference model and the gingiva in the virtual dentoskeletal model. The resulting virtual dentoskeletal model can be viewed and manipulated on a computer screen, allowing for a detailed analysis of the teeth and supporting structures. The 3D model generated by the SfM photogrammetry technique did well during the superimposition process, representing a reliable method for virtual-based processing such as orthognathic surgery planning and splint design.

230 Machine Learning for Automated and Real-time 2D-3D Registration of the Spine Using Only a Single Radiograph

INTRODUCTION: Authors present a 2-dimensional to 3-dimensional (2D-3D) registration algorithm that identifies the position of a C-arm relative to a 3D volume. METHODS: This work utilizes digitally reconstructed radiographs (DRR) which are synthetic radiographic images generated by simulating the x-ray projections as they would pass through a CT volume. To evaluate our algorithm, we used cone-beam CT data from 127 patients obtained from a de-identified registry of cervical, thoracic, and lumbar scans. We systematically evaluated and tuned a self-supervised algorithm, quantified the limitations and convergence rate of our model by simulating C-arm registrations with 80 randomly simulated DRRs for each CT volume. The endpoints for this study were the time to convergence, accuracy of convergence for each of the C-arm's degrees of freedom (DoF), and overall registration accuracy based on a voxel-by-voxel measurement. RESULTS: 10,160 unique fluoroscopic images were simulated from 127 CT scans. Our algorithm successfully converged to the correct solution 81% of the time with an average of 1.97 seconds of computation. The fluoroscopic images for which the algorithm converged to the solution achieved 99.9% registration accuracy despite only utilizing single-precision computation for speed. Our algorithm was found to be optimized for convergence when the search space was limited to a ± 45° offset in the RAO/LAO, cranial/caudal and receiver rotation angles with the radiographic isocenter contained within 8000cm3 of the volumetric center of the CT volume. CONCLUSIONS: The machine learning algorithm we present has the potential to aid surgeons with many aspects of spine surgery through an automated 2D-3D registration process. Future work will focus on algorithmic optimizations adn deep-learning to improve the convergence rate and speed profile.

Cone-beam CT-based Navigation With Augmented Fluoroscopy of the Airways for Image-guided Bronchoscopic Biopsy of Peripheral Pulmonary Nodules: A Prospective Clinical Study.

Cone-beam computed tomography (CBCT) and augmented fluoroscopy (AF), in which intraprocedural CBCT data is fused with fluoroscopy, have been utilized as a novel image-guidance technique for biopsy of peripheral pulmonary lesions. The aim of this clinical study is to determine the safety and diagnostic performance of CBCT-guided bronchoscopy with advanced software tools for procedural planning and navigational guidance with AF of the airways for biopsy of peripheral pulmonary nodules. Fifty-two consecutive subjects were prospectively enrolled in the AIRWAZE study (December 2018 to October 2019). Image-guided bronchoscopic biopsy procedures were performed under general anesthesia with specific ventilation protocols in a hybrid operating room equipped with a ceiling-mounted C-arm system. Procedural planning and image-guided bronchoscopy with CBCT and AF were performed using the Airwaze investigational device. A total of 58 pulmonary lesions with a median size of 19.0mm (range 7 to 48mm) were biopsied. The overall diagnostic yield at index procedure was 87.9% (95% CI: 77.1%-94.0%). No severe adverse events related to CBCT-guided bronchoscopy, such as pneumothorax, bleeding, or respiratory failure, were observed. CBCT-guided bronchoscopic biopsy with augmented fluoroscopic views of the airways and target lesion for navigational guidance is technically feasible and safe. Three-dimensional image-guided navigation biopsy is associated with high navigational success and a high diagnostic yield for peripheral pulmonary nodules.

