Search

Objectives The shapes of gubernaculum tracts (GTs) in molars as accessional teeth remain unidentified. To elucidate imaging peculiarities of GTs in molars with aging on multidetector‐row computed tomography (MDCT). Material and methods This retrospective study was conducted using CT images, including maxillary and mandibular molars, with no abnormal findings from 239 patients. Shapes of alveolar bone, GTs, and dental sacs of the maxillary and mandibular molars were analyzed multi‐sectionally. Correlations between 2‐ and 3‐dimensional imaging figures of GTs in molars and chronological age or stage of molar formation were analyzed. Results Some forms of GTs in maxillary and mandibular third molars were observed. In the early stage, GTs were visualized as bone defect lines on the dentition and grooves on the mesial alveolar crest continuous with the dental sac to mesial tooth bud. GTs of the third molar formed a J‐shape in maxillary teeth and Y‐shape in mandibular teeth in the middle stage, as alveolar bone around the GT developed. In the mature stage, the course of the GT changed to straight and perpendicular. Some GT forms were also identified in first and second molars. Significant correlations were found between GT alterations and chronological age or stage of molar formation. Moreover, tracts continuing from the distal side of mandibular third molars were detected. Conclusions This paper describes the peculiarities and process of progression for GTs in molars, and the existence of tracts continuing from the distal side of mandibular third molars, unlikely dentition with deciduous predecessors. These preliminary data should prove beneficial for studies focusing on GTs in molars.

The aim of this study was to evaluate whether a balanced steady-state free-precession (SSFP) sequence with a time–spatial labeling inversion pulse (time–SLIP) without contrast medium could elucidate branches of the lingual and facial arteries on the lingual aspect of the mandible as a potential technique for preventing severe complications in dental implantation surgery. In this study, magnetic resonance angiography (MRA) using SSFP with a time–SLIP was evaluated in 40 subjects. The outline and course of branches of the lingual and facial arteries near the mandible were assessed clinically in the same subjects against contrast-enhanced computed tomography (CT) images as the gold standard. The submental, sublingual, and deep lingual arteries could be visualized via MRA in 16, 20, and 16 of the 40 subjects, respectively. The major axes of the respective arteries were approximately 24, 24, and 16 mm. The outline and course of all visualized arteries coincided with those on CT. MRA using SSFP with a time–SLIP appears to have potential as a non-contrast technique for visualizing branches of the lingual and facial arteries on the lingual aspect of the mandible. Information regarding the outline and course of these arteries as obtained using this MRA technique could assist in preventing severe complications in dental implantation surgery.

The purpose of this study was to elucidate the imaging characteristics of the gubernaculum tracts in successional teeth related to fused deciduous teeth on computed tomography. The imaging findings of 15 gubernaculum tracts in successional teeth related to fused deciduous teeth were retrospectively analyzed using cone-beam computed tomography or multidetector computed tomography. In cases without a congenitally defected successor, the two gubernaculum tracts of two successional teeth related to fused deciduous teeth were fused into one. Gubernaculum tracts (GTs) in mesial successors were vertical, but in distal successors they were inclined to mesial. The major abnormalities of the successional teeth related to fused deciduous teeth were delayed eruption and delayed formation. No inclined mesial successors were found, whereas most of the distal successors were inclined to mesial along with the inclined GT. The gubernaculum tracts of successors with a congenital defect of the other successors were vertical, and such successors had no abnormalities. The present study showed the imaging characteristics of gubernaculum tracts in successional teeth related to fused deciduous teeth. The abnormal eruption of successional teeth related to fused deciduous teeth may be associated with the characteristics of their gubernaculum tracts.

