Agreement between Research Diagnostic Criteria for Temporomandibular Disorders and magnetic resonance diagnoses of temporomandibular disc displacement in a patient population

The aim of this work was to evaluate the agreement between the clinical Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) examination and magnetic resonance (MR) findings of temporomandibular joint (TMJ) disc position abnormalities in a sample of clinically symptomatic patients, recruited from a population seeking TMD treatment. Two-hundred and thirty-two TMJs of 116 patients were evaluated to detect disc position abnormalities by means of a standardized clinical assessment according to RDC/TMD guidelines and MR performed blind by a radiologist. The overall kappa value for agreement between clinical examination according to RDC/TMD classification system and MR imaging for assessment of the disc-condyle relationship was fairly good (K=0.63). The kappa values for the agreement between RDC/TMD and MR diagnosis of disc displacement with reduction (DDR), disc displacement without reduction (DDNR) and normal disk position were 0.69, 0.57, and 0.61, respectively. The observation that clinically predicted cases of DDR and DDNR show good to excellent agreement with MR findings, and the potential MR over-diagnosis of DDR and DDNR in the absence of clinical symptoms, support the usefulness of a standardized examination conducted by a trained investigator in the evaluation of patients with TMD.     

A comparison of micro-CT, microradiography and histomorphometry in bone research

OBJECTIVE: Intraobserver reliability and agreement were determined for microradiography (MR), micro-computed tomography (microCT) and histomorphometry (HM). These three modalities were compared for quantitative measurements of bone formation and graft modelling in rat mandibular defects and grafts. DESIGN: Twelve rats were randomly selected from a larger experiment, evaluating bone formation in rat mandibular defects and bone modelling in grafts. Twelve lateral microradiographs were taken of the grafts. microCT images were obtained from all defects and grafts (24 specimens). Defects and grafts were cut perpendicularly through their centre. Microradiographs, microCT images and histological sections were obtained from the resulting 48 specimens. New bone volume and graft volume were measured using image analysis software on MR and microCT images. Defect width and graft width were measured using images from HM, MR and microCT. The results were compared to each other. RESULTS: The intraobserver reliabilities for the measurements of new bone volume by microCT, and the measurement of graft modelling by MR and graft volume by microCT were high. The differences between MR, HM and microCT were larger in defect width measurements than in graft width measurement. MR measured smaller defects than HM and microCT. The 95% confidence interval was larger in defect width measurements compared to graft width measurements. CONCLUSIONS: The methods of MR and microCT image analysis are reliable but preferably should be used in combination as to obtain valid conclusions. HM, MR and microCT for graft widths measurements showed more agreement than for defect width measurements. MR appears to overestimate bone formation.     

MR angiography of the TMJ in asymptomatic volunteers

To evaluate the vascular anatomy of the temporomandibular joint (TMJ) and surrounding soft tissue non-invasively, we applied magnetic resonance (MR) angiography for delineating the arterial architecture around the TMJ. MR angiograms of the left and right TMJs in asymptomatic volunteers were obtained using 3D/Time-of-flight (TOF) (First Field Echo, TR/TE/FLIP=46ms/6.8ms/17^o) with intravenous contrast. These MR angiograms were compared with experimental angiograms of human TMJ autopsy specimens in order to identify each of the branches of the arteries on the MR angiograms. This study enabled the depiction by MR angiography of arterial vessels around the TMJ region to some degree. In conclusion, MR angiography appears promising as a non-invasive tool to evaluate the vascular anatomy of the TMJ.     

颞下颔关节磁共振FIESTA动态成像的诊断价值

目的:探讨颞下颌关节(TMJ)磁共振FIESTA动态成像的诊断价值.方法:对40例患者80侧TMJ进行常规静态磁共振扫描和斜矢状位FIESTA动态磁共振扫描.由2名医师分别对每侧TMJ FIESTA动态扫描时关节盘的位置、髁突的骨质改变和关节腔积液情况进行诊断,并与常规静态磁共振扫描诊断结果进行比较.结果:80侧TMJ磁共振FIESTA动态图像中,对关节盘移位的诊断,72侧与静态磁共振扫描结果相符,准确率为90％;对髁突骨质改变和关节腔积液的诊断,所有病例与静态磁共振结果完全相符,准确率达100％.结论:TMJ磁共振FIESTA动态图像诊断颞下颌关节内紊乱(TMJID)具有一定价值,但单凭动态检查结果不够全面,必须与常规静态磁共振扫描相结合.     

