Temporomandibular involvement in children and adolescents with juvenile idiopathic arthritis: a 2-year prospective cohort study.

This study aimed to clinically evaluate temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA) and the ability to identify and/or predict development of TMJ-deformities over time using cone beam computed tomography (CBCT). The predictive value of self-reported TMJ pain was also assessed. A prospective longitudinal cohort study comprising 54 children with JIA, 39 girls and 15 boys, was performed. All children had active disease at baseline, 50% with the subtype oligoarthritis. Repeated clinical orofacial and CBCT examinations were performed over a two-year period. At baseline, 39% had radiographic TMJ deformities (24% unilateral, 15% bilateral), at 2-year follow-up, 42% (p > 0.05). Both progressing and improving TMJ deformities were observed. An association was found between TMJ-deformities and self-reported TMJ pain at baseline (p = 0.01). Maximum unassisted mouth opening (MUO) was smaller for children with TMJ-deformities (p < 0.05). The prevalence of palpatory muscle pain was high (48-59%) but not predictive of development of TMJ-deformities. TMJ noises increased over time and crepitations were associated with TMJ-deformities (p < 0.05). In conclusion, in children with JIA, self-reported TMJ pain and dysfunction were common and predictive of TMJ deformities. TMJ deformities were associated with smaller MUO and palpatory TMJ pain as well as crepitations. Trial registration. ClinicalTrials.gov Protocol id: 2010/2089-31/2.

Temporomandibular joint pathologies: pictorial review.

In this pictorial review, an introductory paragraph emphasizes the significance of some anatomical aspects for optimal imaging of the temporomandibular joint (TMJ). The most frequent pathologies: internal derangement (ID) and osteoarthritis (OA) are comprehensively discussed and illustrated. Less common conditions: ID and OA-like changes in children and adolescents, idiopathic condylar resorption, inflammatory arthritis, and juvenile idiopathic arthritis are briefly discussed. A short paragraph on differential diagnostics in young patients is included followed by a brief comment on expansile lesions that occasionally may occur in the TMJ.

Imaging signs of temporomandibular joint osteoarthritis in an urban population of 65-year-olds: A cone beam computed tomography study.

BACKGROUND: Symptoms of osteoarthritis (OA) in the temporomandibular joint (TMJ) may vary and possible causes should be further explored, such as prevalence and characteristics of imaging features. OBJECTIVES: Investigate prevalence, gender differences and characteristics of imaging signs of TMJ-OA by cone beam computed tomography (CBCT) in a population-based sample of 65-year-old Oslo citizens. MATERIALS AND METHODS: 159 (86 women, 73 men) individuals randomly recruited from a cohort of 460 Oslo citizens were examined with CBCT. The TMJs were categorised as with imaging signs of OA, no OA or indeterminate for OA. RESULTS: CBCT signs of TMJ-OA were found in 35% of the 159 participants: 47% of the women and 22% of the men. CBCT signs of TMJ-OA were unilateral in two-thirds of the TMJs and characterised by articular surface flattening and condylar osteophytes. In almost all joints with bone erosive findings, bone productive findings were also found. Participants with and without CBCT signs of TMJ-OA showed no significant difference in TMD pain screener. Fourteen of the 159 participants (9%) had pain-related TMD and 12 (8%) had been in contact with health care services due to TMD. CONCLUSIONS: CBCT signs of TMJ-OA was common in this study group of 65-year-old Oslo citizens, found in every second woman and every fifth man. Articular surface flattening and bone productive changes, in particular condylar osteophytes, were the most frequent imaging features. Despite the high frequency of CBCT signs of TMJ-OA, few of the participants had pain-related TMD.

Management of Orofacial Manifestations of Juvenile Idiopathic Arthritis: Interdisciplinary Consensus-Based Recommendations.

