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We prepared Mo and Cr co-loaded ZSM-5 (Mo/Cr/ZSM-5) by a sequential impregnation method and applied it to methane dehydroaromatization (MDA) reaction.

Zr-doped SAPO-34 has enhanced Lewis acidity, leading to high catalytic activity for LDPE cracking.

Mg and Zn co-doped mesoporous ZSM-5 was prepared via impregnation of Mg and a Zn ion exchange using a commercial ZSM-5, which achieved a high yield of BTX and the improvement of catalyst lifetime on EDA reaction.

This study evaluates the effect of loading various mono and divalent metals in Beta zeolite on low-density polyethylene (LDPE) cracking. We revealed that Tl and Ba ions enhanced Lewis acidity, leading to higher catalytic activity on LDPE cracking.

This study is one of the few to develop a strategy that inhibits coke deposition by loading Cr on zeolite defects. We revealed that Cr6+ species, which interacted with hydroxyl groups in the zeolite framework inhibited coke deposition.

The objective was to introduce a new technique for visualizing the three-dimensional (3D) movements of velopharyngeal-related muscles using high-speed cine-magnetic resonance imaging (MRI) based on T2-weighted sequences. The evaluation of phonation- and water swallowing-related events was performed in 11 healthy subjects. Specifically, whether cine-MRI could precisely visualize normal velopharyngeal function during these two events was examined. The 3D movements of the soft palate, superior pharyngeal constrictor muscles, and levator veli palatini muscles were visualized in all 11 subjects. A noteworthy finding was that the magnetic resonance signals of the superior constrictor pharyngeal muscles and the levator veli palatini muscles were significantly higher during phonation and during water swallowing than at rest. This initial study suggests that the 3D movements of velopharyngeal-related muscles can be successfully and precisely visualized without side effects. The magnetic resonance signal changes seen in the superior pharyngeal constrictor and levator veli palatini muscles using the technique described here should be useful to develop better methods of evaluation of velopharyngeal function.

Objective The aim of this study was to evaluate the characteristics of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values of ranulas. In addition, to elucidate DWI findings and ADC values of other representative masses in and around the floor of the mouth. Study Design DWI findings and ADC values in 35 patients with ranulas and 33 patients with other masses were retrospectively reviewed with a central focus on cystic masses or lesions that may have cyst-like components in and around the floor of the mouth based on the diagnosis of each respective disease. Results Ranulas were all well-defined, homogeneous masses with high signal intensity on DWI. The mean ± standard deviation ADC value of the 35 ranulas was 2.59 ± 0.31 × 10−3 mm2/s. There was a significant difference in ADC values between simple and plunging ranulas. On DWI, most other masses were heterogeneous, and most ADC values, except those for thyroglossal duct cysts, hemangiomas, and pleomorphic adenomas, were significantly lower than those for ranulas. Conclusions The characteristic DWI and ADC findings of ranulas can be determined accurately, and these data can be significantly useful in the differential diagnosis of many kinds of diseases in and around the oral floor.

Purpose According to the literature, ultrasonic surgery reduces the incidence of neurosensory disturbance (NSD) of the inferior alveolar nerve (IFAN) after bilateral sagittal split osteotomy (BSSO). The purpose of this study was to evaluate the effects of ultrasonic surgery and the anatomic position of the IFAN canal on NSD after BSSO. Patients and Methods This retrospective cohort study included skeletal mandibular prognathism cases operated on with an ultrasonic bone scalpel or a reciprocating saw. The primary predictor variable was osteotomy technique (ultrasonic or conventional surgery). The primary outcome variable was NSD. Other variables included age, gender, operator, degree of setback, surgical duration, blood loss, and IFAN position. Comparisons of 2 variables were performed by use of the Student t test or Fisher exact test. A regression model was used to examine the relationship between the presence or absence of NSD and other variables. The level of significance was set at P Results The ultrasonic group was composed of 35 patients, whereas the conventional group was composed of 32. Three months after surgery, NSD was observed on 16 of 70 sides (22.9%) in the ultrasonic group and 28 of 64 sides (43.8%) in the conventional group; this difference was significant. Furthermore, recovery from NSD at 3 months after BSSO was significantly more common in the ultrasonic group than in the conventional group. In the ultrasonic group, even when the distance from the buccal aspect of the IFAN canal to the outer buccal cortical margin was shorter, NSD of the IFAN was less frequent. Conclusions Ultrasonic surgery may be an effective technique to reduce the incidence of NSD after BSSO, and it contributed to recovery from NSD. The use of an ultrasonic device for BSSO is recommended when the distance from the buccal aspect of the IFAN canal to the outer buccal cortical margin is shorter on computed tomography.