Magnetic resonance imaging findings of internal derangement in temporomandibular joints without a clinical diagnosis of temporomandibular disorder

The purpose of this study was to assess the prevalences of magnetic resonance (MR) imaging findings of internal derangement (ID) in temporomandibular joints (TMJs) without a specific clinical diagnosis of temporomandibular disorder (TMD), and to investigate whether in this TMJ group the variable of pain may be linked to MR imaging findings of ID. The study comprised 109 patients, who were assigned a clinical uni- or bilateral TMJ-related diagnosis of 'absence of TMD'. Bilateral sagittal and coronal MR images were obtained subsequently to establish the prevalence of TMJ ID. An MR imaging diagnosis of ID was found in 99 (55.9%) of the 177 TMJs investigated. About 30.3% of the closed mouth-related TMJ positions characterized by disc displacement presented with anterior disc displacement, while 27.3% had anterolateral and 25.3% anteromedial disc displacement. Analysis of the data revealed the presence of TMJ pain to be associated with significantly more MR imaging diagnoses of disc displacement without reduction than disc displacement with reduction (P < 0.05), while there was no significant difference in the prevalences of ID and those of absence of ID (P > 0.05). Using chi-square analysis, no significant relationship was found between the presence of TMJ pain and the MR imaging diagnosis of TMJ ID (P=0.93). Use of the kappa statistical test indicated poor diagnostic agreement between the presence of TMJ pain and the MR imaging diagnosis of ID (kappa=0.01). The results suggest TMJs with a clinical diagnosis of 'absence of TMD' to be associated with a high rate of IDs, while in these instances the clinical variable of TMJ pain may have no effect on prevalences of MR imaging diagnoses TMJ ID. The data confirm the aspect of clinical diagnostic criteria as an unreliable instrument in predicting MR imaging diagnoses of TMJ ID.     

Studies on oral health in mentally retarded adults

During the last decades, a new policy involving normalisation, integration, equality and deinstitutionalisation of mentally retarded (MR) individuals has been accepted in Sweden. Consequently, many institutions have been closed and an increased number of people with MR are now integrated into the Swedish community. The general aim of this thesis was to investigate if a greater degree of independence for MR adults influenced the prevalence of oral diseases. MATERIAL AND METHODS: The caries incidence and prevalence, number of remaining teeth, incidence of tooth mortality and interproximal bone loss were investigated in a group of MR adults, aged 21-40 years, all with protracted, regular preventive dental care. The studied variables were related to living arrangements and degree of MR, and were followed during 8.5 years (Papers I, II and VI). Incidence and reasons for tooth mortality were studied during 10 years in institutionalised MR individuals (Paper III). In connection with the closing-down of an institution for MR adults, the changes of oral hygiene habits, sucrose intake and oral microbiological flora were studied in the new integrated living (Papers IV and V). RESULTS: Less restrictive living arrangements and mild forms of MR were correlated to a high caries prevalence in persons with MR. After 8.5 years, the caries incidence had decreased in all subjects, but persons with mild MR and those who lived integrated still had a higher caries prevalence than other MR adults. With the exception of subjects with Down syndrome, the interproximal bone loss during 8.5 years was similar or lower compared to normal Swedish populations. Institutionalised MR subjects had lost an average of 3.72 teeth during 10 years. Periodontitis was the main reason for tooth mortality. Persons who cooperated well with dental treatment and those who used neuroleptics lost fewer teeth during the 10-year period compared to other MR individuals. The proportion of subjects with high levels of mutans streptococci and subjects who showed growth of P. intermedia/P. nigrescens decreased after deinstitutionalisation, and less subjects consumed sucrose frequently. The oral hygiene routines, and the levels of lactobacilli, P. gingivalis and A. actinomycetemcomitans were not influenced by the change in living arrangements. A simplified saliva sampling method, involving licking directly on the bacteria culture, was developed to count lactobacilli in saliva when delivering whole saliva was impossible. CONCLUSIONS: Less restrictive living and a mild degree of MR were correlated to a high caries prevalence. Subjects with poor ability to cooperate with dental treatment and those with Down syndrome have an obvious risk of deteriorated oral health. However, compared to normal Swedish populations, the MR subjects studied in this thesis had, after several years of regular dental care, satisfactory oral health.     