The eruption pathway from the dental follicle to the gingiva for permanent teeth is known as the gubernaculum tract (GT), a physiologic structure thought to play a role in tooth eruption. Cone beam computed tomography and multi-detector computed tomography have recently been used to visualize the GT, with the results indicating that this structure might be related to the normal eruption of teeth. By contrast, curved and/or constricted GTs may lead to abnormal tooth eruption. In addition, complex odontomas have been reported from within the GT or dental sac of unerupted permanent teeth. If an odontoma occurs within the GT, the tooth will not erupt normally. Moreover, the imaging characteristics of the GT from the top of the odontogenic mass to the alveolar crest are extremely useful for making a differential pathological diagnosis and for differentiating between odontogenic and non-odontogenic masses. Therefore, radiological studies on the GT have been attracting increasing attention. Given this background, the present review aims to clarify the imaging characteristics and review recent studies on the GT considering the importance of the research.

This study was done to determine whether the sublingual gland ducts could be visualized and/or their function assessed by MR sialography and dynamic MR sialography and to elucidate the clinical significance of the visualization and/or evaluation of the function of sublingual gland ducts by clinical application of these techniques. In 20 adult volunteers, 19 elderly volunteers, and 7 patients with sublingual gland disease, morphological and functional evaluations were done by MR sialography and dynamic MR sialography. Next, four parameters, including the time-dependent changes (change ratio) in the maximum area of the detectable sublingual gland ducts in dynamic MR sialographic images and data were analyzed. Sublingual gland ducts could be accurately visualized in 16 adult volunteers, 12 elderly volunteers, and 5 patients. No significant differences in the four parameters in detectable duct areas of sublingual glands were found among the three groups. In one patient with a ranula, the lesion could be correctly diagnosed as a ranula by MR sialography because the mass was clearly derived from sublingual gland ducts. This is the first report of successful visualization of sublingual gland ducts. In addition, the present study suggests that MR sialography can be more useful in the diagnosis of patients with lesions of sublingual gland ducts.

To assess the mandibular cortical width (MCW) and morphology of the mandibular inferior cortex (MIC) on panoramic views from a large sample of males and females in various age groups by using an automated morphometric grading system for assisting osteoporosis screening. Furthermore, possible predictors and concrete cut-off values to identify the risk for osteoporosis were evaluated.MCW, MIC, tooth loss (TL), and alveolar bone loss (ABL) were retrospectively evaluated in 700 panoramic images from dental patients in Hong Kong using commercially available software. To estimate possible predictors for identifying the risk of osteoporosis, age, TL, and ABL were evaluated with the receiver operating characteristic (ROC) curves for each gender separately.The age groups 60s (sixties), 70s and 80s showed statistically significant gender differences. For example, a smaller MCW and more MIC Class 3 were found in females. Furthermore, females exhibited a statistically significant increase in TL in the age groups 50 years and above. In males, age, TL or ABL did not correlate with MCW, whereas in females it statistically significantly did. Meanwhile, the correlation between ABL and MCW and MIC was weak for both genders. Concrete cut-off values to identify patients at risk of osteoporosis were 60.15 years and 3.5 missing teeth in females, and 72.55 years in males.Age and tooth loss were related to MCW and MIC in the population investigated. An age of ≥60 as well as more than 3.5 teeth lost seem to be indicators for a risk of osteoporosis in Chinese females based on panoramic views using artificial-intelligence-based software.

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.

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.

Objective The aim of this study was to evaluate whether a new cine-magnetic resonance imaging (CMRI) technique might be useful for evaluating swallowing function in patients with different types of oral cancers by assessing 12 CMRI-related parameters. Study Design In total, 111 patients with oral cancers were evaluated. We examined whether visualization of fluid flow and determination of flow direction to the trachea or the esophagus were possible with CMRI. We evaluated the correlations between CMRI-related parameters and self-reported dysphagia scores as the status of dysphagia, T classification groups as tumor staging for preoperative patients, alterations in CMRI-related parameters between pre- and postoperative patients, and the degree of invasiveness of oral cancer surgery. Results We could judge the flow direction to the esophagus on CMRI in all 111 patients. Six CMRI-related parameters showed significant correlations with dysphagia status. Increases in CMRI-related parameters were significantly related to deterioration of swallowing status, as shown by a decrease in self-reported dysphagia scores, advances in the T classification, and degree of invasiveness of oral cancer surgery. Conclusions The results of the present study suggest that CMRI can be used to directly visualize swallowing dynamics and objectively evaluate the swallowing complaints of patients with oral cancer.