Results of bone grafting using a xenogenic cortical plate BiOTECK

BACKGROUND: The fundamental condition that determines the effectiveness of treatment, with immediate and long-term positive results, is the amount of bone tissue in the jaws at the proposed implantation site. Defects in the dentition to a large extent and severe atrophy of the bone tissue of the jaws due to the loss of teeth significantly limit the use of dental implantation. It is reasonable to expand the indications for the use of dental implants in cases of atrophy of the jaw bone tissue in the installation site. This allows the optimization of surgical techniques aimed at increasing the volume of the jaw bone tissue, such as the use of new osteoplastic materials for guided bone regeneration.&#x0D; AIM: This study aimed to analyze the results of a jawbone graft using a BiOTECK xenogeneic cortical plate.&#x0D; MATERIALS AND METHODS: The test group consisted of 22 patients (11 men and 11 women) with jawbone atrophy. All patients underwent bone graft surgery using a BiOTECK xenogeneic cortical plate (BiOTECK, Italy).&#x0D; In the course of the study, all patients with jawbone loss underwent a dynamic clinical and X-ray examination during the following stages: during the dental implant surgery planning stage aimed at determining the volume of the bone tissue available and identifying the associated conditions and diseases (prior to conducting an osteoplastic procedure), prior to dental implant installation (6 months after osteoplastic surgery), and prior to the start of the orthopedic stage of treatment (12 months after osteoplastic surgery).&#x0D; RESULTS: The cone beam computed tomography data were analyzed and statistically processed to obtain the results. It was revealed that the values of the “bone densitometry” indicator increased 6 months after the bone graft using the BiOTECK xenogeneic cortical plate, and the values of the “densitometric density of jaw bone tissue” indicator increased.&#x0D; Immediately after bone grafting using the BiOTECK xenogeneic cortical plate, the thickness of the bone tissue of the upper jaw increased by an average of 5.0±0.1 mm and that of the lower jaw increased by an average of 3.9±0.1 mm. In the first stage of the dental implant surgery (6 months after osteoplastic procedure), due to resorption, the thickness of the bone tissue of the alveolar process of the upper jaw decreased by 1.1±0.1 mm and amounted to 6.8±0.1 mm (bone resorption rate: 13.9%), and the thickness of the bone tissue of the alveolar process of the lower jaw decreased by 0.8±0.2 mm and amounted to 6.6±0.3 mm (bone resorption rate: 10.3%).&#x0D; CONCLUSION: The clinical and X-ray results obtained 1 year after installing dental implants and performing bone graft surgery using the BiOTECK xenogeneic cortical plate indicate a stable volume of marginal bone tissue in the area of alveolar crest reconstruction.

Clinical challenges of biomechanical performance of narrow-diameter implants in maxillary posterior teeth in aging patients: A finite element analysis.

This study evaluated the biomechanical performance of narrow-diameter implant (NDI) treatment in atrophic maxillary posterior teeth in aging patients by finite element analysis. The upper left posterior bone segment with first and second premolar teeth missing obtained from a patient's cone beam computed tomography data was simulated with cortical bone thicknesses of 0.5 and 1.0 mm. Three model groups were analyzed. The Regimen group had NDIs of 3.3 × 10 mm in length with non-splinted crowns. Experimental-1 group had NDIs of 3.0 × 10 mm in length with non-splinted crowns and Experimental-2 group had NDIs of 3.0 × 10 mm in length with splinted crowns. The applied load was 56.9 N in three directions: axial (along the implant axis), oblique at 30° (30° to the bucco-palatal plane compared to the vertical axis of the tooth), and lateral load at 90° (90° in the bucco-palatal plane compared to the vertical axis of the tooth). The results of the von Mises stress on the implant fixture, the elastic strain, and principal value of stress on the crestal marginal bone were analyzed. The axial load direction was comparable in the von Mises stress values in all groups, which indicated it was not necessary to use splinted crowns. The elastic strain values in the axial and oblique directions were within the limits of Frost's mechanostat theory. The principal value of stress in all groups were under the threshold of the compressive stress and tensile strength of cortical bone. In the oblique and lateral directions, the splinted crown showed better results for both the von Mises stress, elastic strain, and principal value of stress than the non-splinted crown. In conclusion, category 2 NDIs can be used in the upper premolar region of aging patients in the case of insufficient bone for category 3 NDI restorations.

Cone-beam computed tomography of accessory canals of the canalis sinuosus and analysis of the related risk factors.

Cone-beam computed tomography (CBCT) was used in this study for evaluating the diameter, prevalence, spatial location, and risk factors of the accessory canal (AC) of the canalis sinuosus. A comprehensive assessment of the incidence rate, diameter, three-dimensional (3D) spatial location, and direction of travel of AC was performed on 1003 CBCT images. The CBCT data were used to reconstruct a 3D model of the maxilla to determine the alveolar bone volume. The obtained data were further analyzed and processed. AC was present in 50.1% of images. Male patients more frequently had ACs than female patients did (P < 0.01) and was positively correlated with the maxillary alveolar bone volume (P < 0.001, OR 1.532). Age or nasopalatine canal diameter were not significantly associated with the occurrence of AC (P > 0.05). Among the 502 patients with AC, AC was present on the left side, right side, and bilaterally in 189, 98, and 215, respectively. The maximum number of ACs observed per individual was eight. The average AC diameter was 0.89 ± 0.26mm (minimum, 0.5mm; maximum, 2.02mm). As the prevalence of AC and its trajectory display considerable variation among individuals, surgeons must consider the possibility of the presence of AC when devising surgical plans involving the anterior maxillary region.