A comparison of imaging techniques with surgical experience in orbital injuries: A prospective study

The aim of the study is to compare the effectiveness of computerised tomography (CT) and magnetic resonance (MR) imaging in diagnosing herniation and entrapment of orbital soft tissues in orbital fractures. 15 consecutive patients with clinical signs and symptoms of medial orbital wall injury were examined with CT and MR. The data were subsequently compared with the findings of the surgical exploration with regard to the extent of the wall fractures, the presence of soft tissue herniation and its entrapment. CT and MR were equally accurate in demonstrating or excluding orbital wall fractures but both modalities slightly underestimated their incidence. CT and MR underestimated the actual incidence of soft tissue herniation and entrapment when compared with the surgical findings but the extent of soft tissue herniation and entrapment were demonstrated more clearly by MR than by CT scanning. MR imaging when available should therefore be used as the initial imaging modality and CT held in reserve for confirmation as positioning in the MR unit is easier and more comfortable for recently injured patients who may well have other injuries.     

Characteristic findings of adenoid cystic carcinoma on MR imaging and differentiation from squamous cell carcinoma

Ten patients with adenoid cystic carcinoma and 49 with squamous cell carcinoma confirmed by aiopsy were evaluated. In these patients, malignant tumors were suspected with clinical progressions and clinical symptoms. The purpose of this study was to analyze and discuss the characteristic findings on MR imaging of adenoid cystic carcinoma in the head and neck, and to examine the usefulness of MR imaging in the differentiation between adenoid cystic carcinoma and squamous cell carcinoma. The characteristics on MR imaging of adenoid cystic carcinoma are a high signal intensity on T2-weighted images, marked enhancement by Gd-DTPA, and a capsular structure. All cases of recurrent adenoid cystic carcinomas also showed upward extension. We consider that the high signal intensity on T2-weighted images, the marked contrast enhancement and the capsular structure in MR imaging can be useful in differentiating adenoid cystic carcinoma and squamous cell carcinoma.     

口腔颌面部恶性肿瘤单体素氢质子磁共振波谱的初步研究

目的探讨用单体素氢质子磁共振（^1H MR）波谱诊断口腔颌面部软组织恶性肿瘤的可行性。方法回顾分析42例经^1H MR检查并经病理证实为软组织恶性肿瘤的病例。^1H MR波谱空间定位采用点分辨波谱法，回波时间144ms。以肿瘤内胆碱化合物（化学位移为3．2×10^-6）的检出为评价标准。结果42例恶性肿瘤中，检出胆碱化合物者37例，包括15例鳞状细胞癌，9例涎腺癌，13例肉瘤和恶性淋巴瘤。结论单体素^1H MR波谱能为口腔颌面部软组织恶性肿瘤的诊断提供有益信息。多数恶性肿瘤以含胆碱化合物为特点，其中肉瘤和恶性淋巴瘤内胆碱化合物的检出高于上皮性癌。     

Relationship between jaws and the masseter muscle by superimposing MR images on the cephalogram

The purpose of this study was to observe the morphological relationship between maxillofacial skeleton and masseter by superimposing the masseter image constructed by MR image scanning on the cephalogram. Sixteen subjects with different mandibular plane angle were examined in this study. Cephalogram and MR images of each subject were taken, and the images were input to a computer by using a digitizer. The areas of masseter were selected in each MR scan image which were projected to the mid-sagittal layer of the MR scan images. The synthesized image of cephalogram and masseter was obtained by completely superimposing sagittal images of the masseter with the mid-sagittal-plane MR image on the cephalogram. The inclination of masseter was determined by the center of gravity on the cross-section of masseter. These synthesized images of cephalogram and masseter showed various shapes of masseter according to different mandibular plane angle. The inclination of masseter had a close correlation with some skeletal parameters (mandibular plane angle, ANB, Y-axis, facial angle, saddle angle) of cephalometric analysis. The volume of the masseter also had a close correlation with skeletal parameters (mandibular plane angle, gonial angle, Y-axis). These results revealed that morphometric analysis using synthesized images of cephalogram and masseter is useful, and that the inclination and the volume of masseter may have an influence on the shape of the mandibular bone and its vertical and anteroposterior development.     