Numerous studies, including our own, have revealed that positron emission tomography–computed tomography (PET/CT) using fluorine-18-labeled fluoro-2-deoxy-d-glucose (18F-FDG) is effective for the diagnosis of oral cancers. Large amounts of new information about primary tumors and metastatic lymph nodes have been acquired, and the use of 18F-FDG PET/CT has been shown to improve diagnostic precision in determining both the pathological characteristics of primary oral cancers and the presence of metastatic lymph nodes. However, substantial variations in 18F-FDG uptake in the oral and maxillofacial regions have been identified, and the differential diagnosis of some oral cancers and metastatic lymph nodes remains difficult for radiologists. Therefore, based on the previous research, the aim of the present study was to review the basic and important points regarding the diagnosis of primary oral cancers and metastatic lymph nodes using 18F-FDG PET/CT.

Background: 18 F-fluoro-2-deoxy-D-glucose ( 18 F-FDG) accumulations are commonly seen in the neck-related muscles of the surgical and non-surgical sides after surgery with neck dissection (ND) for oral cancers, which leads to radiologists having difficulty in diagnosing the lesions. To examine the alterations in 18 F-FDG accumulation in neck-related muscles of patients after ND for oral cancer. Material and Methods: 18 F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) in neck-related muscles were retrospectively analyzed after surgical dissection of cervical lymph nodes in oral cancers. Results: According to the extent of ND of cervical lymph nodes, the rate of patients with 18 F-FDG-PET-positive areas increased in the trapezius, sternocleidomastoid, and posterior neck muscles of the surgical and/or non-surgical sides. In addition, SUVmax of 18 F-FDG-PET-positive areas in the trapezius and sternocleidomastoid muscles were increased according to the extent of the ND. Conclusions: In evaluating 18 F-FDG accumulations after ND for oral cancers, we should pay attention to the 18 F-FDG distributions in neck-related muscles including the non-surgical side as false-positive findings

Objectives The purpose of this study was to identify the spatial relationship and/or association between odontomas and the gubernaculum tract or the dental sac and the characteristic findings for radiographic diagnosis of odontomas. Study Design The visualizations of the odontomas and the gubernaculum tract were retrospectively analyzed using cone beam computed tomography or multidetector computed tomography. Results Most of odontomas were within the gubernaculum tract or dental sac of unerupted permanent teeth on computed tomography. In some odontomas, the gubernaculum tract existed as a well-defined low density tract extending from the top of odontomas on computed tomography. Conclusions A close spatial relationship and/or association between odontomas and the gubernaculum tract or dental sac on computed tomography may be used as one of the criteria for radiographic diagnosis of odontomas. Development of odontomas may be associated with the gubernaculum tract or dental sac of unerupted permanent teeth.

OBJECTIVE To develop a model of osteonecrosis using oral bisphosphonate in ovariectomy-induced osteoporotic rats. MATERIALS AND METHODS Thirty-six rats were subjected to ovariectomy or sham surgery. After 8 weeks, rats received oral alendronate (1.0 mg kg(-1) ) or saline once weekly for 4 weeks; then, serum C-telopeptide cross-linked collagen type I levels were measured to evaluate bone metabolism. Twelve rats from each group were injected with either lipopolysaccharide or saline into the bone marrow of the mandibles and femurs, and the areas of osteonecrosis were evaluated by histomorphometry. RESULTS Serum C-telopeptide cross-linked collagen type I levels were significantly increased in the ovariectomy group (105.1 ± 2.1 ng ml(-1) ) compared with the sham group (78.9 ± 12.5 ng ml(-1) ); they were significantly reduced following oral alendronate administration in the ovariectomy group (91.0 ± 4.4 ng ml(-1) ). Following alendronate and lipopolysaccharide administration, extensive osteonecrosis was observed in the mandibles and femurs of ovariectomy (0.45 ± 0.08 mm(2) , 1.69 ± 0.72 mm(2) , respectively) and sham (1.12 ± 0.45 mm(2) , 1.84 ± 0.66 mm(2) , respectively) groups. Significantly wider osteonecrosis occurred in the mandibles of sham-operated rats than ovariectomy rats following alendronate or lipopolysaccharide treatment. CONCLUSIONS We successfully developed a model of osteonecrosis in ovariectomised rats following oral bisphosphonate administration.

