徳島大学病院歯科放射線科における過去10年間のX線撮影件数・内容の分析

徳島大学病院歯科放射線科における過去10年間のX線撮影件数・内容の分析


Development of a Low Radioactivity Detection System Using a Digital Intraoral Radiography Detector (Imaging Plate)

デジタル口内法X線撮影検出器(イメージングプレート)を応用した低放射能検出システムの開発


Geometric assessment of imaging methods for complete denture form: Comparisons among cone-beam computed tomography, desktop dental scanning, and handheld optical scanning.


Changes in Image Examinations at the Department of Oral Radiology -The Number of Intraoral and Panoramic Radiographs-

歯科放射線科の撮影件数の推移 -口内法枚数と口外法件数-

After the computed radiography (CR) system was developed in 1986, it became possible to acquire, view and save digital images for medical diagnosis. Around that time, panoramic radiography was digitized by the CR system, but it was limited to large hospitals. From 1994, it has been digitized at large hospitals and dental clinics. We examined the changes in the number of intraoral and panoramic radiographs in dentistry, and based on the relationships among the numbers of radiographs, patients and dental operations, we discussed the clinical significance of digitization.
We extracted intraoral and panoramic radiography data, the number of dental operations and the number of patients from the database of Tokushima University Hospital from 2002 to 2017. Then, we extracted nationwide data from Statistics of Medical Care Activities in Public Health by the Ministry of Health, Labour and Welfare from 2002 to 2017.
As a result, although the numbers of patients and dental operations at Tokushima UniversityHospital have remained constant, the number of intraoral radiographs has decreased (72%), whereas the number of panoramic radiographs has increased annually since 2011 (131%). In addition, although the number of patients and nationwide insurance points increased in a different manner than that at Tokushima University Hospital, a decrease in the number of intraoral radiographs and an increase in the number of panoramic radiographs were noted across Japan. As panoramic imaging has been improved and adapted to different settings, panoramic radiography has been used instead of intraoral radiography, and it has been widely used in screening applications such as for perioperative patients. Although digitization is progressing, the analog images are still used (intraoral radiography analog rate, 29.7%, panoramic radiography analog rate, 12.4% in 2017).


咬合不全を伴った重度変形性顎関節症症例

咬合不全を伴った重度変形性顎関節症症例

Journal of the Japanese Society for the Temporomandibular Joint


Dental students' levels of understanding normal panoramic anatomy

In dentistry, panoramic radiography is an important examination technique. The Faculty of Dentistry at Tokushima University educates students about panoramic radiographic anatomical landmarks. The purpose of this study was to investigate differences in the understanding of each panoramic anatomical landmark among students. This study analyzed the results of 40 fifth- and 79 sixth-year faculty students who had taken a written examination to clarify their knowledge of anatomical landmarks in 28 panoramic radiographic regions. Anatomical landmarks were classified into 3 categories: <bone structure>, <soft tissue/air layer>, and <ghost images > to compare correct answer rates. The mean overall correct answer rate by the 119 students for the 28 regions was 53%. The rate did not vary between the 2 academic years. On comparison of the 3 categories, significant differences were only observed between <bone structure> and <soft tissue/air layer>, as the values for the latter were lower. Among the anatomical landmarks, the rates for the condylar head, hyoid bone, panoramic innominate line, styloid process, and nasopalatine line were higher, and those for ghost images of the contralateral nasopalatine line, the cervical vertebrae, mandibular foramen, mastoid air cell, and posterior pharyngeal wall were lower. The values for <soft tissue/air layer>, such as the dorsum of tongue, middle and inferior nasal conche, and middle and inferior nasal meatuses, were also lower. These results indicate the necessity of improving educational approaches for regions with lower rates of correct answers.


Time-course observation of patients with arthrosis of the temporomandibular joint on MRI

Patients with arthrosis of the temporomandibular joint are examined by MRI, but fewer cases are followed over time by performing MRI several times. The objective of this study was to investigate the presence or absence and types of changes in the structure of the mandibular condyle and articular disc on MR images over time in patients examined by MRI for the diagnosis of arthritis of the temporomandibular joint in order to clarify the usefulness of performing MRI several times.
 MR images for patients who underwent MRI several times based on the clinical diagnosis of arthrosis of the temporomandibular joint were analyzed.
 Twenty-three patients were examined by MRI twice or more. The shortest and longest intervals between the first and final examinations were 75 and 2,588 days, respectively, and the mean was 735 days. Changes in the bone structure of the mandibular condyle were noted on the first MRI in approximately 63 % and new changes were noted on the final examination in approximately 24 %. In addition, the articular disc position in the closed or open mouth had changed on the later examinationin approximately 15 %.
 Performing MRI several times along the clinical course was found to be useful to diagnose the disease stage, judge the treatment effects, and help predict the outcome in patients with arthrosis of the temporomandibular joint.


