Prevalence of temporomandibular disorder in children and adolescents with juvenile idiopathic arthritis - a Norwegian cross- sectional multicentre study.

BACKGROUND: Children and adolescents with juvenile idiopathic arthritis (JIA) may suffer pain from temporomandibular disorder (TMD). Still, routines for the assessment of temporomandibular joint (TMJ) pain in health and dental care are lacking. The aims of this study were to examine the prevalence of TMD in children and adolescents with JIA compared to their healthy peers and to investigate potential associations between JIA and TMD. METHODS: This comparative cross-sectional study is part of a longitudinal multicentre study performed during 2015-2020, including 228 children and adolescents aged 4-16 years with a diagnosis of JIA according to the ILAR criteria. This particular substudy draws on a subset of data from the first study visit, including assessments of TMD as part of a broader oral health examination. Children and adolescents with JIA were matched with healthy controls according to gender, age, and centre site. Five calibrated examiners performed the clinical oral examinations according to a standardised protocol, including shortened versions of the diagnostic criteria for TMD (DC/TMD) and the TMJaw Recommendations for Clinical TMJ Assessment in Patients Diagnosed with JIA. Symptoms were recorded and followed by a clinical examination assessing the masticatory muscles and TMJs. RESULTS: In our cohort of 221 participants with JIA and 221 healthy controls, 88 (39.8%) participants with JIA and 25 (11.3%) healthy controls presented with TMD based on symptoms and clinical signs. Painful TMD during the last 30 days was reported in 59 (26.7%) participants with JIA vs. 10 (5.0%) of the healthy controls (p <  0.001). Vertical unassisted jaw movement was lower in participants with JIA than in controls, with means of 46.2 mm vs. 49.0 mm, respectively (p <  0.001). Among participants with JIA, a higher proportion of those using synthetic disease-modifying antirheumatic-drugs and biologic disease-modifying antirheumatic-drugs presented with painful masticatory muscles and TMJs at palpation. CONCLUSION: Symptoms and clinical signs of TMD were seen in approximately half of the JIA patients compared to about one fourth of their healthy peers. Painful palpation to masticatory muscles and decreased vertical unassisted jaw movement were more frequent in participants with JIA than among healthy controls and should be part of both medical and dental routine examinations in patients with JIA.

Normative values for mandibular mobility in Scandinavian individuals 4-17 years of age.

Assessment of mandibular mobility is an important part of the clinical oro-facial examination of paediatric and adolescent patients. The aims of the present cross-sectional study were to establish age-related normative values for mandibular mobility in a Scandinavian paediatric and adolescent cohort and to assess the validity of universal cut-off values for lower 'normal' mandibular ranges of motion. A total of 1114 Danish individuals between 4-17 years of age were included. Maximal mouth opening capacity and laterotrusion capacity were assessed, in each individual, according to a standardised measurement protocol. The mean maximal mouth opening capacity gradually increased from 38 mm (SD 6·1 mm) at age 4 to 54·5 mm (SD 6·8 mm) at age 17. No inter-gender difference in maximal mouth opening capacity was observed (P > 0·15). The mean maximal laterotrusion capacity gradually increased from 7·4 mm (SD. 1·1 mm) at age four to 10·1 mm (SD 1·9 mm) at age 17. A statistical significant inter-gender difference of 0·8 mm (SD 0·4 mm) was observed in relation to the total laterotrusion capacity; however, the clinical relevance of this significant difference is questionable. Normative values of mandibular function was established in individuals 4-17 years of age. Our findings oppose the use of a single universal cut-off value for 'normal' range of motion in paediatric and adolescent patients. Instead, we recommend to use the age-related normative values of mandibular range of motion as basis for the assessment of the development of oro-facial function.

Management of temporomandibular joint arthritis-related orofacial symptoms in juvenile idiopathic arthritis by the use of a stabilization splint.

OBJECTIVES: Temporomandibular joint (TMJ) inflammation in patients with juvenile idiopathic arthritis (JIA) may interfere with optimal joint and muscle function. Orofacial symptoms are common findings in relation to TMJ arthritis. Previous research on management of TMJ arthritis-related orofacial symptoms in patients with JIA has focused on pharmacological treatment modalities without involving physical pain management strategies. The aim of this study was to evaluate changes in orofacial pain and TMJ function after stabilization splint treatment. METHOD: Twenty-eight consecutive patients with JIA and arthritis-related orofacial symptoms (mean age 15.5 years, range 8.2-25 years) were included in this prospective observational study. All patients received stabilization splint treatment. A comparable group of 110 healthy children served as controls for the assessments of TMJ mobility. RESULTS: After splint treatment for 8 weeks, a significant reduction in orofacial pain frequency and intensity was reported, and significant improvement in TMJ function was observed. However, TMJ mobility at follow-up remained significantly reduced when compared to the control group. CONCLUSIONS: The stabilization splint is a safe, reversible, low-cost treatment, and familiar to most dental practitioners. Based on our findings, we propose the implementation of stabilization splint therapy for the treatment of JIA patients with TMJ arthritis-related symptoms.

Cytokines in healthy temporomandibular joint synovial fluid.