Involvement of the temporomandibular joint (TMJ) is common in juvenile idiopathic arthritis (JIA). TMJ arthritis can lead to orofacial symptoms, orofacial dysfunction, and dentofacial deformity with negative impact on quality of life. Management involves interdisciplinary collaboration. No current recommendations exist to guide clinical management. We undertook this study to develop consensus-based interdisciplinary recommendations for management of orofacial manifestations of JIA, and to create a future research agenda related to management of TMJ arthritis in children with JIA. Recommendations were developed using online surveying of relevant stakeholders, systematic literature review, evidence-informed generation of recommendations during 2 consensus meetings, and Delphi study iterations involving external experts. The process included disciplines involved in the care of orofacial manifestations of JIA: pediatric rheumatology, radiology, orthodontics, oral and maxillofacial surgery, orofacial pain specialists, and pediatric dentistry. Recommendations were accepted if agreement was >80% during a final Delphi study. Three overarching management principles and 12 recommendations for interdisciplinary management of orofacial manifestations of JIA were outlined. The 12 recommendations pertained to diagnosis (n = 4), treatment of TMJ arthritis (active TMJ inflammation) (n = 2), treatment of TMJ dysfunction and symptoms (n = 3), treatment of arthritis-related dentofacial deformity (n = 2), and other aspects related to JIA (n = 1). Additionally, a future interdisciplinary research agenda was developed. These are the first interdisciplinary recommendations to guide clinical management of TMJ JIA. The 3 overarching principles and 12 recommendations fill an important gap in current clinical practice. They emphasize the importance of an interdisciplinary approach to diagnosis and management of orofacial manifestations of JIA.

Discrete Choice Experiment on a Magnetic Resonance Imaging Scoring System for Temporomandibular Joints in Juvenile Idiopathic Arthritis.

OBJECTIVE: To determine the relative importance weights of items and grades of a newly developed additive outcome measure called the juvenile idiopathic arthritis (JIA) magnetic resonance imaging (MRI) scoring system for the temporomandibular joint (TMJ) (JAMRIS-TMJ). METHODS: An adaptive partial-profile, discrete choice experiment (DCE) survey using the 1000Minds platform was independently completed by members of an expert group consisting of radiologists and non-radiologist clinicians to determine the group-averaged relative weights for the JAMRIS-TMJ. Subsequently, an image-based vignette ranking exercise was done, during which experts individually rank ordered 14 patient vignettes for disease severity while blinded to the weights and unrestricted to JAMRIS-TMJ assessment criteria. Validity of the weighted JAMRIS-TMJ was tested by comparing the consensus-graded, DCE-weighted JAMRIS-TMJ score of the vignettes with their unrestricted image-based ranks provided by the experts. RESULTS: Nineteen experts completed the DCE survey, and 21 completed the vignette ranking exercise. Synovial thickening and joint enhancement showed higher weights per raw score compared to bone marrow items and effusion in the inflammatory domain, while erosions and condylar flattening showed nonlinear and higher weights compared to disk abnormalities in the damage domain. The weighted JAMRIS-TMJ score of the vignettes correlated highly with the ranks from the unrestricted comparison method, with median Spearman's ρ of 0.92 (interquartile range [IQR] 0.87-0.95) for the inflammation and 0.93 (IQR 0.90-0.94) for the damage domain. CONCLUSION: A DCE survey was used to quantify the importance weights of the items and grades of the JAMRIS-TMJ. The weighted score showed high convergent validity with an unrestricted, holistic vignette ranking method.

Assessing the Reliability of the OMERACT Juvenile Idiopathic Arthritis Magnetic Resonance Scoring System for Temporomandibular Joints (JAMRIS-TMJ).

Contrast-enhanced magnetic resonance imaging (MRI) remains the most comprehensive modality to assess juvenile idiopathic arthritis (JIA)-related inflammation and osteochondral damage in the temporomandibular joints (TMJ). This study tested the reliability of a new JIA MRI scoring system for TMJ (JAMRIS-TMJ) and the impact of variations in calibration and reader specialty. Thirty-one MRI exams of bilateral TMJs were scored independently using the JAMRIS-TMJ by 20 readers consisting of radiologists and non-radiologist clinicians in three reading groups, with or without a calibrating atlas and/or tutorial. The inter-reader reliability in the multidisciplinary cohort assessed by the generalizability coefficient was 0.61-0.67 for the inflammatory and 0.66-0.74 for the damage domain. The atlas and tutorial did not improve agreement within radiologists, but improved the agreement between radiologist and non-radiologist groups. Agreements between different calibration levels were 0.02 to 0.08 lower by the generalizability coefficient compared to agreement within calibration levels; agreement between specialty groups was 0.04 to 0.10 lower than within specialty groups. Averaging two radiologists raised the reliability above 0.8 for both domains. Therefore, the reliability of JAMRIS-TMJ was moderate-to-good depending on the presence of specialty and calibration differences. The atlas and tutorial are necessary to improve reliability when the reader cohort consists of multiple specialties.