Objectives To elucidate the characteristics of the gubernaculum tracts (GTs) in maxillary anterior teeth with normal or delayed eruption and in mesiodens by using multidetector computed tomography and cone beam computed tomography. Study Design The characteristics of GTs in maxillary anterior teeth of 205 patients with impacted mesiodens were retrospectively analyzed by using multidetector computed tomography and cone beam computed tomography. The GTs of teeth with normal or delayed eruption and the GTs of mesiodens were examined. Results The detection ratio of GTs in impacted mesiodens and anterior teeth with delayed eruption was significantly lower than in teeth with normal eruption. A significant difference in the angulation was found between normal and delayed eruptions. Almost all detectable GTs in the inverted mesiodens were derived from the incisive canal, while the remaining were from the alveolar crest. The connecting area of major GTs to tooth in inverted mesiodens was the cervical or root area, but in all other anterior teeth, it was the crown area. Conclusions GTs of inverted mesiodens may exhibit characteristics that are different from those of normal GTs when the teeth and/or the palate are developing.

Objective: The aim of this study was to examine whether a decreased occurrence rate of adverse drug reactions (ADRs) to contrast media in contrast-enhanced CT and MRI was attributable to appropriate criteria for patients with some diseases. A secondary aim was to elucidate safety profiles for contrast media and factors influencing the occurrence of ADRs. Methods: Clinical data of patients who underwent contrast-enhanced CT (5576 cases) or MRI (3357 cases) were retrospectively analyzed to evaluate rates of ADRs to contrast media, symptoms of ADRs, treatments for ADRs, and differences in medical history, blood test results, and other factors between patients with and without ADRs in a dental hospital. Results: The rate of ADRs to contrast media was 0.54% for CT and 0.09% for MRI. The most frequent ADRs in contrast-enhanced CT or MRI were nausea and vomiting as physiologic reactions. Two serious reactions were seen for CT, but none for MRI. Significant differences between patients with and without ADRs were seen in liver function according to blood tests for CT, and in digestive disorders elicited from medical interviews for MRI. Conclusion: The lower occurrence rate of ADRs to contrast media in dental hospitals could be due to the adoption of appropriate criteria for patients with some diseases undergoing enhanced CT or MRI. Complete suppression of ADRs to contrast media for CT or MRI is unrealistic, so attention is warranted for patients with decreased liver function when performing enhanced CT, and for patients with digestive disorders when performing enhanced MRI.

The aim of this study was to determine whether the evaluation of neurovascular compression (NVC) using new criteria on magnetic resonance (MR) cisternography improves the prediction of the curative effects of carbamazepine (CBZ) in trigeminal neuralgia (TN). In this study, a new analysis of NVC using MR cisternography was performed retrospectively for 280 patients with clinical signs and symptoms suggesting TN. The new analysis examined whether the site of the NVC was less than 3mm from the edge of the exit point and within the first third of the root entry zone on MR cisternography. Prediction of the curative effects of CBZ using the new evaluation of distance to the NVC improved on the predictive ability of the previous method of calculating the NVC volume (Mantel-Haenszel coefficient, P 5mm3. The evaluation of NVC on MR cisternography using this new approach appears to be more useful than the previous method for predicting the initial treatment response in patients with TN.

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.