Numerical Evaluation of Image Contrast for Thicker and Thinner Objects among Current Intraoral Digital Imaging Systems.

The purpose is to evaluate the performance of current intraoral digital detectors in detail using a precise phantom and new method. Two aluminum step wedges in 0.5 mm steps were exposed by two photostimulable phosphor plate (PSP) systems-one with automatic exposure compensation (AEC) and the other without AEC-and a CCD sensor. Images were obtained with 3 doses at 60 kV. The effect of metallic material also was evaluated. The contrast-to-noise ratio (CNR) for thinner steps and the low contrast value (LCV) for thicker steps were obtained. The CCD system was the best under all conditions (P < 0.001), although the Gray value was sensitive to the dose, and the Gray value-dose relation varied greatly. The PSP system with AEC was superior to that without AEC for the LCV (P < 0.001) but was inferior to it regarding the CNR (P < 0.001). CNR and LCV in the PSP system without AEC were not affected by the metallic plate. Intraoral digital imaging systems should be chosen according to their diagnostic purpose. PSP system with AEC may be the best for detecting molar proximal caries, whereas the PSP system without AEC may be better for evaluating small bone regeneration in periodontal disease. The CCD system provided the best performance.


Availability of Japanese Government's supplemental texts on radiation reflecting the Fukushima Daiichi Nuclear Power Plant accident for elementary and secondary education from dental students' understanding

Following the Fukushima Nuclear Power Plant accident, the Japanese government created two supplemental texts about radiation reflecting the accident for elementary, middle school, and high school students. These texts were made to explain radiation and consequently to obtain public consent for the continuation of the nuclear program. The present study aimed to evaluate the appropriateness of the content of the texts and to collect the basic data on the level of understanding necessary to improve radiation education. Lectures on radiology including nuclear energy and the Fukushima accident were given to 44 fourth-year dental students in 2013. The questionnaire was administered in 2014 when these students were in their sixth-year. The survey was also administered to 40 first-year students and 41 fourth-year students who hadn't any radiology lectures. Students rated their level of understanding of 50 phrases used in the texts on a four-point scale (understanding = 3, a little knowledge = 2, having heard = 1, no knowledge = 0). Questions on taking an advanced physics course in high school and means of learning about radiation in daily life were also asked. The level of understanding of phrases in the supplemental text for middle and high school students was significantly higher among sixth-year students (mean = 1.43) than among first-year (mean = 1.12) or fourth-year (mean = 0.93) students (p < 0.05). Overall, the level of understanding was low, with scores indicating that most students knew only a little. First-year students learning about radiation from television but four-year and six-year students learning about radiation from newspaper scored significantly higher (p < 0.05). It was concluded that radiation education should be improved by using visual material and preparing educators to teach the material for improving the public's understanding of radiation use-especially nuclear power generation because the phrases used in the supplementary texts are very difficult for students to understand.


Analysis of articular disc morphology with closed and open mouth positions by magnetic resonance imaging in patients with temporomandibular disorders

顎関節症患者のMR画像による閉口位と開口位の関節円板形態分析


Creation of a dental X-ray unit with a contactless exposure control switch

A new dental radiographic unit (DXRU) with a contactless switch for adjusting exposure conditions and a foot-pedal exposure switch was developed to prevent bacterial or viral contamination from patients and was compared with a conventional DXRU with a panel push-button switch with respect to user friendliness. 45 fourth-year dental school students carried out intraoral radiography using both types of DXRU. Errors regarding dose shortages of X-rays were compared and a questionnaire completed. 22 (49%) of the 45 students failed to provide the correct radiographic exposure and the number of errors was 32 for the conventional DXRU, and 4 (9%) students failed to provide the correct radiographic exposure and the number of errors was 4 for our new DXRU, at the first stage (p < 0.001). At the second stage, the number of students who failed to provide the correct radiographic exposure and the number of errors decreased to 12 and 16, respectively, for the conventional DXRU (p < 0.05). 37 (82%) of the 45 students preferred our DXRU because of its contactless switch and the push-pedal exposure switch. These data suggested that our new contactless mechanism should be used for other DXRUs for contamination control.