Simple bone cyst: A discrepancy between magnetic resonance imaging and surgical observations

OBJECTIVE: The purpose of this study was to compare magnetic resonance (MR) imaging and surgical observations of fluid in simple bone cysts. STUDY DESIGN: Findings during MR imaging of 7 simple bone cysts were compared with surgical observations 1 day or 1.8 months (mean) after MR imaging. RESULTS: All MR images showed cavities filled with fluid. In 2 patients operated on the day after the imaging, surgical observations were in accordance with the MR findings. At surgery 1.8 months after the MR examination, 4 cavities were found to be empty and 1 cavity contained only a minor amount of fluid. CONCLUSION: A discrepancy between MR imaging and surgical observations of fluid in simple bone cyst cavities was observed that might be dependent on the time between the observations, indicating that a fairly rapid absorption of fluid might occur or that the amount of fluid in a simple bone cyst can vary for unknown reasons.     

A case of schwannoma in the tongue diagnosed with enhanced magnetic resonance image

We encountered a case of schwannoma of the tongue in a 74-year-old man, who complained chiefly of contact pain in an ulcer in the left sublingual region. Although by computed tomography we could not differentiate the lesion as a cyst or tumor, with magnetic resonance (MR) imaging we diagnosed a benign tumor on the basis of lesion enhancement. Axial and coronal MR imaging revealed the three-dimensional location of the lesion. This case showed that enhanced MR imaging is useful for the differential diagnosis of a benign tumor in the oral cavity.     

Magnetic resonance imaging in dentistry

MR imaging has found a place in the imaging sciences. These images are unique in that no ionizing radiation is used, the same tissues may or may not have different appearances with different machine settings, a unique set of terms is used to describe the findings in the images, and these findings can be analyzed with the view of obtaining more diagnostic information not readily available with any other imaging modality. Cases have been presented to help demonstrate differences in T1-weighted and T2-weighted sequences as well as the value of contrast material. Additionally, plain film and CT views were included so that they may be contrasted with the MR images. The role and application of CT versus MR imaging has been further discussed and illustrated by Nortjé and van Rensburg. A typical temporomandibular joint case has also been presented. In the future, it is hoped that clinicians will refer more patients for MR imaging so that diagnoses can be made more accurately with analytic software.     

合格伦综合征磁共振涎腺造影图像分析

目的：分析舍格伦综合征患者的腮腺磁共振涎腺造影表现、特点及应用价值。方法：应用1．5T超导型全身磁共振扫描仪对32例舍格伦综合征患者进行磁共振涎腺造影检查，获得自旋回波磁共振涎腺造影，对其特点进行观察和总结。结果：在舍格伦综合征患者磁共振成像中可看到点状、球状、腔状及破坏性表现，少数有正常的主导管和分支导管表现；无造影检查所见主导管层状或葱皮状。结论：磁共振涎腺造影可客观、清晰地反映舍格伦综合征患者腮腺主分支导管、腺泡病变，可作为诊断舍格伦综合征的依据之一。     

MR imaging of maxillomandibular lesions

This paper addresses maxillomandibular lesions including cyst, tumor and osteomyelitis in terms of their general features and discusses the use of MR imaging techniques, interpretation of images and their characteristic findings. MR imaging of odontogenic keratocyst improved the visualization of a cystic pattern, regularly thin walls, weak enhancement of cyst walls and inhomogeneous intensity of fluid contents. However, some of them could be misdiagnosed as mixed or solid patterns by non-contrast study alone. Ameloblastoma showed mixed solid and cystic components, irregularly thick walls, papillary projections, and marked enhancement of the walls. In mandibular osteomyelitis, MR imaging could give us more detailed information regarding residual activity of infection and the extent of involvement. MR findings were suggestive to differentiate between tumors and cysts and characterize many cystic entities in the maxillomandibular region.     