Efficacy and safety of intraarticular corticosteroid injections in adolescents with juvenile idiopathic arthritis in the temporomandibular joint: a Norwegian 2-year prospective multicenter pilot study.

BACKGROUND: Intraarticular corticosteroids (IACs) have been used to treat temporomandibular joint (TMJ) arthritis. However, prospective clinical studies with magnetic resonance imaging (MRI) scoring are lacking. The aim of this study was to examine efficacy and safety of a single IAC in the TMJ in adolescents with juvenile idiopathic arthritis (JIA) in a clinical setting. METHODS: In this Norwegian prospective multicenter pilot study 15 patients with JIA (mostly persistent oligoarthritis or RF negative polyarthritis categories) and a clinically and MRI-verified diagnosis of TMJ arthritis were treated with IACs and followed for 2 years. Demographics, systemic medication, general disease activity and outcome measures were recorded including a pain-index score and maximal incisal opening (MIO). Inflammation and bone damage scores were assessed, using two recently published MRI scoring systems with masked radiological evaluation. RESULTS: Among the 15 patients, 13 received a single IAC (5 bilateral), and 2 repeated IACs once unilaterally. Thus, the total number of IACs was 22. Median age was 15 years and the majority had an age not thought of as critical regarding mandibular growth retardation due to steroid injection. During the 2-year observation period systemic medication with disease modifying antirheumatic drugs (DMARDs) including biologics was initiated or adjusted in 10/15 (67%) patients. At the 2-months study visit after injection we observed a minimal improvement in MIO from median 44 (1st, 3rd quartiles; 36, 48) mm to 45 (43, 47) mm, p = 0.045 and decreased MRI mean additive inflammatory score from 4.4 ± 1.8 standard deviations (SD) to 3.4 ± 2.0, p = 0.040. From baseline to the 2-months follow-up pain improved in 6/11 patients but pain scores were not significantly improved. MRI-assessed damage increased in two patients with repeated IACs, and decreased in 3 patients but most of the patients were stable over the 2-year follow-up. Intra-rater repeatability of the MRI scoring system domains varied from poor to excellent. CONCLUSIONS: In this pilot study of predominately single IACs to the TMJ in combination with systemic treatment we observed improvement in MRI-assessed inflammation, mostly stable condylar bone conditions and minimal clinical improvement in adolescents with JIA and TMJ arthritis. No severe side effects were seen.

Improvement of bone-erosive temporomandibular joint (TMJ) abnormalities in adolescents undergoing non-surgical treatment: a longitudinal study.

OBJECTIVES: To investigate the longitudinal changes of the imaging temporomandibular joint (TMJ) characteristics in young patients with TMJ-related symptoms and treated with non-surgical methods. The severity of self-reported symptoms at follow-up was also investigated. METHODS: A cone beam CT (CBCT)/CT follow-up examination [median follow-up 4.1 (1.3-6.4) years] was performed in 22 patients with erosive TMJ abnormalities [baseline median age 16 (12-18) years]. Imaging characteristics were analyzed and the changes between the examinations were categorized as (A) improvement, (B) no change, or (C) worsening. Severity of follow-up symptoms was evaluated using Jaw Functional Limitation Scale (JFLS-8) and Graded Chronic Pain Scale (Grade 0-IV). Analyses were performed separately for left and right TMJ. Findings at baseline and follow-up were compared using McNemar test to account for dependencies. Changes in proportions of hard tissue findings between examinations were assessed using Wilcoxon signed ranks test. RESULTS: A significant reduction in the proportion of patients with erosive abnormalities was found [59.1%, 95% CI (36.4-79.3) %]. Baseline erosions improved in 9/12 (75%) right and 14/15 (93%) left TMJs. About half repaired; developed an intact cortical outline. Number of joints with osteophytes increased (right: p < 0.04, left: p < 0.003). New osteophytes were mostly found in joints with erosive findings. Low or no limitation of jaw function (Jaw Functional Limitation Scale) was found in 12/22 (55%) and no or low intensity of pain (Graded Chronic Pain Scale Grade 0 or I) in 19/22 (86%) at follow-up. CONCLUSION: We found a high potential for repair of erosive TMJ abnormalities. However, the patient series was small. The majority of patients assessed their symptom severity at follow-up as low.

