Differences in the panoramic appearance of cleft alveolus patients with or without a cleft palate.

Purpose: The purpose of this study was to clarify the panoramic image differences of cleft alveolus patients with or without a cleft palate, with emphases on the visibility of the line formed by the junction between the nasal septum and nasal floor (the upper line) and the appearances of the maxillary lateral incisor. Materials and Methods: Panoramic radiographs of 238 patients with cleft alveolus were analyzed for the visibility of the upper line, including clear, obscure or invisible, and the appearances of the maxillary lateral incisor, regarding congenital absence, incomplete growth, delayed eruption and medial inclination. Differences in the distribution ratio of these visibility and appearances were verified between the patients with and without a cleft palate using the chi-square test. Results: There was a significant difference in the visibility distribution of the upper line between the patients with and without a cleft palate (p<0.05). In most of the patients with a cleft palate, the upper line was not observed. In the unilateral cleft alveolus patients, the medial inclination of the maxillary lateral incisor was more frequently observed in patients with a cleft palate than in patients without a cleft palate. Conclusion: Two differences were identified in panoramic appearances. The first was the disappearance (invisible appearance) of the upper line in patients with a cleft palate, and the second was a change in the medial inclination on the affected side maxillary lateral incisor in unilateral cleft alveolus patients with a cleft palate.

Unusual imaging appearance of cemental tear in the maxillary first molar on cone-beam computed tomography: A case report.

A cemental tear (CeT) is a definitive clinical entity and its radiographic appearance is well known in single-rooted teeth. However, the imaging features of CeT in multi-rooted teeth have not been clarified. We report a case of CeT which arose in the maxillary first molar and exhibited an unusual appearance in cone-beam computed tomography images. The torn structure was verified as cementum by micro-computed tomography and histological analysis. The hypercementosis, most likely induced by occlusal force, might have been torn from the root by a stronger occlusal force caused by the mandibular implant. An unusual bridging structure was created between the two buccal roots. These features may occur in multi-rooted teeth with long-standing deep pockets and abscesses that are resistant to treatment.

Alterations of posterior pharyngeal wall movement during swallowing in postoperative tongue cancer patients: assessment with a videofluoroscopic swallowing study.

This study aimed to determine the association between the progressive contraction of the posterior pharyngeal wall and dysphagia in postoperative patients with tongue cancer. A videofluoroscopic swallowing study (VFSS) was performed in 34 patients after tongue cancer surgery. Images were analyzed using a two-dimensional video measurement software. Cases in which the processes on the posterior pharyngeal wall moved downward from the 2nd to 4th vertebral regions were defined as "normal type", other cases were defined as "abnormal type". Twenty-four patients showed normal movement of the posterior pharyngeal wall, whereas 10 patients showed the abnormal type. The results showed that there was a significant difference in dysphagia scores between the postoperative swallowing type and swallowing dysfunction score. This implies that dysphagia is related to the movement of the posterior pharyngeal wall after tongue cancer surgery. Furthermore, the extent of resection and stage were significantly different between the normal and abnormal groups in the posterior pharyngeal wall movement. There was also a significant difference between the two groups in terms of the following: whether the tongue base was included in the excision range (p < 0.01), whether neck dissection was performed (p < 0.01), or whether reconstruction was not performed (p < 0.01). VFSS results showed that posterior pharyngeal wall movement was altered after surgery in patients with tongue cancer who had severe dysphagia.

Multiple assessment of molars with hypercementosis lost due to periodontitis using X-ray micro-computed tomography, electron microprobe analysis, and histological sections.

This article aimed to achieve a better understanding of cementum hyperplasia in the maxillary second molars lost due to periodontitis. Six maxillary second molars with hypercementosis were measured for the mineral concentration using micro-computed tomography and calcium element distributions using electron microprobe analysis. Calcium was distributed throughout the cementum, although the mineral concentration differed based on the cementum depth. The hyperplastic cementum was of the extrinsic fiber-rich cellular mixed stratified type. These results have implications for future studies aiming to diagnose hypercementosis. Further studies are needed to investigate the composition of the cementum matrix.

