Evaluating the relationship between oropharyngeal airway volume and risk of sleep apnea: A cone-beam computed tomography study

To investigate the accuracy and reliability of cone beam computed tomography (CBCT) measurements of buccal alveolar bone height (BBH) and thickness (BBT) using custom acquisition settings. School of Dentistry, Oregon Health & Science University. Twelve embalmed cadavers. Cadaver heads were imaged by CBCT (i-CAT® 17-19, Imaging Sciences International, Hatfield, PA) using a 'long scan' (LS) setting with 619 projection images, 360° revolution, 26.9 s duration, and 0.2 mm voxel size, and using a 'short scan' (SS) setting with 169 projection images, 180° rotation, 4.8 s duration, and 0.3 mm voxel size. BBH and BBT were measured with 65 teeth, indirectly from CBCT images and directly through dissection. Comparisons were assessed using paired t-tests (p≤0.05). Level of agreement was assessed by concordance correlation coefficients, Pearson's correlation coefficients, and Bland-Altman plots. Mean differences in measurements compared to direct measurements were as follows, LS 0.17±0.12 (BBH) and 0.10±0.07 mm (BBT), and SS 0.41±0.32 (BBH) and 0.12±0.11 mm (BBT). No statistical differences were found with any of BBH or BBT measurements. Correlation coefficients and Bland-Altman plots showed agreement was high between direct and indirect measurement methods, although agreement was stronger for measurements of BBH than BBT. Compared to the LS, the similarity in results with the reduced scan times and hence reduced effective radiation dose, favors use of shorter scans, unless other purposes for higher resolution imaging can be defined.

To investigate cone beam computed tomography (CBCT) accuracy in measuring facial bone height and detecting dehiscence and fenestration defects around teeth. Patients who were treatment planned for periodontal flap or dental implant surgeries were enrolled (n = 25). CBCT imaging (Carestream CS 9300) was obtained at 0.09-mm voxels (n = 10 patients, 23 teeth) and at 0.18-mm voxels (n = 15 patients, 33 teeth). Facial bone height measurements, from cusp tip to crest of bone height along the long axis of the tooth, and presence or absence of dehiscence or fenestration defects were recorded from CBCT images in triplicates independently by two examiners. The corresponding clinical measurements were made at the time of surgery. Comparisons of CBCT and clinical measurements were made using paired t tests for teeth: anterior and posterior, maxillary and mandibular, with or without restorations, or root canal therapy. Level of agreement between investigators was assessed by concordance correlation coefficients (CCC), Pearson's correlation coefficient (PCC), and Cohen's Kappa. Comparing mean CBCT and clinical measurements, statistically significant differences were noted for 0.09-mm and 0.18-mm voxel sizes, for anterior and posterior teeth, for maxillary and mandibular teeth, for teeth with or without restorations, and for teeth without root canal therapy (P < .05). Clinical and CBCT measurements were similar for teeth with crowns and with root canal therapy (P > .05). CBCT measurements underestimated mean facial bone height from 0.33 ± 0.78 to 0.88 ± 1.14 mm (mean ± SD) and absolute facial bone height values from 0.56 ± 0.35 to 1.08 ± 0.92 mm. Intraexaminer and interexaminer reliability for measuring facial bone height ranged from poor to substantial (PCC = 0.78 to 0.97 and CCC = 0.63 to 0.96, respectively). Interexaminer reliability for detection of dehiscence and fenestration defects ranged from poor to moderate (Cohen's Kappa = -0.09 to 0.66). CBCT imaging underestimated facial bone height and overestimated the presence of dehiscence and fenestration defects.

To determine the treatment effects of the Xbow appliance on the upper airway dimensions and volume using cone-beam computed tomography (CBCT); to evaluate the cephalometric changes in the skeletal and dental structures of the skeletal Class II patients. The sample consisted of 25 Class II patients (11 male, 14 female) with a mean age of 11.1 ± 1.1 years. CBCT images were obtained at the beginning of the treatment (T0) and after the debonding of the Xbow (T1). Changes in superior, middle, and inferior parts of the oropharynx in the retroglossal region and changes in the oropharyngeal airway volume were statistically significant (P < .05, P < .01). The differences favoring the Xbow for the changes in the direction of Class II correction included SNA, SNB, ANB, maxillary depth angles, and point A-NPg and Co-B distances. Data of the dental parameters showed palatal tipping and extrusion of the maxillary incisors, labial tipping of the mandibular incisors, and mesial movement and extrusion of the mandibular molars. Treatment with the Xbow appliance in Class II patients resulted in favorable increase in the oropharyngeal airway dimensions and volume. Further studies with larger study samples and with control groups are needed.