Analysis of temporomandibular joint (TMJ) synovial fluid may elucidate the aetiology of temporomandibular disorders and arthritic conditions, as well as the inflammatory mechanisms involved. Knowledge about healthy synovial fluid is necessary to understand TMJ pathologies. We aimed to quantify the proinflammatory cytokines interleukin (IL)-1ß, IL-2, IL-6 and tumour necrosis factor (TNF), and the anti-inflammatory cytokines IL-10 and interferon (IFN)-γ in healthy TMJ synovial fluid to serve as reference values for future studies on TMJ pathologies. Twenty healthy, young adult volunteers without temporomandibular dysfunction were included. Bilateral synovial fluid samples were obtained using the push-pull technique with hydroxocobalamin described by Alstergren in 1999. Cytokines were quantified with Luminex multiplex assays and compared using nonparametric statistical analysis. No serious adverse effects were reported. Of 40 possible samples, 14 fulfilled the strict sampling criteria and were included in the analysis. Cytokine values (reported as medians with interquartile ranges) were as follows: TNF, 23 (13-37) pg mL(-1) ; IL-2, 1·8 (0-22) pg mL(-1) ; and INF-γ, 10 (0-47) pg mL(-1) . IL-1ß, IL-6 and IL-10 were almost undetectable. In addition, TNF and INF-γ cytokine levels correlated. We demonstrated that TNF was consistently detected and IFN-γ and IL-2 sporadically detected in the TMJ synovial fluid of healthy individuals using the hydroxocobalamin method and a multiplex assay. The cytokines IL-10, IL-1ß and IL-6 were barely detectable in this sample of healthy TMJs.

Smallest detectable differences in clinical functional temporomandibular joint examination variables in juvenile idiopathic arthritis.

OBJECTIVE: Temporomandibular joint (TMJ) arthritis in juvenile patients may interfere with optimal joint function and mouth opening patterns. Clinical assessment of maximal mouth opening capacity, laterotrusion and protrusion is critical to TMJ arthritis diagnosis, treatment choice and evaluation of a therapeutic intervention. The aim of the study was to determine the smallest minimal threshold at which differences in maximal mouth opening capacity, laterotrusion, and protrusion between two consecutive observations can be determined. SETTING AND SAMPLE POPULATION: Department of Orthodontics, University of Aarhus, Denmark. Forty-two consecutive patients with juvenile idiopathic arthritis. MATERIAL AND METHODS: Two experienced dentists used a calibrated metallic ruler to measure maximal mouth opening capacity, laterotrusion, and protrusion. Each measurement was carried out thrice by each observer. Intra- and inter-observer variation and the smallest detectable difference were calculated for each variable. RESULTS: The smallest detectable differences were as follows: maximal mouth opening capacity 4.9 mm, laterotrusion 2.4 mm, and protrusion 2.8 mm (one observer and one measurement). These differences declined when measurements were repeated; maximal mouth opening capacity 3.3 mm, laterotrusion 1.4 mm, and protrusion 1.8 mm (two observers with three measurements each). We found no support for a relationship between measurement variation and patient age, measurement variation and TMJ pain, or between measurement variation and previous/current TMJ arthritis. CONCLUSION: The importance of the implementation of a standardized measurement protocol is emphasized including repeated measurements to reduce the smallest detectable difference.

Condylar lesions in relation to mandibular growth in untreated and intra-articular corticosteroid-treated experimental temporomandibular joint arthritis.

OBJECTIVES: To evaluate condylar lesions in relation to mandibular growth in experimental temporomandibular joint (TMJ) arthritis and to assess the outcome of treating this condition with repeated intra-articular corticosteroid injections (IACIs). METHODS: Forty-two 10-week-old rabbits were randomly divided into four groups. Seven animals served as controls. Experimental TMJ arthritis was induced in five animals which received intra-articular TMJ saline injections. Fifteen animals had TMJ arthritis induced and were left untreated and 15 animals had TMJ arthritis induced and were treated with IACIs one week after each TMJ antigen-challenge procedure. Inter-group growth differences were evaluated from head computerised tomography scans taken at the time of arthritis induction and 12 weeks later. The variables assessed were: progression of condylar lesions (erosions/flattening/osteophytes), mandibular bone volume changes, condylar and sagittal ramus growth. RESULTS: No inter-group differences in the progression of condylar lesions were observed despite reduced mandibular growth in all three experimental groups. The most pronounced unfavourable mandibular growth alterations were observed in the corticosteroid-treated arthritis animals. CONCLUSIONS: No evidence was found in support of a relation between reduced mandibular growth and condylar lesions. We propose that: 1) condylar lesions are not the only causative factor of reduced mandibular growth in experimental TMJ arthritis, and 2) repeated IACIs have a very unfavourable impact on mandibular growth in experimental TMJ arthritis - treatment is more detrimental to mandibular growth than the TMJ arthritis itself.

Surgical correction of dentofacial deformities in juvenile idiopathic arthritis: a systematic literature review.

The aim of this study was to assess current evidence for the surgical correction of dentofacial deformities in patients with temporomandibular joint (TMJ) involvement from juvenile idiopathic arthritis (JIA). A systematic literature review, according to the PRISMA guidelines, was conducted. Meta-analyses, randomized controlled trials, cohort studies, observational studies, and case reports were eligible for inclusion. Exclusion criteria were no JIA diagnosis, no clearly defined outcomes, dual publications (except meta-analyses), non peer-reviewed studies, non English language publications, and animal studies. The outcome measures assessed were TMJ function, skeletal alignment, and morbidity. The database search identified 255 citations, of which 28 met the eligibility criteria. Of these, 24 were case reports or case series with a low level of evidence that did not allow for meta-analysis. Extrapolated evidence supports orthognathic surgery in skeletally mature patients with controlled or quiescent JIA and a stable dentofacial deformity. Distraction osteogenesis was recommended for severe deformities. Some authors demonstrated unpredictable postoperative mandibular growth with costochondral grafts. Alloplastic TMJ reconstruction was efficacious, but should be used cautiously in skeletally immature patients. TMJ function and skeletal alignment was improved with reconstruction by any technique and morbidity was low. The surgical correction of arthritis-induced dentofacial deformities is indicated but the level of evidence is low. Prospective multicenter studies are needed.