The Role of Imaging in the Diagnosis of Temporomandibular Joint Pathology.

Diagnostic imaging is sometimes necessary to supplement the clinical findings in patients with suspected temporomandibular disorders (TMDs). However, the interpretation of pathology in the imaging findings is often complicated by the presence of similar findings in asymptomatic volunteers, as well as by the use of inadequate imaging techniques and poor image quality. This article focuses on these issues and gives guidance on the appropriate use of diagnostic imaging in patients with suspected TMD.

Imaging of temporomandibular joint abnormalities in juvenile idiopathic arthritis with a focus on developing a magnetic resonance imaging protocol.

Inflammation and damage in the temporomandibular joint (TMJ) often develop without clinical symptoms but can lead to severe facial growth abnormalities and impaired health-related quality of life, making early diagnosis of TMJ changes crucial to identify. Inflammatory and osteochondral changes detectable through magnetic resonance imaging (MRI) occur in TMJs of approximately 40% of children with juvenile idiopathic arthritis (JIA), and no other imaging modality or physical method of examination can reliably detect these changes. Therefore contrast-enhanced MRI is the diagnostic standard for diagnosis and interval monitoring of JIA. However the specific usage of MRI for TMJ arthritis is not standardized at present. There is a recognized need for a consensus effort toward standardization of an imaging protocol with required and optional sequences to improve detection of pathological changes and shorten study time. Such a consensus imaging protocol is important for providing maximum information with minimally necessary sequences in a way that allows inter-site comparison of results of clinical trials and improved clinical management. In this paper we describe the challenges of TMJ imaging and present expert-panel consensus suggestions for a standardized TMJ MRI protocol.

Toward Establishing a Standardized Magnetic Resonance Imaging Scoring System for Temporomandibular Joints in Juvenile Idiopathic Arthritis.

OBJECTIVE: The temporomandibular joints (TMJs) are frequently affected in children with juvenile idiopathic arthritis (JIA). Early detection is challenging, as major variation is present in scoring TMJ pathology on magnetic resonance imaging (MRI). Consensus-driven development and validation of an MRI scoring system for TMJs has important clinical utility in timely improvement of diagnosis and serving as an outcome measure. We report on a multi-institutional collaboration toward developing a TMJ MRI scoring system for JIA. METHODS: Seven readers independently assessed MRI scans from 21 patients (42 TMJs, from patients ages 6-16 years) using 3 existing MRI scoring systems from American, German, and Swiss institutions. Reliability scores, scoring system definitions, and items were discussed among 10 JIA experts through 2 rounds of Delphi surveys, nominal group voting, and subsequent consensus meetings to create a novel TMJ MRI scoring system. RESULTS: Average-measure absolute agreement intraclass correlation coefficients (avICCs) for the total scores of all 3 scoring systems were highly reliable at 0.96 each. Osteochondral items showed higher reliability than inflammatory items. An additive system was deemed preferable for assessing minor joint changes over time. Eight items were considered sufficiently reliable and/or important for integration into the consensus scoring system: bone marrow edema and enhancement (avICC 0.57-0.61, smallest detectable difference [SDD] ± 45-63% prior to redefining), condylar flattening (avICC 0.95-0.96, SDD ± 23-28%), effusions (avICC 0.85-0.88, SDD ± 25-26%), erosions (avICC 0.94, SDD ± 20%), synovial enhancement and thickening (previously combined, avICC 0.90-0.91, SDD ± 33%), and disk abnormalities (avICC 0.90, SDD ± 19%). CONCLUSION: A novel TMJ MRI scoring system was developed by consensus. Further iterative refinements and reliability testing are warranted in upcoming studies.

Temporomandibular Joint Involvement in Association With Quality of Life, Disability, and High Disease Activity in Juvenile Idiopathic Arthritis.