A Stafne bone defect is a static bone depression in the mandible that is commonly observed in cortical bone near the mandibular angle. We herein present a rare case in which static bone depressions attached to the three major salivary glands were observed on panoramic radiography and computed tomography (CT). The three static bone depressions in the mandible were visualized on a panoramic radiograph and CT as oval radiolucent masses in a 68-year-old man. The CT numbers in the bone depressions ranged from 10 to 50 HU, and they were close to those of the respective salivary glands. Based on the CT numbers, the areas in the bone depressions were determined to be a normal parotid gland, sublingual gland, and submandibular gland. The patient underwent a follow-up examination and did not request further consultation.

Objectives The aim of this study was to determine the usefulness of evaluating the function of swallowing before and after surgery in patients with tongue cancer by using T2-weighted sequences of high-speed continuous magnetic resonance imaging (HSCMRI). Study Design The imaging findings and related parameters on HSCMRI along with those on routine MRI examinations before and after surgery were examined in 19 patients with tongue cancer. In addition, changes in various parameters during 1 year after surgery were evaluated in 10 patients. Results In most patients examined, the direction of flow to the esophagus could be seen on HSCMRI before and after surgery. Significant correlations were observed among 4 parameters and in the responses to a dysphagia questionnaire. Conclusions The results of the present study suggest that the dynamics of swallowing can be directly visualized on HSCMRI by using 4 parameters that permit the evaluation of changes before and after surgery, and this enables objective evaluation of patients' swallowing complaints.

Objective The purpose of this retrospective study was to evaluate the predictability and accuracy of maxillary repositioning during bimaxillary surgery using a three-dimensional positioning technique. Study Design Twenty-six adult patients who underwent bimaxillary surgery requiring high superior maxillary impactions were divided into 2 groups. In group A, a three-dimensional positioning technique during maxillary repositioning was used along with an intermediate occlusal splint. In group B, only an intermediate occlusal splint with internal reference points was used. Both groups had measurements from predictive tracings compared to postoperative cephalograms to assess the accuracy of horizontal and vertical movements of the maxilla. Results Group A showed excellent correlation between the planned and actual maxillary positions in vertical and horizontal dimensions. In group B, the maxilla tended to move anteriorly than planned. Conclusions Use of the three-dimensional positioning technique offered a predictive and accurate method for maxillary repositioning.

Objectives To elucidate whether fluorine-18-labeled ( 18 F) fluoro-2-deoxy- d -glucose (FDG) accumulation can reflect the extent of periodontal inflammation, periapical inflammation, or dental caries. Study Design 18 F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) were retrospectively compared with the size of the bone resorption areas caused by periodontal inflammation, periapical inflammation, or dental caries on panoramic radiographs, CT, and magnetic resonance imaging (MRI) in 44 subjects. Results A significant correlation was found between the size of the bone resorption area caused by periodontal ( r = 0.595, P r = 0.560, P 18 F-FDG accumulation. A significant correlation was found between the periodontal ( r = 0.622, P r = 0.394, P 18 F-FDG accumulation. The SUVmax of 18 F-FDG around most teeth with caries was under 1.5. Conclusions 18 F-FDG accumulation reflects the extent of dental inflammation, not dental caries.

Objective Posterior repositioning of the maxilla using a novel modification in combined Le Fort I and horseshoe osteotomy in bimaxillary surgeries is described and assessed for accuracy. Materials and methods In this prospective study, posterior repositioning of maxilla was performed in a total of 10 patients where the planned posterior setback was at least 3 mm or greater. In all patients, the maxilla was first osteotomized with Le Fort I and horseshoe osteotomy in addition to a new technique to trim maxillary tuberosity and posterior palatal walls, and followed by bilateral sagittal split ramus osteotomy in the mandible with or without additional genioplasty. Lateral cephalograms were obtained preoperatively and 1 week postoperatively. The changes in upper incisor (U1) and upper molar mesial cusp tip (UMT) were examined. Results The discrepancy between the planned and actual posterior movement was 0.35 and 0.28 mm at U1 and UMT, respectively. There were no severe complications such as intraoperative haemorrhage, avascular necrosis of the maxilla (partial/total), devitalization of teeth, and oroantral or oronasal fistulas in any of the cases. Conclusions These results suggest that when greater posterior repositioning of the maxilla is indicated, this newly introduced novel modification in horseshoe osteotomy combined with Le Fort I osteotomy is an effective technique for safety and accuracy.