Digital registration versus cone-beam computed tomography for evaluating implant position: a prospective cohort study

BackgroundPostoperative cone-beam computed tomography (CBCT) examination is considered a reliable method for clinicians to assess the positions of implants. Nevertheless, CBCT has drawbacks involving radiation exposure and high costs. Moreover, the image quality can be affected by artifacts. Recently, some literature has mentioned a digital registration method (DRM) as an alternative to CBCT for evaluating implant positions. The aim of this clinical study was to verify the accuracy of the DRM compared to CBCT scans in postoperative implant positioning.Materials and methodsA total of 36 patients who received anterior maxillary implants were included in this clinical study, involving a total of 48 implants. The study included 24 patients in the single implant group and 12 patients in the dual implant group. The postoperative three-dimensional (3D) positions of implants were obtained using both CBCT and DRM. The DRM included three main steps. Firstly, the postoperative 3D data of the dentition and intraoral scan body (ISB) was obtained through the intraoral scan (IOS). Secondly, a virtual model named registration unit which comprised an implant replica and a matching ISB was created with the help of a lab scanner and reverse engineering software. Thirdly, by superimposing the registration unit and IOS data, the postoperative position of the implant was determined. The accuracy of DRM was evaluated by calculating the Root Mean Square (RMS) values after superimposing the implant positions obtained from DRM with those from postoperative CBCT. The accuracy of DRM was compared between the single implant group and the dual implant group using independent sample t-tests. The superimposition deviations of CBCT and IOS were also evaluated.ResultsThe overall mean RMS was 0.29 ± 0.05 mm. The mean RMS was 0.30 ± 0.03 mm in the single implant group and 0.29 ± 0.06 mm in the dual implant group, with no significant difference (p = 0.27). The overall registration accuracy of the IOS and CBCT data ranged from 0.14 ± 0.05 mm to 0.21 ± 0.08 mm.ConclusionIn comparison with the 3D implant positions obtained by CBCT, the implant positions located by the DRM showed clinically acceptable deviation ranges. This method can be used in single and dual implant treatments to assess the implant positions.

Comparison of the impact of orthodontic treatment on pulp volume in adolescents and adults

Objective: To compare the impact of orthodontic treatment on pulp volume in adolescents and adults. Methods: Cone-beam CT data of 62 patients undergoing orthodontic treatment at the Department of Orthodontics, Stomatological Hospital of Chongqing Medical University, from January 2019 to March 2022 were collected. Patients were divided into two age groups (31 patients in each group): adolescent group (aged 13-17, 17 males and 14 females) and adult group (aged 21-25, 12 males and 19 females). Pre-and post-treatment reconstructions of the pulp and dental tissues of upper first molars (UM1) and lower central incisors (L1) were performed. Measurements included pulp volume for UM1 (UM1 P) and L1 (L1 P), pulp chamber volume (UM1 PC) and root canal volume (UM1 RC) for UM1, root length for L1 (L1 RL), and mesiobuccal root length for UM1 (UM1 RL), as well as chamber heights at specific landmarks [the lengths from the central fossa fusion site to the roof of the pulp chamber (H1), the floor of the pulp chamber (H2), the nearest point of root divergence as well as crown-root bifurcation (H3), the farthest point of root divergence (H4), and the pulp chamber height (H5)] in UM1. Changes in these indices were calculated and analyzed using paired and independent sample t-tests for within-group and between-group differences, respectively. Pearson correlation was used to assess potential associations among H5, root length, and pulp volume changes. Results: Before and after orthodontic treatment, no significant difference was observed in the adult group for L1 P (t=-0.03, P=0.975), while significant differences were noted for UM1 P, UM1 PC, and UM1 RC (t=9.98, P<0.001; t=9.04, P<0.001; t=6.69, P<0.001). In the adolescent group, significant differences were found for both L1 P and UM1 P (t=2.25, P=0.029; t=6.30, P<0.001). After orthodontic treatment, the absolute value changes of UM1 P, UM1 PC, and L1 P in the adolescent group were (19.75±9.58), (15.07±7.65) and (1.89±6.29) mm3, respectively, and in the adult group were (13.33±9.41), (9.16±7.05) and (0.02±4.66) mm3, respectively (t=3.77, P<0.001; t=4.48, P<0.001; t=2.34, P=0.048). There was no significant absolute difference in the amount of UM1 RC between the two groups after orthodontic treatment (t=0.86, P=0.391). Before and after orthodontic treatment, the absolute value changes of L1 RL, H1 and H5 in the adolescent group were (0.54±0.41), (0.38±0.27) and (0.71±0.33) mm, respectively, and the absolute value changes in the adult group were (0.78±0.62), (0.26±0.20) and (0.57±0.28) mm, respectively (t=-2.43, P=0.017; t=2.96, P=0.004; t=2.57, P=0.011). Whereas no significant differences were observed for UM1 RL, H2, H3, and H4 (t=-0.85, P=0.400; t=0.43, P=0.669; t=-0.50, P=0.619; t=1.46, P=0.148). Additionally, significant correlations were found between changes in H5 and UM1 RL with UM1 P (r=0.35, P<0.001; r=0.19, P=0.030), but not between Changes in L1 RL and L1 P (r=0.11, P>0.05). Conclusions: The effect of orthodontic treatment on pulp volume in adolescents and adults were different.