口内法X線画像のための新しいDICOMファントムの実用化

口内法X線画像のための新しいDICOMファントムの実用化


Distance Measurement Accuracy of a Digital CCD Sensor Cephalometric System Comparison with a Conventional-type Computed Radiography Photostimulable Phosphor Cephalometric System

CCDセンサー方式セファロシステムによる距離測定精度 ーCRシステムを用いた従来型セファロシステムとの比較ー


Sonographic Appearance of Mucus Cysts of the Lip

口唇部粘液嚢胞の超音波画像所見

The ultrasonographic features of 12 histologically proven mucus cysts in the lip were reported. All mucus cysts were of submucosal mass with a smooth border. Ten of 12 cysts contained an anechoic area. Among the 12, 11 had an adjacent hypoechoic zone with blood flow. There were reactive sclerotic or edematous changes outside the cyst wall, caused by the partial extravasation of saliva. This finding was exclusively observed in mucus cysts and would help in differential diagnosis, because most of the cysts with extravasation were difficult to distinguish from solid tumor by physical examination alone.


The Utility of Three Dimensional Ultrasonographic Imaging for Detecting the Cervical Lymph Node Metastasis with Oral Cancer

口腔癌頸部転移リンパ節の検出に対する超音波三次元イメージングの有用性

Three dimensional ultrasonographic imaging was performed for the cervical lymphadenopathy. Forty lymph nodes with suspicion of metastatic lymphadenopathy out of 20 patients with oral cancers were served for the present study. We could not judge the presence/absence of the metastasis by routine B mode or power Doppler imaging alone. Out of the 40 lymph nodes, 18 metastatic lymphadenopathies were proved histopathologically. Additionally, 11 lymph nodes out of 8 patients with nonspecific reactive lymphadenopathies were included as the control. The pattern of the circumferential blood flow of the lymph nodes was reviewed by the three-dimensional maximum intensity projection (3D MIP) view that was obtained from 3D power Doppler imaging. They were divided into 4 categories ; linear blood flow, mesh like blood flow, spotty blood flow and no circumferential flow. The spotty flow was almost exclusively found in the metastatic lymph nodes. Its accuracy, sensitivity and specificity, positive predictive value and negative predictive value for detecting metastatic lymphadenopathy were 0.73, 0.44, 0.95, 0.89, and 0.68, respectively. This spotty flow was situated at the marginal portion and/or around the lymph nodes by the analysis of the two-dimensional display. We could not differentiate whether it was arterial or venous flow. As the three dimensional sonographic imaging is the time-consuming technique compared to the routine B mode or power Doppler imaging, we cannot routinely perform it. However, it would play a supplementary role for detecting lymph node metastasis, especially if we cannot judge them by the two dimensional imaging alone.


Significance of Abdominal CT Examination for the Screening of Distant Metastasis of the Orofacial Malignancies

口腔顎顔面悪性腫瘍の遠隔転移評価における躯幹部CT検査の位置づけ

Abdominal CT examinations for the scouting of distant metastasis (DM) of orofacial malignant tumors were retrospectively evaluated, for the purpose of establishing the standard way of examination. Out of 159 patients with oral malignancies, 247 abdominal CT examinations were performed for the purpose of scouting DM. During the examination, intravenous contrast enhancement (CE) was performed in 166 examinations. DM were detected in 13 patients (8.2%). DM were found in 6 at administration, and 8 were late DM. Nine DM were detected out of 166 (5.4%) examinations with CE, and 5 were detected out of 81 (6.2%) examinations without CE. In detecting the DM, no improvement was found by CE. DM attacked lungs in 13, mediastinum in 3, liver in 2, paraaortic lymph nodes in 1, chest wall in 1, and vertebra in 1. Only 2 patients with DM were free from cervical metastasis, and the remainder was combined with cervical metastasis, regardless the status of the primary sites. Conclusions: Abdominal CT was useful for detecting DM. Intravenous CE was not necessary for scouting the DM. Patients with cervical metastasis had a high potential for developing DM.