Diffuse chronic sclerosingosteomyelitis (DCSO) is a refractory disease, becausethe etiology and pathogenesis remain poorly understood and to determine the border betweenunhealthy boneandhealthybone is difficult. However, progressive inflammation, clinical symptoms and a high recurrence rate of DCSO were the reasons for surgical treatment. We report a case of a 66-year old woman with DCSO of the right side of mandible who was treated with hemimandibulectomy and simultaneous reconstruction by vascularized free fibula flap. After preoperative administration of minocycline for 1 month, the bone fluorescence was successfully monitored by using a Visually Enhanced Lesion Scope (VELscope®). Intraoperatively, we could determine the resection boundaries. We investigated the clinical and histopathological findings. The fluorescence findings were well correlated with histopathological findings. Using a VELscope®was handy and useful to determine the border between DCSO lesion andhealthybone.The free fibula flap under the minocycline-derived bone fluorescence by using a VELscope®offered a good quality of mandibular bone and the successful management of an advanced and refractory DCSO. Key words:Fluorescence-guided bone resection, fibular free flap, osteomyelitis of the mandible, diffuse chronicosteomyelitis, VELscope®.

In recent years, dysphagia is problem among elderly people. Therefore, it is necessary to accurately evaluate swallowing function in order to prevent swallowing disorder beforehand or to detect it early, and it is considered that evaluation of swallowing function using MRI is useful, and the demand for development of CAD system using MRI is increasing. In order to accurately analyze the swallowing motion, automatic extraction of the region of interest by the image analysis method is necessary. In this paper, as a pretreatment of a method for automatic extraction of esophageal region on dental MR image, we develop automatic extraction method of spinal candidate region. We first extract the posterior region of the spine and then extract the intervertebral disc region. Then we perform the detection of the anterior region of the spine and finally we extract the region between the anterior region of the spine and the posterior region of the spine as a spinal region. The proposed method was applied to 5 cases of dental MR images, and the results of TP 91.2 [%] and FP 8.8 [%] are obtained.

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.

The mechanism of late implant failure is unclear. This study examined the association between sclerosing cancellous bone images and the risk of late implant failures using multi-detector row computed tomography (CT) imaging data. We performed a case–control study. The study group consisted of consecutive patients with implant failures treated at Kyushu Dental University between 2001 and 2016. CT data for late failure of 36 implants in 16 patients were available. The study cohort consisted of 16 patients with 36 late failed implants and 28 patients with 113 successful implants. The mean survival rate was 6.9 months for early implant failure, 76.6 months for late failure with marginal bone resorption, inflammation symptoms, and so-called peri-implantitis, and 95.0 months for late failure caused by implant fracture. The mean HU value for cases in the control group was 507 compared with 1231 for cases with late failure implants. Logistic regression was used for analysis. There were signs of high radiodensity of peri-implant cancellous bone when comparing adjusted radiodensity per 100 HU using CT data (OR 2.35; 95% CI 1.73–3.20; p

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.

Objectives: To elucidate the predisposing factors and clinical characteristics related to the occurrence of stitch abscess after surgery in patients with oral squamous cell carcinoma (SCC). Patients and Methods: The subjects were 232 patients who underwent excision and/or reconstruction and/or neck dissection for oral SCC using silk sutures for high ligation of the blood vessels. Detection rates and characteristics of patients with stitch abscess were retrospectively evaluated by comparing patients with and without stitch abscesses after surgery diagnosed by ultrasonography and findings of various modalities in 232 patients. Several echogenic dots with subtle acoustic shadows in a hypoechoic mass were identified as the characteristic findings of stitch abscess on US. The patient groups with and without stitch abscess were compared with respect to various factors to identify those that predispose to the occurrence of stitch abscess. The factors analyzed included patients’ sex and age, chemotherapy treatment, radiotherapy treatment, the presence of a history of allergy, and blood test results. Results: A significant correlation was found between the occurrence of stitch abscess and age, liver function abnormalities on blood tests, and the presence of a history of allergy. Multiple stitch abscesses clearly tended to occur more often than single ones in patients with stitch abscess. Conclusions: The occurrence of stitch abscesses was related to age, liver dysfunction, and/or the presence of allergies. When diagnosing stitch abscess, the occurrence of multiple stitch abscesses is important. Key words:Stitch abscess, oral cancer, predisposition, characteristics, squamous cell carcinoma.