Objectives The aim of this study was to evaluate the 3-dimensional images of thinner main peripheral vessels in oral and maxillofacial regions made without contrast medium by using a new technique, fresh blood imaging (FBI). A second objective was to discern arteries from veins by using the combination of FBI with the subtraction technique. Study design Images from FBI were compared with those from 3-dimensional phase-contrast magnetic resonance angiography (MRA) of blood vessels in 20 healthy subjects. All images were scored for visualization and image quality of the main blood vessels. In addition, appropriate flow-spoiled gradient pulses were applied to differentiate arteries from veins in the peripheral vasculature using a combination of FBI sequences and subtraction between systole- and diastole-triggered images. Results The scores of MRA using FBI for the visualization of thin blood vessels were significantly better than those using phase contrast, whereas scores for the visualization of main blood vessels were equal. Additionally, we succeeded in our initial attempt to differentiate arteries from veins with a reasonable acquisition time. Conclusions Our initial experience shows that FBI could be a useful method to identify 3-dimensional vasculature and to differentiate arteries from veins among thinner peripheral vessels in the oral and maxillofacial regions without using contrast medium.

Objective The objective of this study was to evaluate the clinical significance of ultrasonography (US) for screening for thyroid gland diseases when surveying the cervical lymph nodes to detect metastasis in subjects with oral squamous cell carcinoma (SCC). Methods The detection rates and characteristics of abnormal thyroid findings detected by US in 301 subjects with oral SCC were analyzed. Subjects with abnormal findings were referred to thyroid specialists and the diagnoses and treatments from these specialists were noted. The ratio of subjects who consulted a thyroid specialist after indications of thyroid gland abnormalities to analyze subject compliance was also examined. Follow-up examinations were regularly conducted to assess any changes in the thyroid gland. Results Of the 301 subjects with oral SCC, 91 had abnormal thyroid gland findings on US. As subject age increased, the rate of detection of abnormal thyroid gland findings on US significantly increased. The rate of detection of abnormal findings in women by US was significantly higher than that in men, but the male-to-female ratio was lower compared with that in previous reports. It was demonstrated that oral SCC in the floor of the mouth was associated with the highest prevalence of abnormal findings in the thyroid gland (40%), followed by oral SCC of the maxillary gingiva (39%). Of the 91 subjects with abnormal findings, 10 showed enlargement in the size of the lesion on follow-up examination with US. Eleven subjects with no abnormal findings on initial examination showed abnormal findings on follow-up examination. Conclusion The results suggest that subjects with oral SCC have a relatively high rate of abnormal findings in the thyroid gland that can be detected by US. Scans that include the thyroid gland should be performed when surveying cervical lymph nodes for metastasis during US examination. Particular attention should be paid to thyroid gland–related diseases in older men who have oral cancer and to thyroid gland abnormalities if patients had oral SCC in the floor of the mouth or of the maxillary gingiva. It is recommended that follow-up US examinations be regularly performed in cases of oral SCC.

Infectious arthritis of the temporomandibular joint (TMJ) is rare, and previous reports have identified malocclusion resulting from condylar deformity and displacement of the condyle as one of the clinical characteristics of the disease. Here we report the case of a 33-year-old man with chronic infectious arthritis of the TMJ without malocclusion associated with osteomyelitis of the right mandible. Based on radiological findings of more prominent inflammation at the TMJ than in other regions and on the observed efficacy of antibiotic administration, we made a diagnosis of suppurative arthritis of the TMJ. Based on our empirical experience, including the present case, we speculate that refusal to cooperate with medical care may be a factor in the development of infectious arthritis of the TMJ.