Preliminary Study on the Diagnostic Performance of a Deep Learning System for Submandibular Gland Inflammation Using Ultrasonography Images.

This study was performed to evaluate the diagnostic performance of deep learning systems using ultrasonography (USG) images of the submandibular glands (SMGs) in three different conditions: obstructive sialoadenitis, Sjögren's syndrome (SjS), and normal glands. Fifty USG images with a confirmed diagnosis of obstructive sialoadenitis, 50 USG images with a confirmed diagnosis of SjS, and 50 USG images with no SMG abnormalities were included in the study. The training group comprised 40 obstructive sialoadenitis images, 40 SjS images, and 40 control images, and the test group comprised 10 obstructive sialoadenitis images, 10 SjS images, and 10 control images for deep learning analysis. The performance of the deep learning system was calculated and compared between two experienced radiologists. The sensitivity of the deep learning system in the obstructive sialoadenitis group, SjS group, and control group was 55.0%, 83.0%, and 73.0%, respectively, and the total accuracy was 70.3%. The sensitivity of the two radiologists was 64.0%, 72.0%, and 86.0%, respectively, and the total accuracy was 74.0%. This study revealed that the deep learning system was more sensitive than experienced radiologists in diagnosing SjS in USG images of two case groups and a group of healthy subjects in inflammation of SMGs.

Clinical assessment of cemento-osseous dysplasia based on three-dimensional diagnostic imaging: A case report.

Cemento-osseous dysplasia (COD) is a lesion in which periapical bone is replaced by fibrous tissue, including osseous or cementum-like tissue. In the initial stage of COD, radiolucencies are noted at the root apex on periapical radiography, which can be confused with apical periodontitis. Understanding of correct pathological condition and careful assessment of COD is critical to avoid unnecessary endodontic interventions in healthy teeth. This report describes the ability and usefulness of cone-beam computed tomography (CBCT) and multi-slice computed tomography (MSCT) to detect COD. The findings in this case suggest that MSCT is more appropriate than CBCT, especially for patients with early- to middle-stage COD. However, the radiation dose is higher in MSCT than in CBCT; the application of MSCT should be limited to assessment of whether treatment or surgical management is necessary.

Computed tomographic features of synovial chondromatosis of the temporomandibular joint with a few small calcified loose bodies.

OBJECTIVES: The present study aimed to clarify the characteristic computed tomography (CT) features that indicate synovial chondromatosis (SC) with a few small calcified bodies or without calcification on panoramic images, and to discuss their differences from the features of temporomandibular disorder (TMD). METHODS: Panoramic and CT images from 11 patients with histologically verified SC of the temporomandibular joint were investigated. Based on the panoramic images, the patients were classified into a distinct group (5 patients) with typical features of calcified loose bodies and an indistinct group (6 patients) without such bodies. On the CT images, findings for high-density structures suggesting calcified loose bodies, joint space widening, and bony changes in the articular eminence and glenoid fossa (eminence/fossa) and condyle were analyzed. RESULTS: All 5 distinct group patients showed high-density structures on CT images, while 2 of 6 indistinct group patients showed no high-density structures even on soft-tissue window CT images. A significant difference was found for the joint space distance between the affected and unaffected sides. A low-density area relative to the surrounding muscles, suggesting joint space widening, was observed on the affected side in 2 indistinct group patients. All 11 patients regardless of distinct or indistinct classification showed bony changes in the eminence/fossa with predominant findings of extended sclerosis and erosion. CONCLUSION: Eminence/fossa osseous changes including extended sclerosis and erosion may be effective CT features for differentiating SC from TMD even when calcified loose bodies cannot be identified.

A rare case of hyperostosis frontalis interna in an 86-year-old Japanese female cadaver.