This review article provides doctors and dentists with an introduction to the clinical applications and sig- nificance of magnetic resonance cisternography (MRC) for the evaluation of neurovascular compression of the trigeminal nerve in patients with trigeminal neu- ralgia (TN). Specifically, the method and characteris- tics of MRC are first explained using the relevant MR sequences. Next, clinical applications for the diagnosis of TN are discussed. Finally, the significance and util- ity of MRC for effective treatment of patients with TN, such as carbamazepine administration and/or local anesthetic blocks, are presented.

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.

Our aim was to find out whether the quality of bone around the inferior alveolar nerve is correlated with neurosensory disturbance to the nerve after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. Computed tomograms (CT) were taken of 35 patients with mandibular prognathism and 35 without. To assess the density of bone around the inferior alveolar nerve, the width of the buccal cortical bone in the mandibular second molar regions was measured on CT. The Hounsfield units (HU) in the same regions were also measured. The number of HU in the mandible around the second molar regions was significantly higher (p

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 aim of this study was to evaluate the effect of altering changing head and body positions on the 2- and 3-dimensional (3D) configuration of the oropharynx with jaw protrusion. Study design Twelve healthy individuals (8 male, 4 female) with no history of sleep disturbances were invited to participate. For each subject, an acrylic splint was made with the mandible in protruded position. Subjects were imaged using magnetic resonance imaging in 4 different jaw, head, and body positions: 1) supine without protrusion; 2) supine with jaw protrusion; 3) supine with head rotation and jaw protrusion; and 4) laterally recumbent position with jaw protrusion. The 2- and 3D images of the upper airway in different positions were reconstructed by using a free DICOM reconstruction software. The dimension changes (anteroposterior and lateral dimensions, cross-sectional area, and volume) of the oropharynx (divided into retropalatal region and retroglossal region) were calculated and analyzed. Statistical analyses were performed using the Bartlett test and 1-way analysis of variance with α = .05. Results Compared with nonprotruded position, dimensions of the oropharynx for both retropalatal region and retroglossal regions were found to be greater than with jaw protrusion. Head and body positions had little effect on configuration of the oropharynx with jaw protrusion in either 2- or 3D. The only change noted was a greater anteroposterior dimension of retropalatal region with head rotation and lateral supine position compared with the supine position. Conclusions Head and body positions have little effect on 2- and 3D airway dimensions on supine patients with jaw protrusion.

To elucidate the relationship between the anatomic position of the inferior alveolar nerve (IAN) at the mandibular second molar and the occurrence of neurosensory disturbances of the IAN after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. Also, the present study evaluated the difference in anatomic position of the IAN between patients with and without mandibular prognathism.Computed tomography images were taken of 28 patients with mandibular prognathism and 30 without prognathism. On these scans, the IANs from the mandibular second molar region to the mandibular foramen in the mandibular ramus were identified. The present study was designed as a cross-sectional study. The distance from the buccal aspect of the IAN canal to the outer buccal cortical margin of the mandible in the mandibular second molar regions was measured on the computed tomography images. Also, the linear distance between the superior aspect of the IAN canal and the alveolar crest in these regions was calculated. In addition, we investigated the presence or absence of contact between the IAN canal and the inner buccal cortical margin of the mandible from the mandibular second molar to the mandibular foramen in the mandibular ramus. Next, we examined whether neurosensory disturbances occurring after SSRO were related to the position of the IAN at the mandibular second molar.A significant difference was found in the occurrence of neurosensory disturbances of the IAN after SSRO between men and women (χ(2) test, P.05). For the distance from the buccal aspect of the IAN canal to the outer buccal cortical margin of the mandible in the mandibular second molar region, a significant difference was found between groups with and without neurosensory disturbances (Student's t test, P.01). The shorter the distance from the buccal aspect of the IAN canal to the outer buccal cortical margin, the more frequent the occurrence of neurosensory disturbances of the IAN.The present results have demonstrated that gender and the anatomic position of the IAN canal at the mandibular second molar are significantly related to the occurrence of neurosensory disturbances of the IAN after SSRO. Therefore, surgeons should clearly inform patients of the increased possibility of neurosensory disturbances after SSRO when the patients are female and are found to have a shorter distance from the buccal aspect of the IAN canal to the outer buccal cortical margin.