OBJECTIVE: To evaluate the demographic, disease activity, disability, and health-related quality of life (HRQOL) differences between children with juvenile idiopathic arthritis (JIA) and their healthy peers, and between children with JIA with and without clinical temporomandibular joint (TMJ) involvement and its determinants. METHODS: This study is based on a cross-sectional cohort of 3,343 children with JIA and 3,409 healthy peers, enrolled in the Pediatric Rheumatology International Trials Organisation HRQOL study or in the methotrexate trial. Potential determinants of TMJ involvement included demographic, disease activity, disability, and HRQOL measures selected through univariate and multivariable logistic regression. RESULTS: Clinical TMJ involvement was observed in 387 of 3,343 children with JIA (11.6%). Children with TMJ involvement, compared to those without, more often had polyarticular disease course (95% versus 70%), higher Juvenile Arthritis Disease Activity Score (odds ratio [OR] 4.6), more disability, and lower HRQOL. Children with TMJ involvement experienced clearly more disability and lower HRQOL compared to their healthy peers. The multivariable analysis showed that cervical spine involvement (OR 4.6), disease duration >4.4 years (OR 2.8), and having more disability (Childhood Health Assessment Questionnaire Disability Index >0.625) (OR 1.6) were the most important determinants for TMJ involvement. CONCLUSION: Clinical TMJ involvement in JIA is associated with higher disease activity, higher disability, and impaired HRQOL. Our findings indicate the need for dedicated clinical and imaging evaluation of TMJ arthritis, especially in children with cervical spine involvement, polyarticular course, and longer disease duration.

Temporomandibular joint involvement in childhood arthritis: comparison of ultrasonography-assessed capsular width and MRI-assessed synovitis.

OBJECTIVES: Ultrasonography is an effective, low-cost, low-threshold and convenient diagnostic tool in childhood arthritis, but its value in temporomandibular joint (TMJ) involvement is not clear. The purpose of our study was to explore the reliability of ultrasonography to assess TMJ inflammation using contrast-enhanced MRI as reference standard, in order to deduce cut-off values for TMJ capsular width to detect enhanced synovial thickening (synovitis). METHODS: 124 ultrasonography and MRI examinations in 55 patients [mean age 12.4 ± 3.5 years (±standard deviation)], the majority obtained within 1 day, were scored for subcondylar and condylar capsular width (ultrasonography images) and amount of synovitis (MR images). The correlations of these findings were calculated. A receiver operating characteristic (ROC) curve analysis, with MRI findings as reference standard, was obtained. RESULTS: The correlation between ultrasonography-assessed capsular width and MRI-assessed amount of synovitis was moderate both at the subcondylar and condylar level [Spearman's rho (ρ): 0.483; p < 0.001 and 0.347; p < 0.001 respectively]. The ROC curve indicated the best discriminatory ability at the subcondylar level with an area under the curve of 0.77 (95% confidence interval 0.69-0.85) and a cut-off value of 1.2 mm (sensitivity 72%, specificity 70%) for the capsular width. CONCLUSIONS: A moderate correlation between ultrasonography-assessed capsular width and MRI-assessed synovitis was found in childhood arthritis with the best discriminatory ability at the subcondylar level. This indicates that ultrasonography may be a valuable diagnostic tool in the initial assessment of TMJ inflammation.

Disk abnormality coexists with any degree of synovial and osseous abnormality in the temporomandibular joints of children with juvenile idiopathic arthritis.

BACKGROUND: MRI manifestation of temporomandibular joint arthritis is frequently reported in children with juvenile idiopathic arthritis. However, little attention has been paid to temporomandibular joint disk abnormalities. OBJECTIVE: To assess combinations of MRI findings in the symptomatic temporomandibular joint in children with juvenile idiopathic arthritis with focus on disk abnormalities. MATERIALS AND METHODS: This was a retrospective study of 46 patients with juvenile idiopathic arthritis, mean age 12 years (range: 5-17 years). Mean disease duration was 70 months (standard deviation: 61 months). MR images of 92 temporomandibular joints were scored for thickness of abnormally enhancing synovium (synovitis), joint effusion, bone marrow oedema, abnormal bone shape, bone erosion and disk abnormalities. RESULTS: The 92 temporomandibular joints were categorized as A: No synovitis and normal bone shape (30/92; 33%), B: Synovitis and normal bone shape (14/92: 15%), C: Synovitis and abnormal bone shape (38/92; 41%) and D: No synovitis but abnormal bone shape (10/92; 11%). Thirty-six of the 46 patients (78%) had synovitis and 33/46 (72%) had abnormal bone shape, most frequently in combination (30/46; 65%). Disk abnormalities (flat disk, fragmented disk, adherent disk and displaced disk) were found in 29/46 patients (63%). Disk abnormalities were found in all categories of juvenile idiopathic arthritis involved temporomandibular joints (B: 8/14 [57%]; C: 25/38 [66%] and D: 7/10 [70%]). Disk displacement was found in half of the joints (7/14) in category B. Synovitis was most pronounced in this category. CONCLUSION: Disk abnormalities were frequent. Disk displacement also occurred in joints with early temporomandibular joint arthritis, i.e., with normal bone shape. Other disk abnormalities were found in joints with bone abnormalities. Attention should be paid to disk abnormalities both in early and long-standing temporomandibular joint arthritis in children with juvenile idiopathic arthritis.