Hyperostosis frontalis interna (HFI) is a condition characterized by abnormal bone outgrowth on the inner surface of the frontal bone. Most HFI cases occur in post-menopausal elderly women. The pathology of HFI development is uncertain. The estimated incidence of HFI ranges from 5 to 12% in Western countries, but few cases have been reported in the Japanese population. Here, we report a case of HFI in an 86-year-old Japanese female cadaver. Macroscopically, the internal surface of the frontal bone exhibited bilateral nodular protrusion with sparing of the midline, while the external surface was normal. According to the morphological classification of HFI proposed by Hershkovitz et al. this case belongs to type D, the most severe type. Using computed tomography (CT), we defined five layers, designated as I-V from the inner to the outer layer, in the nodular region of HFI; however, the normal frontal bone is composed of three layers. Histological results demonstrated that layers I, III, and V consisted of the cortical bone, and layers II and IV consisted of the trabecular bone. We also observed increases in the numbers of lamellar bone and blood vessels on the dural side of layer I, indicating increased vascularization and active osteogenesis. These results indicate that layer II represents a new diploe within the inner table, which split into layers I and III, suggesting that diploization within the inner table by activated remodeling may be involved in the development of hyperostosis in this case.

Automatic measurement of mandibular cortical bone width on cone-beam computed tomography images.

OBJECTIVE: The computed tomography cortical index (CTCI), computed tomography mandibular index (CTMI), and computed tomography index (inferior) [CTI(I)] are indexes obtained from cone-beam computed tomography images for the assessment of the mandibular cortex quality for implant planning or osteoporosis. However, cross-sectional image reconstruction for the measurements is labor-intensive. This study aimed to develop and evaluate a method to automatically reconstruct cross-sectional images and measure the cortex width in all areas inferior to the mental foramen (MF). METHODS: Seventy-one women (mean age: 52.4 years; range: 20-78 years) were enrolled. They were divided into four age and CTCI groups, including females younger (FY) and females older (FO) than 50 years (C1: normal, C2: mild/moderate erosion, and C3: severe porosity). Automatic and manual measurements of CTMI and CTI(I) were compared, and the inter- and intraobserver agreements were assessed using the intraclass correlation coefficient (ICC). The relationships between CTMI or CTI(I) and CTCI were also assessed. RESULTS: The mean processing times for reconstruction and measurements were 31.9 s and 1.22 s, respectively. ICCs for the comparison of automatic and manual measurements were 0.932 and 0.993 in the C1 and C2/C3 groups, respectively. Significant differences in CTMI and CTI(I) were observed between the FY or the FO-C1 and FO-C3 groups (p < 0.05). CONCLUSION: The automatic and manual measurements showed a strong agreement. The new method could drastically reduce routine clinical workload. Additionally, our method enables the measurement of the cortex width in all the mandibular bones inferior to the MF.

Reliability of diagnostic imaging for degenerative diseases with osseous changes in the temporomandibular joint with special emphasis on subchondral cyst.

OBJECTIVES: The present study aimed to clarify the reliabilities of four characteristic appearances, subchondral cyst, erosion, generalized sclerosis, and osteophyte, for evaluation of degenerative diseases with osseous changes in the temporomandibular joint (TMJ) using panoramic TMJ projection imaging and computed tomography (CT), and to investigate the imaging features of these modalities for subchondral cyst with reference to its magnetic resonance imaging (MRI) features. METHODS: The reliabilities (κ values) of panoramic TMJ projection and CT images were determined by three radiologists for each characteristic appearance of TMJ osseous changes in 146 condyles. The features of cyst-like areas on CT images with agreement among the three radiologists were investigated for size, location, and continuity with the joint space together with MRI signal intensity and surrounding edema-like lesions. RESULTS: Panoramic TMJ projection images showed moderate and substantial agreements for erosion and osteophyte evaluations, respectively; while CT images showed substantial agreements for subchondral cyst, erosion, and osteophyte evaluations. Cyst-like areas on CT images were predominantly located in the central parts and 69 of 86 (80.2%) areas showed no communication with the joint space. Cyst-like areas with diameters exceeding 2 mm showed high or moderate MRI signal intensities. Edema-like lesions were observed in 10 of 28 (29.4%) condyles. CONCLUSIONS: The reliabilities of panoramic TMJ projection and CT images were clarified for each characteristic appearance. The results support the bone contusion theory for the formation of subchondral cysts in the TMJ. A possible improvement in reliability is suggested relative to MRI findings.