Feasibility of bone marrow edema detection using dual-energy cone-beam computed tomography.

Dual-energy (DE) detection of bone marrow edema (BME) would be a valuable new diagnostic capability for the emerging orthopedic cone-beam computed tomography (CBCT) systems. However, this imaging task is inherently challenging because of the narrow energy separation between water (edematous fluid) and fat (health yellow marrow), requiring precise artifact correction and dedicated material decomposition approaches. We investigate the feasibility of BME assessment using kV-switching DE CBCT with a comprehensive CBCT artifact correction framework and a two-stage projection- and image-domain three-material decomposition algorithm. DE CBCT projections of quantitative BME phantoms (water containers 100-165mm in size with inserts presenting various degrees of edema) and an animal cadaver model of BME were acquired on a CBCT test bench emulating the standard wrist imaging configuration of a Multitom Rax twin robotic x-ray system. The slow kV-switching scan protocol involved a 60kV low energy (LE) beam and a 120kV high energy (HE) beam switched every 0.5° over a 200° angular span. The DE CBCT data preprocessing and artifact correction framework consisted of (i) projection interpolation onto matched LE and HE projections views, (ii) lag and glare deconvolutions, and (iii) efficient Monte Carlo (MC)-based scatter correction. Virtual non-calcium (VNCa) images for BME detection were then generated by projection-domain decomposition into an Aluminium (Al) and polyethylene basis set (to remove beam hardening) followed by three-material image-domain decomposition into water, Ca, and fat. Feasibility of BME detection was quantified in terms of VNCa image contrast and receiver operating characteristic (ROC) curves. Robustness to object size, position in the field of view (FOV) and beam collimation (varied 20-160mm) was investigated. The MC-based scatter correction delivered>69% reduction of cupping artifacts for moderate to wide collimations (>80mm beam width), which was essential to achieve accurate DE material decomposition. In a forearm-sized object, a 20% increase in water concentration (edema) of a trabecular bone-mimicking mixture presented as ∼15 HU VNCa contrast using 80-160mm beam collimations. The variability with respect to object position in the FOV was modest (<15% coefficient of variation). The areas under the ROC curve were>0.9. A femur-sized object presented a somewhat more challenging task, resulting in increased sensitivity to object positioning at 160mm collimation. In animal cadaver specimens, areas of VNCa enhancement consistent with BME were observed in DE CBCT images in regions of MRI-confirmed edema. Our results indicate that the proposed artifact correction and material decomposition pipeline can overcome the challenges of scatter and limited spectral separation to achieve relatively accurate and sensitive BME detection in DE CBCT. This study provides an important baseline for clinical translation of musculoskeletal DE CBCT to quantitative, point-of-care bone health assessment.

The accuracy and reliability of different midsagittal planes in the symmetry assessment using cone-beam computed tomography.

Symmetry is an essential component of esthetic assessment. Accurate assessment of facial symmetry is critical to the treatment plan of orthognathic surgery and orthodontic treatment. However, there is no internationally accepted midsagittal plane (MSP) for orthodontists and orthognathic surgeons. The purpose of this study was to explore a clinically friendly MSP, which is more accurate and reliable than what is commonly used in symmetry assessment. Forty patients with symmetric craniofacial structures were analyzed on cone-beam computed tomography (CBCT) scans. The CBCT data were exported to the Simplant Pro software to build four reference planes that were constructed by nasion (N), basion (Ba), sella (S), odontoid (Dent), or incisive foramen (IF). A total of 31 landmarks were located to determine which reference plane is the most optimal MSP by comparing the asymmetry index (AI). The mean value of AI showed a significant difference (p < 0.05) among four reference planes. Also, the mean value of AI for all landmarks showed that Plane 2 (consisting of N, Ba, and IF) and Plane 4 (consisting of N, IF, and Dent) were more accurate and stable. In conclusion, the MSP consisting of N, Dent, and IF shows more accuracy and reliability than the other planes. Further, it is more clinically friendly because of its significant advantage in landmarking.