Purpose Exact estimation of tumor thickness and the status of the resection margin in tongue carcinoma are important prognostic factors for local recurrence, subclinical nodal metastasis, and survival. This study aims to evaluate the accuracy of intraoral ultrasonography-guided measurement of tumor thickness and define an adequate intraoperative resection margin in squamous cell carcinomas of the tongue. Materials and Methods In this prospective study, 13 patients with presurgical, biopsy-proven, clinical T1N0 or T2N0 tongue squamous cell carcinomas who underwent a partial glossectomy were examined preoperatively with ultrasonography to assess tumor thickness under general anesthesia. Nine cases underwent resection by a conventional method, whereas we introduced elastic needles with a metal core to mark a deep surgical margin of 10 mm from the deepest tumor invasion front under ultrasonographic monitoring as a new technique in the remaining 4 cases. Each resected specimen was immediately immersed in gelatin solution while maintaining its original shape and orientation and was placed under refrigeration to solidify. Ultrasonographic observations of the gelatin-embedded specimens were performed from the superior surface of the gelatin block. Results Very fine ultrasonographic images of the resected specimen could be easily obtained without any special skills, and surgical clearance could be verified intraoperatively. The ultrasonographic tumor thickness measurements corresponded well with those of histologic sections, with a consistency ratio of 91.4% to 98.2% (Pearson correlation coefficient = 0.981, P Conclusion Intraoperative ultrasonography is a reliable method to objectively evaluate tumor thickness and surgical margin clearance.

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.

Various modalities are available for the diagnosis of diseases affecting the oral and maxillofacial regions. The currently used imaging modalities include intra-oral radiographs, panoramic radiographs, magnetic resonance imaging (MRI), computed tomography (CT) including cone-beam (CB) CT, ultrasonography (US), and nuclear medicine including positron emission tomography (PET). In the present review, we describe the application and significance of each modality in the diagnostic process of oral and maxillofacial diseases. Keywords: Panoramic radiograph, cone beam CT, MRI, PET-CT, US, imaging, oral and maxillofacial. INTRODUCTION The discovery of the X-ray by WC Roentgen in 1895 be-gan the history of diagnostic imaging of the human body, including that of oral and maxillofacial regions. Since then, a number of diagnostic imaging modalities have been devel-oped. Different modalities are applied for the diagnosis of diseases in oral and maxillofacial regions, and many reports have suggested the usefulness of intra-oral radiographs, panoramic radiographs, magnetic resonance imaging (MRI), computed tomography (CT), ultrasonography (US), and nu-clear medicine including positron emission tomography (PET). In the present review, we introduce the applications of each modality and explain the significance of its image in the diagnosis of oral and maxillofacial diseases. The present review discusses the diagnosis of medical diseases using dental panoramic radiographs, the diagnostic significance of computed tomography (CT) including multi detector CT (MDCT) and cone-beam (CB) CT, the application of mag-netic resonance imaging (MRI) for various kinds of oral-related diseases, and computer simulations for dental implant and orthognathic surgery planning using data of helical CT images. The usefulness of ultrasonography (US) for viewing surface soft tissues such as salivary glands, tongue, and lymph nodes, and the advantages and limitations of positron emission tomography (PET) with fluorine-18-labeled fluoro-2-deoxy-D-glucose (18FDG) are also described.

Background Dentists need to be aware of the relationship between malignancies and paresthesia or complete loss of sensation in a jaw segment. In particular, dentists should be aware of numb chin syndrome (NCS) and its clinical manifestations, as well as the limitations of using panoramic radiographs to detect the causative malignancy. Case Descriptions The authors report two cases of paresthesia in the mental region. No lesions were readily apparent on the patients' panoramic radiographs. To exclude the presence of disease in the mandible that could have been responsible for the NCS, the authors obtained computed tomographic (CT) images. They identified metastases to the mandible from primary malignant tumors elsewhere in the body. Clinical Implications To prevent misdiagnosis of NCS, dentists need to be aware of the clinical manifestations of NCS, the need for CT imaging, the shortcomings of panoramic radiographs and the value of obtaining detailed and accurate medical and dental histories from patients.