Clinical guidelines for dental cone-beam computed tomography.

Dental cone-beam computed tomography (CBCT) received regulatory approval in Japan in 2000 and has been widely used since being approved for coverage by the National Health Insurance system in 2012. This imaging technique allows dental practitioners to observe and diagnose lesions in the dental hard tissue in three dimensions (3D). When performing routine radiography, the examination must be justified, and optimal protection should be provided according to the ALARA (as low as reasonably achievable) principles laid down by the International Commission on Radiological Protection. Dental CBCT should be performed in such a way that the radiation exposure is minimized and the benefits to the patient are maximized. There is a growing demand for widespread access to cutting-edge health care through Japan's universal health insurance system. However, at the same time, people want our limited human, material, and financial resources to be used efficiently while providing safe health care at the least possible cost to society. Japan's aging population is expected to reach a peak in 2025, when most of the baby boomer generation will be aged 75 years or older. Comprehensive health care networks are needed to overcome these challenges. Against this background, we hope that this text will contribute to the nation's oral health by encouraging efficient use of dental CBCT.

Quantification of voxel values in micro computed tomography using multiple porosity hydroxyapatite blocks.

Microfocus X-ray computed tomography (micro-CT) has been applied as a method for the nondestructive and detailed assessment of trabecular bone patterns and tooth structure. Voxel values obtained from micro-CT are not absolute values. Therefore, voxel values were assessed using hydroxyapatite (HA) blocks with a different vesicle rate to quantify voxel values of micro-CT images in the present investigation.HA blocks with 4 levels of porosity and a block with a soft tissue-equivalent density were used, and the voxel values of each block were measured. Correlations between voxel values of micro-CT and HA densities were analyzed. Also, black and white binary images were produced, and the ratios of white pixels to pixels in regions of interest (ROIs) were calculated. The relationship between voxel values of micro-CT and HA densities could be regressed using a linear equation, and the correlation coefficient was high. Also, there were no significant differences in the regression equations between the first and second times. Voxel values of micro-CT might be convertible to HA densities using a regression equation.

Longitudinal observation of maxillary sinus bony bridges and septa in childhood.

The rate of septum presence in the maxillary sinus has been reported to be over 30%. It was considered that a bony bridge might change to a maxillary sinus septum with growth in a previous study using dry child skulls. In the present investigation, maxillary sinus bony bridges and septa were longitudinally observed using computed tomography (CT). Multislice CT was performed in three patients. A bony bridge was defined as a bony structure between the maxillary sinus wall and dental germ. Also, a septum was defined as a pointed bony structure in the inferior wall of the maxillary sinus. The height and angle of the bony bridge/septum and the distance between the base of the bony bridge/septum and bony palate were measured. In three patients, the bony bridge in the maxillary sinus floor was observed in the second molar on the first CT, and the maxillary sinus septum was observed on the second CT at the same site. In conclusion, it was longitudinally observed that a bony bridge changed to a maxillary sinus septum with growth, such as root formation and tooth eruption.

Optimizing the reconstruction filter in cone-beam CT to improve periodontal ligament space visualization: An in vitro study.

PURPOSE: Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. MATERIALS AND METHODS: Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. RESULTS: Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. CONCLUSION: Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.

Computed tomographic assessment of early changes of the mandible in bisphosphonate-treated patients.