An Investigation of Accidental Aspiration and Swallowing during the Dental Treatment at Tokushima University Hospital

徳島大学病院歯科診療部門における誤飲・誤嚥の実態調査

When an accident of aspiration or swallowing occurs during dental treatment, the patient would fall into severe clinical condition such as pneumonia, peritonitis, sepsis, and even death, unless a dentist immediately judges the patient's situation. As most dental material is radiopaque, radiography of a chest or an abdomen allows to see the accidental materials. From 1995 to 2002, 35 radiographic examinations were performed after the accidents at Tokushima University Dental Hospirtal. Mean of accidents was 4.4 cases a year. The incidence was 0.004% in the cumulative numbers of dental examinations. The location of accidental material on the radiography was clearly observed in 18 among 35 cases. Radiography of multiple times was performed 13 in 18 cases in order to confirm the excretion. In 5 cases, accidental materials were not confirmed to excrete. Furthermore, there were many cases in which clinical records about accidents were not described. Present findings indicate that it is necessary to detect precisely the location of accidental materials and that radiographic detection is very important.


新構想徳島大学医学部歯学部附属病院におけるHIS,RIS,PACS-モダリティ連携と歯科放射線科


Panoramic Radiography of the Temporomandibular Joint Part 5 --- A Study on Image Layer of Lateral Panoramic Temporomandibular Joint Projection

パノラマX線撮影装置を利用した顎関節撮影法 第五報 --- 顎関節側面パノラマ4分割撮影法における断層域の検討


Panoramic Radiography of theTemporomandibular Joint Part 4 --- Detectability of outline of the Temporomandibular Joint in Lateral Panoramic Temporomandibular Joint Projection

パノラマX線撮影装置を利用した顎関節撮影法 第四報 --- 顎関節側面パノラマ4分割撮影法における骨外形の出現度


パノラマX線写真による歯数の観察 --- 加齢と歯の喪失

パノラマX線写真による歯数の観察 --- 加齢と歯の喪失


The Position of the Condyle and the Disc in Temporomandibular Joint Dysfanction --- Comparison between Tomography and Magnetic Resonance Imaging

顎関節症患者の下顎頭位と円板位置 --- X線断層写真とMR画像の比較


Construction of Database about Report of Radiographic Examination of Temporomandibular Joint

顎関節X線検査報告書のデータベース化


日本人顎関節症患者のX線断層撮影による下顎頭の前頭面形態の分析

日本人顎関節症患者のX線断層撮影による下顎頭の前頭面形態の分析

Journal of the Japanese Society for the Temporomandibular Joint


Panoramic Radiography of the Temporomandibular Joint Part 2:A Study of Horizontal Optimum Angle of X-ray Beam to Mandibular Condyle

パノラマX線撮影装置を利用した顎関節撮影法 第二報 水平方向の至適X線入射角度の検討

The horizontal angle of x-ray beam projection to obtain an optimum anterior-oblique view of the mandibular condyle on a panoramic radiogram with least superimposition of the cranial base structures was examined. Eleven left temporomandibular joints from 11 dried human skulls were studied. Thirteen images were obtained for each joint, projected from 8° posterior to 52° anterior in 5° steps. The possible structures superimposing the condyle were the eminence from infratemporal crest to sphenoid spine, the eminence from articular tubercle to sphenoid spine, post glenoid process, anterior wall of the external auditory meatus, and mastoid process. None of the structures except mastoid process caused any problem in tracing the contour of the condyle. The part of the condyle with superimposition of the mastoid process was difficult to interpret, and extent of the part spread gradually as the projection angle increased. Nine out of 11 (82%) condyles were not superimposed with the mastoid process when a 30° anterior projection was adopted. This was considered to be the most suitable angle to obtain an anterior-oblique aspect of the mandibular condyle keeping good visibility.


顎関節症患者における下顎頭の経時的な骨形態変化に関する一考察

顎関節症患者における下顎頭の経時的な骨形態変化に関する一考察


放射線治療が影響したと考えられる開口障害を呈した一例

放射線治療が影響したと考えられる開口障害を呈した一例


機能に伴う顎関節骨形態の適合性変化 --- 下顎頭後面の陥凹について

機能に伴う顎関節骨形態の適合性変化 --- 下顎頭後面の陥凹について


The Development of the Dento^Maxillo-Facial Image Database and its Application to the Analysis of Dento-Maxillo-Facial Morphology

口腔領域画像データベースシステムの開発とその歯·顎·顔面形態計測分析への応用


日本の歯科学生とインドネシアの歯科学生・歯科衛生士学生における放射線に対する理解度とリスク認識との関係


口内法X線画像用DICOMファイルの規格化および歯科用Viewerの実用化

口内法X線画像用DICOMファイルの規格化および歯科用Viewerの実用化


2種類のデジタル口内法イメージングシステムによるコントラストの比較

2種類のデジタル口内法イメージングシステムによるコントラストの比較