An attenuation field network for dedicated cone beam breast CT with short scan and offset detector geometry

The feasibility of full-scan, offset-detector geometry cone-beam CT has been demonstrated for several clinical applications. For full-scan acquisition with offset-detector geometry, data redundancy from complementary views can be exploited during image reconstruction. Envisioning an upright breast CT system, we propose to acquire short-scan data in conjunction with offset-detector geometry. To tackle the resulting incomplete data, we have developed a self-supervised attenuation field network (AFN). AFN leverages the inherent redundancy of cone-beam CT data through coordinate-based representation and known imaging physics. A trained AFN can query attenuation coefficients using their respective coordinates or synthesize projection data including the missing projections. The AFN was evaluated using clinical cone-beam breast CT datasets (n = 50). While conventional analytical and iterative reconstruction methods failed to reconstruct the incomplete data, AFN reconstruction was not statistically different from the reference reconstruction obtained using full-scan, full-detector data in terms of image noise, image contrast, and the full width at half maximum of calcifications. This study indicates the feasibility of a simultaneous short-scan and offset-detector geometry for dedicated breast CT imaging. The proposed AFN technique can potentially be expanded to other cone-beam CT applications.

A comparison of estimated age based on pulp volume from cone beam computed tomography (CT) images and panoramic radiography data with chronological age.

This retrospective study was conducted to evaluate different methods for dental age estimation in children and to examine the feasibility of using cone beam computed tomography (CBCT) data for age estimation. A total of 200 radiographic records (both digital panoramic radiographs and CBCTs) were acquired from 100 children aged 9 to 16 years, all taken on the same dates. Radiographic data was acquired from archived records and included both panoramic radiography and CBCT data belonging to the same individual. CBCT was used when panoramic radiographic data was insufficient. The pulp volume and pulp/tooth volume ratio of the left first molar teeth in the mandible were calculated from the CBCT data using MIMICS software. In addition, age was estimated by the Demirjian and Willems methods from data obtained from panoramic radiography images. Statistical analyses and linear regression analysis were performed as necessary. There was a statistically significant difference between the mean difference between the Demirjian method and chronological age, and between the Willems method and chronological age (p < 0.001). Statistically significance was achieved in a linear regression model created from pulp volume (R2 = 0.098) and pulp/tooth volume ratio (R2 = 0.395) data for the estimated dental age analysis (p < 0.001) and a negative correlation was observed with chronological age. When compared estimated dental age from CBCT data with chronological age, the pulp/tooth volume ratio method yielded results closer to chronological age than using only pulp volume data. When considering both panoramic radiographic age estimation methods and age estimation methods using CBCT data, we found that the results obtained with the Willems method, a panoramic radiographic age estimation technique, provided the closest results to the chronological age. More contributions should be made to the literature regarding the feasibility of age estimation using pulp and tooth volume as an alternative method.

Automatic tooth periodontal ligament segmentation of cone beam computed tomography based on instance segmentation network

ObjectiveThe three-dimensional morphological structures of periodontal ligaments (PDLs) are important data for periodontal, orthodontic, prosthodontic, and implant interventions. This study aimed to employ a deep learning (DL) algorithm to segment the PDL automatically in cone-beam computed tomography (CBCT). MethodThis was a retrospective study. We randomly selected 389 patients and 1734 axial CBCT images from the CBCT database, and designed a fully automatic PDL segmentation computer-aided model based on instance segmentation Mask R-CNN network. The labels of the model training were ‘teeth’ and ‘alveolar bone’, and the ‘PDL’ is defined as the region where the ‘teeth’ and ‘alveolar bone’ overlap. The model’s segmentation performance was evaluated using CBCT data from eight patients outside the database. ResultsQualitative evaluation indicates that the PDL segmentation accuracy of incisors, canines, premolars, wisdom teeth, and implants reached 100%. The segmentation accuracy of molars was 96.4%. Quantitative evaluation indicates that the mIoU and mDSC of PDL segmentation were 0.667 ± 0.015 (>0.6) and 0.799 ± 0.015 (>0.7) respectively. ConclusionThis study analysed a unique approach to AI-driven automatic segmentation of PDLs on CBCT imaging, possibly enabling chair-side measurements of PDLs to facilitate periodontists, orthodontists, prosthodontists, and implantologists in more efficient and accurate diagnosis and treatment planning.