Objectives:To elucidate the changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose (18F-FDG) accumulation in the tongue muscles of patients following four kinds of surgical operations for tongue cancers.Methods:The changes in the distributions of 18F-FDG accumulations in the tongue muscles on positron emission tomography (PET)-CT, in association with imaging findings on CT and MRI, were retrospectively analyzed before and after four kinds of surgical operations for 50 patients with tongue cancers.Results:18F-FDG-PET-positive areas appeared at the back of the intrinsic muscles of the tongue after invasive surgery for tongue cancers despite the absence of abnormal findings on CT and MRI. A correlation between the standardized uptake value maximum of 18F-FDG in the intrinsic muscles and the degree of invasiveness of the surgical procedures for tongue cancers (r = 0.539, p

Purpose To elucidate the appearance and imaging characteristics of the gubernacular tract (GT) during the growth stage of children. Furthermore, this study evaluated the significance of the appearance of the GT. Study Design The visualizations of the GT were retrospectively analyzed by using panoramic radiographs and computed tomography (CT) in children. Results In patients with normal eruption who had unerupted permanent teeth, except maxillary central supernumerary teeth, the GT was clearly visualized as a well-defined low-density tract on CT but not on panoramic radiographs. In patients with obstructive eruption, including impaction, the GT was deformed and not visible on CT. Conclusions This paper describes the frequency of detection and appearance of the GT in unerupted teeth. Preliminary data suggest that any alteration to the GT may be used to predict abnormal eruption of permanent teeth.

Objective To introduce a new high-speed, continuous, T2-weighted magnetic resonance imaging (MRI) technique for the evaluation of swallowing by visualizing the flow of saline. Study Design In 20 healthy participants, high-speed (10 frames per second), continuous MRI of the pharynx and larynx was performed during administration of 5 mL of saline. The extent to which fluid flow and swallowing (including flow to the esophagus or trachea) could be visualized was determined for all 20 participants. Results Solution flow was visualized, and swallowing events, including the direction of flow to the esophagus, could be visualized with high-speed, continuous MRI for all 20 participants. Conclusions This initial study suggests that the visualization of saline flow using our method may facilitate functional evaluation of swallowing without side effects.

The pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ) is highly controversial. We have previously reported the development of osteonecrosis by periodontal pathogenic stimulation in the jaw and femur of rats treated with bisphosphonate. Since the major toxicity factor of Gram-negative bacteria is lipopolysaccharide (LPS), the present study aimed to evaluate the relationship between osteonecrosis and LPS in a rat model of BRON-like lesions. Seventeen male rats were injected subcutaneously with zoledronic acid weekly for 4 weeks and divided into three groups: LPS (LPS administered into the bone marrow of the mandible and femur) and LPS plus polymyxin B (PMB) and saline groups (given neutralized LPS with PMB or saline, respectively, using the same protocol). At 4 weeks after the procedure, harvested specimens were analyzed using histomorphology (n=5 from each group) and histochemistry (n=1 each from LPS and LPS plus PMB groups). There was a significantly wider area of osteonecrosis in the LPS group as compared to the saline and LPS plus PMB groups in both the mandible (P=0.030 and P=0.009, respectively) and femur (P=0.002 and P=0.020, respectively). Our results indicate that LPS stimulation is deeply involved in the development and promotion of BRON.

Background Recent studies suggest that tonsilloliths are clinically related to halitosis and tonsillar abscess. Based on our empirical knowledge, tonsilloliths are relatively commonly encountered in daily clinical practice. It has been reported that the detection rate of tonsilloliths was under 24% in previous reports, although experience suggests otherwise. The purpose of the study was to evaluate the prevalence and characteristics of tonsilloliths using computed tomography (CT). In addition, the possible causes of low detection rates on panoramic radiographs were evaluated based on comparisons between CT images and panoramic radiographs in order to elucidate the limitations of visualizing the area around the palatine tonsils on panoramic radiographs. Methods 482 pairs of CT images and panoramic radiographs were retrospectively assessed with respect to the presence and characteristics of tonsilloliths. In addition, the causes in cases of disagreement between the two modalities were analyzed. Results The detection rate of tonsilloliths was 46.1% using CT scans, unlike previous reports. The characteristics of tonsillolith were dot-like figures with about 300-500 Hounsfield units within the palatine tonsil under the soft palate. The most common length of tonsilloliths was about 3 or 4 mm. As the subjects aged, the detection rate increased gradually. A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p Conclusion The present results suggest that tonsilloliths are relatively more common than previously suggested. However, panoramic radiographs detect only a small percentage of palatine tonsilloliths. The low detection rates on panoramic radiographs might be related to the degree of calcification, size, and number of tonsilloliths.