Effect of dental metals on magnetic resonance imaging (MRI)

The aim of this research was to examine the effects of metals used in dentistry upon magnetic resonance imaging (MRI). Ten disk-shaped samples of metals have been used in this study. Each sample has been set into a volunteer who had produced a normal MR image when tested. The subject was imaged in the sagittal, frontal and coronal plane with a 0.1T MRI device and results examined for MR defects.
Au, Ag, Au-Ag-Pd and amalgam produced no defect. Ni-Cr, Co-Cr and SUS304 expressed small amounts of MR defects, but SUS405, Pd-Co-Ni and Sm-Co expressed large defects. Those metals which create MR image degradation must not be used for fixed prosthesis or orthodontic devices both of which could easily be made from other metals. If the MR image degrading metals are to be used in dentistry, their application should be restricted to removable prosthesis.     

Effect of sodium hypochlorite and Ricinus communis solutions on control of denture biofilm: A randomized crossover clinical trial

Statement of problem

The prevalence of complete edentulism remains high in the elderly, and previous data have shown that poor denture hygiene is common among patients with edentulism.

Temporomandibular joint click sound and magnetic resonance-depicted disk position: Which relationship?

AIMS: The aim of this work was to evaluate the agreement between temporomandibular joint click sound and MR diagnoses of different disk positions. METHODS: One hundred ninety-four (N=194) patients seeking treatment for temporomandibular disorders at the TMD Clinic, Department of Maxillofacial Surgery, University of Padova, Italy, underwent a bilateral magnetic resonance of the temporomandibular joints. The presence of click sounds was clinically assessed according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and put into relation with different magnetic resonance (MR) diagnoses of disk-condyle position by means of permutation tests. RESULTS: The proportion of joints with reducing and non-reducing disk displacement which provided a click sound during the clinical assessment was similar (45.6% vs. 48.9%, respectively), while the prevalence of the two MR diagnoses in joints with click sound were strongly different (25.3% vs. 40.1%, respectively. Thus, the MR diagnosis which appears to be more positively associated with click sounds is disk displacement without reduction. CONCLUSION: There is a weak form of dependence between click and MR diagnosis, and the MR diagnosis of DDNR seems to be more positively associated with the presence of click sounds than the other categories, which did not show significant positive associations with click (i.e. there is negative association between click presence and normal disk position and no association between click presence and DDR joints.     

Clinical application of magnetic resonance sialographic 3-dimensional reconstruction imaging and magnetic resonance virtual endoscopy for salivary gland duct analysis.

PURPOSE: In a previous study, we showed that the new and fast sequence 3-dimensional (3D)-fast asymmetric spin-echo sequencing could be applied in magnetic resonance (MR) sialographic 3D reconstruction imaging of the parotid gland ducts and in producing virtual endoscopic views of the parotid gland with MR data. MATERIALS AND METHODS: In the present study, we examined the clinical application of these MR sialographic 3D reconstruction imaging and virtual endoscopy of the salivary gland ducts using MR data sets with 3D-fast asymmetric spin-echo sequencing. RESULTS: The MR sialographic 3D reconstruction images showed a complete view in the branch paths from all angles, and the MR virtual endoscopic views showed conditions in the endoluminal tracts of the large branches in 20 patients with salivary gland duct abnormalities, including Sj?gren syndrome, cyst, tumor, sialadenitis, and salivary calculi. CONCLUSION: The clinical use of MR sialographic 3D reconstruction imaging and MR virtual endoscopy for salivary gland ducts may enhance understanding of the 3D relationship between the ducts and the surrounding tissue, as well as the endoluminal circumstance within ducts. Possible future applications abound, and further investigation in this field is expected.     

The role of magnetic resonance imaging in the diagnosis and management of ameloblastoma

Magnetic resonance (MR) images of ameloblastoma are compared with computed tomographic (CT) images with the use of three parameters: artifact degradation, edge definition, and conspicuity. As a basis for comparison, MR imaging characterization of normal tissues is reviewed. The three cases studied demonstrate the importance of weighing heavily on MR for evaluation of tumor-normal tissue interface. MR generally proved to be superior to CT in the evaluation of recurrent disease because of its ability to differentiate tissues on the basis of their proton composition. CT images reflect the electron densities of tissues. Hence, interpreting inflammatory and postsurgical changes and differentiating them from neoplasm may be difficult. At the present time, familiarity with CT dictates that the MR evaluation complement and not substitute the CT evaluation.