This study was carried out to assess whether the spatial resolution has an impact on the detection accuracy of proximal caries in flat panel CBCT (cone beam computerized tomography) images and if the detection accuracy can be improved by flat panel CBCT images scanned with high spatial resolution when compared to digital intraoral images. The CBCT test images of 45 non-restored human permanent teeth were respectively scanned with the ProMax 3D and the DCT Pro scanners at different resolutions. Digital images were obtained with a phosphor plate imaging system Digora Optime. Eight observers evaluated all the test images for carious lesion within the 90 proximal surfaces. With the histological examination serving as the reference standard, observer performances were evaluated by receiver operating characteristic (ROC) curves. The areas under the ROC curves were analyzed with two-way analysis of variance. No significant differences were found among the CBCT images and between CBCT and digital images when only proximal enamel caries was detected (p = 0.989). With respect to the detection of proximal dentinal caries, significant difference was found between CBCT and digital images (p < 0.001) but not among CBCT images. The spatial resolution did not have an impact on the detection accuracy of proximal caries in flat panel CBCT images. The flat panel CBCT images scanned with high spatial resolution did not improve the detection accuracy of proximal enamel caries compared to digital intraoral images. CBCT images scanned with high spatial resolutions could not be used for proximal caries detection.

Quantification of external root resorption by low- vs high-resolution cone-beam computed tomography and periapical radiography: A volumetric and linear analysis

Acute Upper Airway Obstruction: Sodium Warfarin-induced Hemorrhage into the Base of the Tongue and Epiglottis

Aim: To compare the implant size which was determined by different observers using panoramic radiography (PAN) and cone beam computed tomography (CBCT) with inserted implant size.Material and Methods: 194 PAN and CBCT images which belong to 194 patients who were planned to undergone single-tooth implant therapy were evaluated. 50 anterior regions, 42 premolar regions and 92 molar regions were assessed. These sites were used for planning of dental implant insertion. Images were analyzed by observers with different education and clinic experience backgrounds: one periodontist (observer 1), one oral and maxillofacial radiologist (observer 2), and one general practitioner (observer 3). Panoramic images and cross-sectional CBCT images of each patient were examined; differences in length and width of the implant-to-be from the two imaging systems were analyzed and compared to inserted implant size.Results: Observer 2 recorded the largest implant width whereas observer 3 recorded narrower implants in PAN. Observer 3 recorded shortest implants than did the other two observers in CBCT and observer 2 recorded narrower implants in CBCT. The CBCT measurements allowed a wider implant in the premolar and molar regions. No significant difference was observed between CBCT and PAN in planning the implant length. The inserted implant size was smaller than the measurements made in CBCT.Conclusion: The results show that; different observers present different values in determining implant length and width. The inserted implant size and the dimensions measured on CBCT and PAN images were different.

Purpose: Optical flow‐based deformable registration algorithm, which assumes that the image intensity does not change during the deformation, is not suitable for cone beam CT (CBCT) and Helical CT (HCT) image registration because CBCT image possesses a intensity inhomogeneity due to Compton scatter effect. The objective of this study is to develop a new deformable registration algorithm for CBCT and HCT image registration. Method and Materials: The proposed deformable registration algorithm for CBCT and HCT image registration is divided into two steps. First, a maximum a posteriori probability (MAP) based adaptive segmentation method is utilized to accurately segment the voxels of CBCT images and HCT images into four tissue types: air, fat, muscle and bone, even in the presence of severe image intensity inhomogeneity due to Compton scatter. The intensities of the segmented images represent the probability of each voxel belonging to different tissue types and are globally uniform. Thus, the image intensity inhomogeneity effect can be eliminated. Second, an optical flow based deformable registration algorithm is applied to the segmented images, instead of original CBCT and HCT image, to determine the deformation between CBCT and HCT images. Thus, the CBCT image can be deformed to match the HCT images. Results: The performance of the proposed deformable registration algorithm was tested using both digital phantoms and clinical CBCT images. Our studies showed that the conventional optical flow‐based method failed to converge to expected solution due to intensity inhomogeneity effect, and its registration results showed a severe mismatch on many detailed structures between CBCT and HCT images. In contrary, the proposed method matched CBCT and HCT image very well. Conclusion: The proposed segmentation‐based deformable registration algorithm is capable of CBCT and HCT image registration.