The aim was to evaluate the utility of dynamic magnetic resonance (MR) sialographic images as a diagnostic tool for patients with xerostomia as chief complaint.Various parameters of dynamic MR sialographic images from 40 healthy volunteers were compared with those from 28 patients having dry mouth as chief complaint. Dynamic MR sialographic images were acquired using a 1.5-T full-body MR system and 2-dimensional fast asymmetric spin-echo (2D-FASE) sequences. Acquisition of the optimal section using 2D-FASE sequencing with single-section acquisition of thick sections was repeated every 30 s before and after a few drops of 5% citric acid was placed on the tongue. Student t test was used to examine differences between the healthy volunteer and patient groups regarding the maximum area of salivary gland ducts before and after citric acid stimulation.The maximum area of the detectable ducts in the patient group was significantly smaller (P0.001), whereas the change in detectable duct area was significantly lower (P0.001).This study suggests that dynamic MR sialographic images and data can be useful in the diagnosis of patients with dry mouth as chief complaint.

我々は歯科放射線科・放射線部の本学附属病院に於ける役割を把握するため10年程度のスパンで外来患者数ならびに画像検査件数の推移について報告してきた．歯科疾患は硬組織に関連するものが大半を占めるが，歯科医師の知識向上と歯科医療の進歩により，軟組織病変に対するアプローチも増加した．九州歯科大学附属病院は平成11年7月に新築され，当科も当時最新鋭機種である1.5 Tesla全身用MRI装置とヘリカル撮像可能なX線CT装置を導入した．そこで，今回は附属病院の大きな変貌の中で本診療科の役割・存在意義の変化を正確に認識するため調査研究を行った．平成7年4月1日から平成19年3月31日迄の12年間に本学付属病院を受診し，当科において画像検査を受けた患者を調査対象とし，その画像検査件数を調査した．九州歯科大学附属病院が新築された平成11年度は病院全体の患者数が著しく増加すると共に本診療科の患者数も増加した．それに伴い，ほぼ全ての撮影法で件数の増加が認められた．MRI検査の撮影件数は導入以後著しく増加している．顎骨内に発症した疾患はX線CTによる検査がなされ，軟組織に発症したものはMRI検査がなされていたという結果からは，教科書等に記載されているX線CT検査とMRI検査の有効性を本学附属病院の歯科医師が理解し，適切な判断をなしているものと考える．X線CT及びMRI検査に対する他病院からの依頼数は年々増大傾向を示し，特に歯科用インプラントの術前検査は5年前より倍増している．この背景には，近年の歯科医院が歯科用インプラントの埋入に積極的になっていることが挙げられ，今後は更に増加していくことが予想される．一方で，当科のX線CT検査後のデータは市販のフリーソフト等で確認することができず，この点は大きな問題点であり早急の対応を考えているところである．

Summary Objective A gender difference in the unstimulated whole saliva flow rate (UWSFR) may be due to a difference in the sizes of the salivary glands. In this study, we investigated the relationships among the UWSFR, gland sizes and body sizes of healthy young adult males and females. Design Unstimulated whole saliva was collected for 5 min by the spitting method in 50 healthy young adults, and the flow rate of the saliva was measured. Heights and weights were measured, and body mass indices (BMI) were calculated. The sizes of the salivary glands were measured by use of a magnetic resonance imaging technique. Results Parotid and submandibular gland sizes and flow rates in females were significantly smaller than those in males, as were also the weights, heights and BMI. In both males and females, there were significant positive correlations between gland sizes and the flow rates, weights and BMI. The variations of the flow rates were reduced by standardizing them with gland sizes, weights and BMI. Conclusions These results suggest that the lower UWSFR in females as compared with males is due to the smaller gland sizes due to the smaller body sizes.

