Prevalence of Posterior Disc Displacement of the Temporomandibular Joint in Patients with Temporomandibular Disorders : A Systematic Review and Meta-Analyses

Aims: To assess the prevalence of posterior disc displacement (PDD) in patients with temporomandibular disorders (TMD) through a systematic review of the literature and meta-analysis, as well as to assess features associated with PDD such as chief complaint, signs and symptoms, morphologic condyle and disc alterations, and PDD management. Methods: A systematic literature search was performed in the US National Library of Medicine’s PubMed/MEDLINE and Cochrane Library databases to identify all peer-reviewed, English-language manuscripts related to PDD. A critical appraisal checklist provided by the Joanna Briggs Institue (JBI) for studies reporting prevalence data was used to assess the quality of the included manuscripts. A meta-analysis was conducted using software MetaXL 5.3 (EpiGear International Pty Ltd) add-in for Microsoft Excel. Pooled prevalence and 95% confidence intervals (CIs) were calculated using the software. Heterogeneity of the included studies was assessed using the Higgins I2 test and Cochran’s Q (with P value; < .05 was considered significant). Results: A total of 21 articles were selected for qualitative data synthesis: 2 case reports, 14 observational studies, and 5 studies that reported PDD in various conditions. Quantitative data analysis was performed for the 14 observational studies, of which 13 reported prevalence with respect to the number of joints affected and 9 reported prevalence with respect to the number of patients affected. The overall pooled prevalence of PDD for the number of joints affected was 0.7% (95% CI: 0.005 to 0.008). The pooled prevalence of PDD for the number of patients was 0.9% (95% CI: 0.007 to 0.011). PDD was found to be associated with osseous changes, including changes in the morphology of the condyle, disc, and articular eminence; osseous abnormalities (erosion, osteophytes); and joint effusion. Conclusion: This meta-analysis showed a very low prevalence rate of PDD in TMD patients. The limited literature did not allow conclusions to be drawn about the PDD-related features

コウクウガン ケイブ テンイ リンパセツ ノ ケンシュツ ニ タイスル チョウオウパ サンジゲン イメージング ノ ユウヨウセイ

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

Dental students’ levels of understanding panoramic

Background/purpose: 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. Materials and methods: 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: , , and to compare correct answer rates. Results: 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 and , 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 , such as the dorsum of tongue, middle and inferior nasal conche, and middle and inferior nasal meatuses, were also lower. Conclusion: These results indicate the necessity of improving educational approaches for regions with lower rates of correct answers

スパイラル CT オ モチイタ ガクカンセツ ノ サンジゲン ヒョウカホウ

Three-dimensional (3-D) image reconstructed from Computed Tomography (CT) data is an ef>cient method to evaluate temporomandibular joint (TMJ) morphologically. Even the 3-D image reconstructed from spiral CT data has some distortion, typically along to the table feed direction, very few studies were reported about accuracy of reconstructed 3-D image size. The purpose of this research was to evaluate the distortion on 3-D image reconstructed with spiral CT (Somatom Plas4, Siemens Co, Germany) quantitatively. We used three imaging targets, eight ceramic balls placed at corners of cubic frame, a calibration cube that has the CT value nearly equal to cortex bone of human dried mandibular head. We evaluated relation between a threshold level of CT image processing and reconstructed 3-D image size with a custom-made computer program. CT data of ceramic balls clari>ed changes of the reconstructed image, -0.215mm for table feed direction and less than ±0.006mm for the other directions. The calibration cube was used for the arrangement of optimal scanning condition (reconstruction mode, collimation, reconstitution interval) and evaluation of reconstructed image size. The distortion of the image was +0.207mm for table feed direction and less than +0.029mm for the other directions. Changes of dried skull TMJ image reconstructed with the optimal scanning condition were -1.463mm for lateral direction of the condylar head, -0.956mm for back and forth direction and -0.580mm for table feed direction. Results of this research suggested that the level of the 3-D image distortion was mostly affected with the scanning condition. And the size of 3-D image was susceptible to the threshold level of CT image processing. Consequently, we think that the standardization of scanning condition should be concerned for the quantitative evaluation of 3-D TMJ image using CT data

現行の口内法デジタルX線撮影システム間の薄い対象物及び厚い対象物におけるコントラストの違いの評価

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 ( < 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 ( < 0.001) but was inferior to it regarding the CNR ( < 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

ガク カンセツショウ カンジャ ニオケル MR ガゾウ ショケン ト リンショウ ショケン ノ ヒカク ケントウ

Two hundred eighteen (28.4%) of 768 patients with temporomandibular disorders (TMD), who visited the Clinic for Temporomandibular Disorders, Tokushima University Medical and Dental Hospital during the period of January 2006 through December 2007, were examined using magnetic resonance (MR) imaging. The present study assessed clinico-statistically the correlation between MR images and the clinical findings of 157 patients with complete registered data in our TMD reporting system. The following findings were obtained: 1. MR imaging showed anterior disk displacement in 125 joints (67.9%), rotational disk displacement in 45 joints (24.5%), and sideways disk displacement in 13 joints (7.1%). 2. Joint effusion (JE) was found in 42.7% of 157 patients; 48.0% in females and 23.5% in males. In addition, anterior or rotational disk displacement was observed in 97% of patients with JE. Furthermore, condyle bone change was significantly higher in joints with than without JE. 3. The appearance of JE was significantly higher on the symptomatic side than the asymptomatic side, but tenderness of the temporomandibular joint (TMJ) area or the value of the visual analog scale (VAS) regarding pain and problems in daily life was not related to the presence of JE

コウクウ ガク ガンメン アクセイ シュヨウ ノ エンカク テンイ ヒョウカ ニオケル クカンブ CT ケンサ ノ イチズケ

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