Temporomandibular joint findings in adults with long-standing juvenile idiopathic arthritis: CT and MR imaging assessment.

PURPOSE: To assess the long-term temporomandibular joint (TMJ) manifestations of juvenile idiopathic arthritis (JIA), as depicted at computed tomography (CT) and magnetic resonance (MR) imaging, in 47 adult patients. MATERIALS AND METHODS: The study was approved by a regional committee for medical research ethics, and informed consent was obtained from all patients. Forty-seven patients with JIA (32 women, 15 men; mean age, 35 years) were examined, on average, 30 years after the initial diagnosis. The findings of TMJ imaging, including CT and MR imaging, were evaluated by three observers. Bone and disk abnormalities, joint effusion, bone marrow abnormalities, and contrast enhancement were analyzed. RESULTS: The TMJs were involved in 33 (70%) of the 47 patients with JIA, with bilateral involvement in 29 patients. Slight to moderate contrast enhancement was observed on the images obtained in 14 (42%) of the 33 patients with TMJ JIA abnormalities. All main joint components were abnormal in 28 of the 33 patients, mainly showing flat deformed condyles, wide flat fossae, and thin or perforated disks in the normal position, or absent disks. Condylar concavity or bifidity, and secondary osteoarthritis were found in approximately half of the abnormal joints. CONCLUSION: Long-term JIA manifestations in the TMJs, as demonstrated at CT and MR imaging, were frequent, usually bilateral, and characterized by mandibular condyle and temporal bone deformities, abnormal disk morphology, and, rather frequently, osteoarthritis and mild synovitis.

Radiographic TMJ abnormalities in patients with juvenile idiopathic arthritis followed for 27 years.

OBJECTIVE: The objective of this study was to assess temporomandibular joint (TMJ) abnormalities in juvenile idiopathic arthritis (JIA) by longitudinal radiographic examinations from childhood to adulthood. STUDY DESIGN: Radiographic TMJ evaluations of 60 JIA patients were obtained at baseline (mean age 8.6 years, mean disease duration 3.2 years) and 1 to 3 times thereafter, with the final examination on average 27 years after baseline. A radiographic grading system for severity of TMJ abnormality was applied. RESULTS: Cumulative radiographic TMJ abnormalities increased from baseline to final examination (42% to 75%, P < .001), as did bilateral TMJ involvement (60% to 82%, P < .001). Of patients with TMJ abnormalities, 53% showed progression, and 16% revealed signs of improvement. TMJ abnormalities were associated with physical limitations at baseline and reduced well-being and more extensive joint involvement at the final examination. CONCLUSION: The frequency of TMJ abnormalities in JIA was high and increased from childhood to adulthood. Although progression of TMJ abnormalities was the general rule, near normalization also occurred on occasion.

Average craniofacial development from 6 to 35 years of age in a mixed group of patients with juvenile idiopathic arthritis.

OBJECTIVE: To investigate long term the average changes in craniofacial morphology in a group of Norwegian juvenile idiopathic arthritis (JIA) patients with mixed diagnosis from 6 to 35 years of age. A matched group of healthy individuals was included as controls. MATERIAL AND METHODS: Craniofacial development in 38 females and 16 males with JIA was followed on lateral cephalograms from childhood for 23-31 years. The patients were compared with the healthy individuals at the ages of 6, 9, 12, and 35 years. RESULTS: At 6 and 9 years of age, the average craniofacial morphology in the JIA patients was similar to that of the control subjects. At 12 years of age, significant craniofacial morphological differences between the JIA and the control subjects appeared. These included a steeper mandibular plane angle and a more retrognathic position of the mandible. The length of the mandible (ar-gn), the height of the ramus (ar-tgo), and the length of the corpus (tgo-gn) were significantly smaller in the JIA patients. The average growth direction of the chin was more downward in the JIA patients. A smaller posterior facial height and a higher ratio between the anterior and posterior facial heights were also observed. The differences in craniofacial morphology between the patients and the control group were more pronounced at 35 years of age than at earlier ages. CONCLUSION: The typical craniofacial morphological pattern in JIA patients was established between 9 and 12 years of age. From the age of 12 until the age of 35, this morphological pattern remained relatively stable, in contrast to the pattern in the healthy control subjects.