OBJECTIVES: To compare the computed tomography (CT) features of mandibular cancellous and cortical bones between patients with bisphosphonate (BP) administration and those without and to assess the early changes of the mandible in BP-treated patients. STUDY DESIGN: Twenty-four BP-treated patients suffering from medication-related osteonecrosis of the jaw (MRONJ) were enrolled in this study. For comparison, 20 patients suffering from osteomyelitis and 20 patients without pathology in the jaw were also enrolled, all of whom did not receive BP treatment. The CT values of the cancellous and cortical bone and the cortical bone widths were measured. RESULTS: In the MRONJ and osteomyelitis groups, there were significant differences in the CT values of cancellous and cortical bones between the affected and unaffected areas. In patients with stage 0 MRONJ, a significant difference was noted in the cancellous bone CT values between these areas. The cancellous bone CT values at the affected and unaffected areas in the BP-treated group were significantly higher than in the control groups. In patients with stage 0 MRONJ, the cancellous bone CT values at the affected area were also significantly higher than in the healthy patients. The cortical bone widths in the unaffected areas in the BP-treated patients were significantly larger than in healthy patients. CONCLUSIONS: The cancellous bone CT values were higher in the BP-treated group, including in patients with stage 0 MRONJ, and CT may provide useful quantitative information.

Protuberance or fossa on the lateral surface of the mandible in primates.

In order to clarify the morphological characteristics and function of the protuberance and/or fossa on the lateral surface of the mandible, we examined 778 mandibles of 9 genera, 19 species of non-human primates. Both protuberance and fossa were found in Macaca, Chlorocebus, and Cercocebus at frequencies ranging from 0% to 60%. The protuberance was composed of compact bone and was similar to the mandibular torus in humans. A well-developed protuberance extended from the fourth premolar to third molar region, and was situated at the central part of the mandibular body, or continued on the oblique line. Sometimes the protuberance localized on the mandibular base. A deep and large fossa was found in all individuals of Papio, Theropithecus, and Mandrillus, and the bone width was thin in the center of the fossa. The fossa extended from the third premolar to the second molar region, and the deepest area was the first molar region. In Macaca, Chlorocebus, and Cercocebus, the curvature of the external table of the mandible created a fossa. In Colobus, and Hylobates, the external surface of the mandible looked concave because of the thickened mandibular base. These concavo-convex structures have some biological functions and represent an adaptive change for mastication.

Observation of maxillary incisive canal using dry skulls between Hellman's dental age IA and IIIC.

The maxillary incisive canals were observed in childhood from infancy to school-aged children to clarify their development. Cone-beam computed tomography was performed to investigate 44 dry child skulls. Two-dimensional images of various planes in the maxillary incisive canal were reconstructed on a computer using 3-dimensional visualization and measurement software. Then, antero-posterior angulation, and antero-posterior and lateral axes of the maxillary incisive canal were measured at the inferior and middle levels. The mean difference of angulation between the inferior and middle levels was 2.3 degrees in IIC, and 11.1 degrees in IIIC. The mean ratio of the lateral axis to antero-posterior axis at the middle level was 2.54 in IIC, and 1.93 in IIIC. In conclusion, it was antero-posteriorly straight from IA to IIC, and, after IIIA, it curved at the middle level. The cross-sectional shape in IIC was depressed with a larger lateral axis.

Relationship between findings of mandibular cortical bone in inferior border and bone mineral densities of lumbar vertebrae in postmenopausal women.

It is important to assess the general bone condition in dental implant treatment. The relationships between the bone mineral densities (BMDs) of lumbar vertebrae and mandibular cortical bone condition in the inferior border using multi-slice computed tomography (CT) were assessed in postmenopausal women. If a strong correlation between them is obtained, the mandibular cortical bone condition may be useful to evaluate the general bone condition. Twenty-two postmenopausal women were enrolled in this investigation. The maximum CT value and width of the mandibular cortical bone (MCW-MSCT) were measured, and the mandibular cortical bone index (MCI-MSCT) was classified using multi-slice CT. BMDs of lumbar vertebrae were measured using dual energy X-ray absorptiometry (DXA), and then the percentage of the young adult mean (YAM) was analyzed. The correlations were investigated between the mandibular cortical bone condition and values of lumbar vertebrae. Weak correlations were observed between MCW-MSCT and the percentage of YAM. Also, significant differences in the percentage of YAM were noted between types of MCI-MSCT. The mandibular cortical bone index (MCI-MSCT) in the inferior border using multi-slice CT may be applicable to evaluate the influence of the general bone condition.