Objective To elucidate the characteristics of visualizing thin main peripheral vessels in oral and maxillofacial regions of 3-dimensional magnetic resonance angiography (MRA) using a balanced steady-state free-precession (SSFP) sequence with a time-spatial labeling inversion pulse (time-SLIP) and using fresh blood imaging (FBI). Study Design The conspicuity of blood vessels and the characteristics on MRA using SSFP with a time-SLIP was compared with those on MRA using FBI in 20 healthy participants. Results The conspicuity of the main peripheral arteries was significantly higher on MRA using SSFP with a time-SLIP than on MRA using FBI. MRA scans using SSFP were obtained in all participants, and scans using FBI were obtained in 16 of 20 participants. An electrocardiogram was unnecessary when using SSFP but was necessary when using FBI. Conclusions MRA obtained using SSFP with a time-SLIP is a useful technique to visualize thin main peripheral arteries in the oral and maxillofacial regions without contrast medium.

Clinically, bisphosphonate-related osteonecrosis (BRON) only occurs in the jaw (BRONJ). We aimed to determine differences between the jaw and other bones, as well as the relationship between periodontal pathogens and BRON. Twelve male Wistar rats were divided into two groups: group Z (n=6) were subcutaneously injected with zoledronic acid weekly for 4 weeks; group C (n=6) were injected with saline. One week after the final injection, rats in both groups were divided into three subgroups: Aa subgroup was injected with freeze-dried Aggregatibacter actinomycetemcomitans into bone marrow of the mandibles and femurs, while CFA and saline subgroups were injected with complete Freund's adjuvant (CFA) or saline using the same protocol. Four weeks after those injections, the rats were euthanized. Areas of osteonecrosis were measured histologically. Statistically, rats in group Z showed significantly wider osteonecrosis areas in both mandibles and femurs with each type of local injection than rats in group C. In group Z, mandibles and femurs stimulated with A. actinomycetemcomitans or CFA had significantly wider osteonecrosis areas than those stimulated with saline. We have developed a rat model with BRONJ-like lesions. Our results showed BRON to develop not only in the jaw but also in other types of bone following an inflammatory stimulus.

To elucidate whether fluorine-18-labeled ((18)F) fluoro-2-deoxy-d-glucose (FDG) accumulation can reflect the extent of periodontal inflammation, periapical inflammation, or dental caries.(18)F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) were retrospectively compared with the size of the bone resorption areas caused by periodontal inflammation, periapical inflammation, or dental caries on panoramic radiographs, CT, and magnetic resonance imaging (MRI) in 44 subjects.A significant correlation was found between the size of the bone resorption area caused by periodontal (r = 0.595, P.01) or periapical (r = 0.560, P.01) inflammation and the highest standardized uptake value (SUVmax) of (18)F-FDG accumulation. A significant correlation was found between the periodontal (r = 0.622, P.01) or periapical (r = 0.394, P.01) inflammatory findings on MRI and the SUVmax of (18)F-FDG accumulation. The SUVmax of (18)F-FDG around most teeth with caries was under 1.5.(18)F-FDG accumulation reflects the extent of dental inflammation, not dental caries.

The purpose of this study is to elucidate the criteria and limitations for selecting a sagittal split ramus osteotomy (SSRO) alone for patients with skeletal mandibular prognathism and open bite.The relationship between the mandibular relapse after 1 year and the extent of vertical movement following SSRO alone was investigated for patients with skeletal mandibular prognathism and open bite and the criteria were determined.The limitation in SSRO alone was found to be 3-mm vertical movement at the gonion. There was a significant difference in the mandibular relapse between the patients with3-mm change and3-mm change.For patients with skeletal mandibular prognathism and open bite, if the vertical movement at the gonion is3 mm, SSRO alone could be an effective treatment. However, if the movement is3 mm, SSRO alone should be avoided and bimaxillary osteotomies may be a preferable treatment.

The present paper provides general dentists with an introduction to the clinical applications and significance of magnetic resonance angiography (MRA) in the oral and maxillofacial regions. Specifically, the method and characteristics of MRA are first explained using the relevant MR sequences. Next, clinical applications to the oral and maxillofacial regions, such as identification of hemangiomas and surrounding vessels by MRA, are discussed. Moreover, the clinical significance of MRA for other regions is presented to elucidate future clinical applications of MRA in the oral and maxillofacial regions.