Role of magnetic resonance imaging in the clinical diagnosis of the temporomandibular joint.

Temporomandibular joint (TMJ) abnormalities cannot be reliably assessed by a clinical examination. Magnetic resonance imaging (MRI) may depict joint abnormalities not seen with any other imaging method and thus is the best method to make a diagnostic assessment of the TMJ status. In patients with temporomandibular joint disorder (TMD) referred for diagnostic imaging the predominant TMJ finding is internal derangement related to disc displacement. This finding is significantly more frequent than in asymptomatic volunteers, and occurs in up to 80% of patients consecutively referred for TMJ imaging. Moreover, certain types of disc displacement seem to occur almost exclusively in TMD patients, namely complete disc displacements that do not reduce on mouth opening. Other intra-articular abnormalities may additionally be associated with the disc displacement, predominantly joint effusion (which means more fluid than seen in any asymptomatic volunteer) and mandibular condyle marrow abnormalities (which are not seen in volunteers). These conditions seem to be closely related. Nearly 15% of TMD patients consecutively referred for TMJ MRI will have joint effusion, of whom about 30% will show bone marrow abnormalities. In a surgically selected material of joints with histologically documented bone marrow abnormalities nearly 40% showed joint effusion. Disc displacement is mostly bilateral, but joint effusion seems to be unilateral or with a lesser amount of fluid in the contralateral joint. Abnormal bone marrow is also mostly unilateral. Many patients have unilateral pain or more pain on one side. In a regression analysis the self-reported in-patient TMJ pain side difference was positively dependent on TMJ effusion and condyle marrow abnormalities, but negatively dependent on cortical bone abnormalities. Of the joints with effusion only one fourth showed osteoarthritis. Thus, there seems to be a subgroup of TMD patients showing more severe intra-articular pathology than disc displacement alone, and mostly without osteoarthritis. It should, however, be emphasized that patients with TMJ effusion and/or abnormal bone marrow in the mandibular condyle seem to constitute only a minor portion (less than one fourth) of consecutive TMD patients referred for diagnostic TMJ imaging. The majority of patients have internal derangement related to disc displacement, but without accompanying joint abnormalities. In patients with rheumatoid arthritis and other arthritides TMJ involvement may mimick the more common TMDs. Using MRI it is possible, in most cases, to distinguish these patients from those without synovial proliferation.

Cephalometric analysis with digital storage phosphor images: extreme low-exposure images with and without postprocessing noise reduction.

This study evaluated extreme exposure reduction in cephalography with monitor-displayed DICOM (Digital Imaging and Communication in Medicine, Rosslyn, Va) images. The purposes were to investigate to what extent exposure can be reduced without losing diagnostic information for tracing analysis, whether postprocessing noise reduction could benefit localization of anatomic landmarks in extreme low-exposure images, and the quality of the images. Three images (optimal, extreme low exposure, and noise-reduced extreme low exposure) were obtained from 24 volunteers. Three orthodontists traced 18 landmarks and subjectively judged the quality of the images. Sixteen of the landmarks were well identified on the extreme low-exposure images when they were compared with the optimal images. Apex inferius and apex superius were not well identified. The evaluation of image quality on a visual analogue scale showed that the optimal images were given the highest scores, extreme low-exposure images with postprocessing noise reduction the second highest scores, and extreme low-exposure images the lowest scores. Monitor-based tracing analysis on storage phosphor cephalographic images with a 94% exposure reduction, compared with conventional exposure, can be performed with only 2 of 18 landmarks not well identified. The landmarks were better identified on the low-exposure images with standard postprocessing than on the images with post-processing noise reduction, although the subjective evaluation of the image quality indicated the opposite.