Summary Objective The aim of this study was to examine the relationships between gland sizes and the flow rate and composition of the unstimulated whole saliva in humans. Design In 28 healthy young adults, the sizes of the three major salivary glands were estimated by use of a magnetic resonance (MR) imaging technique. Unstimulated whole saliva was collected for 5 min by the spitting method, and the flow rate and the concentrations of total protein, Na + and K + and pH were measured. Results The estimated sizes of the parotid and submandibular glands showed a significant positive correlation with the flow rate and the secretion rate of total protein in the unstimulated whole saliva, but that of the sublingual glands did not. Concerning the concentrations of Na + and K + and pH, there were no correlations with the salivary gland sizes. Conclusions The results suggest that the larger the sizes of the parotid and submandibular glands, the faster the fluid flow and protein secretion rates in unstimulated whole saliva.

Objective To evaluate a proposed technique for the 3-dimensional (3D) detection of hemangiomas, including vascular malformation and their feeding arteries, in the head and neck. The new technique combines phase-contrast magnetic resonance angiography (PCMRA) without contrast medium and 3D fast asymmetric spin-echo (FASE) sequences. Methods The technique was applied to 3 patients having hemangiomas in the head and neck region. In 1 patient the image obtained with the proposed technique was compared to that obtained by standard contrast angiography. Results In all 3 patients, the 3D presence of the hemangiomas and the feeding arteries were well defined in images created by the proposed technique. Additionally, the characterization of the hemangioma's 3D structure and distribution of the feeding arteries coincided with those observed using contrast angiography in the case for which contrast angiography was also performed. Conclusions Preliminary experience shows that the proposed technique combining 3D-FASE and 3D-PCMRA is useful to visualize both the 3D structure of hemangiomas and to identify the 3D distribution of the feeding arteries without using contrast medium.

Objective To evaluate the utility of magnetic resonance (MR) cisternography using 3-dimensional (3D) fast asymmetric spin-echo (FASE) sequences with multiplanar reconstruction (MPR) for detection of the sites of neurovascular compression (NVC) in patients with trigeminal neuralgia. Study design Both MR cisternography with 3D-FASE sequences and MR angiography (MRA) were performed on 150 patients with clinical signs and symptoms that suggested trigeminal neuralgia. Results from the original MR cisternography with 3D-FASE sequences, the original MRA, and 4 reformatted images were used for interpretation. Images with inversion between black and white were used from the MR cisternography with 3D-FASE sequences to evaluate NVC. A diagnosis of NVC was made from the presence of vascular contact with the trigeminal nerve at the root entry zone (REZ) and the nature of the involved vessels. For the patients with NVC detectable on 3D-FASE or MRA images, the relationship between the clinically manifested regions and the NVC sites was also evaluated. Results Of the 150 patients evaluated, 89 were deemed to have NVC. Of these 89 patients, 3 underwent surgery that identified the artery that was involved with the trigeminal nerve. The correlation between the clinically manifested regions and the NVC sites was significantly detectable using both 3D-FASE images and MRA in 89 patients with detectable NVC. The correlation coefficient using 3D-FASE imaging was a little higher than that using MRA. Of the 61 patients deemed not to have NVC, 6 were found to have brain tumors that invaded the root entry zone of the trigeminal nerve. However, the remaining 55 patients had no identifiable cause for trigeminal neuralgia. NVC was found in the asymptomatic side in 27 (18%) of the 150 patients with trigeminal neuralgia using MR cisternography with 3D-FASE sequences. Conclusions The technique of MR cisternography using 3D-FASE sequences with MPR is more accurate and useful than MRA for detection of the site of NVC in patients with trigeminal neuralgia. Patients with trigeminal neuralgia should be further examined using MR imaging to rule out a brain tumor. Radiologists should understand that a few subjects with no symptoms could show NVC with MR cisternography.