Computed tomography (CT) scanning is very useful in identifying and evaluating the location, size, and suspected pathological diagnosis of lesions such as cysts, tumors, and infections. At the same time, it aids in the elucidation of bone and surrounding soft tissue invasion of lesions with high resolution.1, 2 In the maxilla and mandible, teeth are included and the CT capacity there can distinguished a foreign body of only 30 μm. Precise size and location are needed in the evaluation of lesions in the maxilla and mandible based on a high resolution in addition to the suspected pathological diagnosis based on CT findings. Therefore, multi-detector CT (MDCT) scanning is commonly applied for various kinds of lesions in the maxilla and mandible because of its precision and diagnostic accuracy. Multidetector CT scanning provides rapid acquisition of numerous thin axial images and more accurate reconstruction images. Multi-detector CT scanning provides accurate information about the height, width, and three-dimensional (3D) evaluation of the maxilla and mandible, as well as detailed information about the location of normal anatomical structures, such as the mandibular canal, mental foramen, mandibular foramen, incisive foramen, and maxillary sinus. In addition, the relationship between lesions and anatomical landmarks, including cortical margins and roots of teeth, can be established. These images are also excellent because MDCT eliminates streak artifacts from dental restorations that degrade direct coronal CT scans. With MDCT, axial images are used to reformat the cross-sectional images, projecting the artifact along the crowns of the teeth rather than over the bone that is the region of interest.3 At the same time, CT readings of lesions in the maxilla and mandible measured by MDCT can reflect the nature and inclusion within lesions, from which

Various kinds of diseases may be found in the oral and maxillofacial regions and various modalities may be applied for their diagnosis, including intra-oral radiography, panoramic radiography, ultrasonography, computed tomography, magnetic resonance imaging, and nuclear medicine methods such as positron emission tomography. Of these modalities, ultrasound imaging is easy to use for the detection of noninvasive and soft tissue-related diseases. Doppler ultrasound images taken in the B-mode can provide vascular information associated with the morphology of soft tissues. Thus, ultrasound imaging plays an important role in confirming the diagnosis of many kinds of diseases in such oral and maxillofacial regions as the tongue, lymph nodes, salivary glands, and masticatory muscles. In the present article, we introduce three new applications of ultrasonography: guided fine-needle aspiration, measurement of tongue cancer thickness, and diagnosis of metastasis to cervical lymph nodes.

Purpose This report describes a case that required emergency cricothyroidotomy for an upper airway obstruction owing to laryngeal edema after asynchronous bilateral neck dissections. Patient and Methods A 57-year-old man was diagnosed with multicentric squamous cell carcinoma of the tongue (T1 and 2N0M0), and partial glossectomy with primary closure was performed. Three months after surgery, secondary metastases in the right cervical lymph nodes were detected, and a right radical neck dissection was performed. Contrast-enhanced computed tomographic (CT) scan taken 2 weeks after the right neck dissection visualized a possible third metastasis in the left cervical lymph node. Four weeks after the right radical neck dissection, left supraomohyoid neck dissection was carried out. In this surgery, the left internal jugular vein (IJV) was preserved. Nine hours after surgery, severe swelling of the face and pharynx was recognized, resulting in a stoppage of respiration and then an emergency cricothyroidotomy. Results The patient's life was saved without any encephalopathy or airway trouble. Contrast-enhanced CT scan taken the next day confirmed the preserved left IJV patency. Conclusion Oral and maxillofacial surgeons should be aware of the possibility of life-threatening laryngeal edema associated with bilateral neck dissections even if the unilateral IJV is preserved and should know the procedure for emergency cricothyroidotomy.

To elucidate the points that require attention when interpreting fluorine-18-labelled fluoro-2-deoxy-d-glucose ((18)F-FDG)/positron emission tomography (PET) images by demonstration of (18)F-FDG accumulation in various areas of the oral cavity other than primary lesions in patients with oral cancers.(18)F-FDG accumulations with a maximal standardized uptake value of over 2.5 in various areas of the oral cavity other than primary lesions were identified in 82 patients with oral cancers.(18)F-FDG/PET-positive areas, excluding primary tumours, included the front intrinsic muscles of the tongue (89.0%), upper and lower marginal parts of the orbicularis oris muscle (64.6%), sublingual glands, palatine tonsil, pharyngeal tonsil, and lingual tonsil. In addition, some areas in the jaws also showed accumulation.In patients with oral cancers, areas of (18)F-FDG accumulation in the oral cavity should be precisely identified and appropriately diagnosed, because accumulations can be seen in areas other than the primary tumour.