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First, to compare the upper airway's anatomic and aerodynamic characteristics of the edentulous older adults who experience mild, moderate, and severe obstructive sleep apnea (OSA). Second, to examine the correlation between the severity of OSA and the anatomic and aerodynamic characteristic(s) of the upper airway in these edentulous individuals. NewTom5G cone beam computed tomography scans of 58 edentulous individuals with mild, moderate, and severe OSA were included in this analysis. 1) Computational models of the upper airway were reconstructed based on cone beam computed tomography images and the anatomical and aerodynamic characteristics of the upper airway were examined by an observer blind to OSA severity. 2) Pearson correlation analysis was used to determine the correlation between apnea-hypopnea index and the anatomic and aerodynamic characteristics of the upper airway. Compared with edentulous patients with mild and moderate OSA, those with severe OSA have a more hourglass-shaped upper airway. The severity of OSA, namely, apnea-hypopnea index, was significantly correlated with the length, shape, and minimum cross-sectional area of the upper airway. During inspiration, the mean velocity of the airflow within the upper airway of the edentulous patients with severe OSA was higher than that of patients with mild and moderate OSA. During both inspiration and expiration, apnea-hypopnea index was found to be significantly correlated with maximum velocity (P = .05) and airway resistance (P = .024, 0.038). The edentulous patients with severe OSA have a more hourglass-shaped upper airway. The findings also suggest that, during inspiration, the airflow travels faster in edentulous patients with severe OSA than in those with mild or moderate OSA. Registry: ClinicalTrials.gov; Name: The Effect of Nocturnal Wear of Dentures on Sleep and Oral Health Related Quality of Life; URL: https://clinicaltrials.gov/ct2/show/NCT01868295; Identifier: NCT01868295. Chen H, Elham E, Li Y, etal. Comparison of anatomic and aerodynamic characteristics of the upper airway among edentulous mild, moderate, and severe obstructive sleep apnea in older adults. J Clin Sleep Med. 2022;18(3):759-768.

Three-dimensional C-arm Cone-beam CT: Applications in the Interventional Suite

Does Changing Image Guidance Processes Impact Patient Setup Practice?

Condyle position in Class II Division 1 malocclusion patients: Correlation between MPI records and CBCT images

Fossa navicularis (FN) is defined as bony depression that is not always present and is located anterior to the foramen magnum and pharyngeal tubercle on the inferior aspect of the basilar part of the occipital bone. It has been reported that FN can create an infection spread path from the pharynx to the intracranial structures. Therefore, the diagnosis of this variation is important. Although cone beam computed tomography (CBCT) diagnostic accuracy has mostly been verified in detection and quantification particularly on human skulls, there is no study comparing morphometric measurements between direct measurement on the skull and CBCT measurement. The main object of this study is to evaluate the presence of FN on dry bones and CBCT images of the same dry skull and to examine the morphometric and morphological features of this formation. Thirty-two random craniums that were made available for this study that did not have any fractures or deformities of the cranial base were examined. The sagittal diameter, transverse diameter, and depth of the FN was measured both directly on dry skulls and radiologically on CBCT images of dry skull. In addition, the shape of FN (SFN) was determined. FN was detected in 10 (31.25%) of 32 craniums examined with both modalities. It was determined that sagittal diameter of the FN, transverse diameter of the FN, depth of the FN, and the shape of FN did not show a statistically significant difference between the 2 measurements. Unlike the literature, FN was investigated on dry bones both directly and in CBCT images in this study. In contrast to previously thought the FN may be smaller according to this findings, and this small variation can be detected with CBCT images. According to this findings, it can be said that morphometric evaluations on CBCT are accurate and reliable, and CBCT is a safe method for clinical diagnosis and treatment.

To test the null hypothesis that there are no significant differences in pharyngeal airway volumes among adult patients with different vertical skeletal patterns and a clinically normal sagittal skeletal pattern using cone-beam computed tomography (CBCT). The study sample consisted of 100 adult patients (45 men and 55 women; mean age = 24.0 ± 5.3 years) with a normal sagittal skeletal pattern divided into three groups according to the vertical skeletal patterns: high angle (32 patients: 15 women and 17 men), low angle (34 patients: 14 women and 20 men), and normal angle (34 patients: 16 women and 18 men) groups. Nasopharyngeal, oropharyngeal, and total airway volumes of patients in all vertical groups were calculated. Group differences were analyzed using one-way analysis of variance and post hoc Tukey tests. Nasopharyngeal airway volume in the high-angle group (mean = 6067.9 ± 1693.9 mm(3)) was significantly lower than that of the low- and normal-angle groups (P < .01). Oropharyngeal airway volume was highest in the low-angle group (mean = 15,957.6 ± 6817.2 mm(3)) and significantly decreased in the control (mean = 11,826.1 ± 4831.9 mm(3); P = .008) and high angle (mean = 10,869.1 ± 4084.1 mm(3); P = .001) groups. Total airway volume was highest in the low-angle group (mean = 24,261.6 ± 8470.1 mm(3)) and lowest in the high-angle group (mean = 16,937.0 ± 5027.4 mm(3); P < .001). The null hypothesis was rejected. Significant differences were found in pharyngeal airway volumes among different skeletal vertical patterns.