Improving treatment of the temporomandibular joint in juvenile idiopathic arthritis: let’s face it

KEYWORDS:

• Juvenile idiopathic arthritis
• juvenile chronic arthritis
• juvenile rheumatoid arthritis
• arthritis
• temporomandibular joint
• facial morphology
• orofacial examination
• clinical examination
• treatment

1. Introduction

Temporomandibular joint (TMJ) arthritis is a frequent feature of Juvenile Idiopathic Arthritis (JIA) and affects up to 8 out of 10 children with JIA, irrespective of their JIA subtype [1–3]. For decades the TMJ has been an underrecognized joint in juvenile arthritis. However, in the last 2 decades research in JIA associated TMJ arthritis has increased significantly and most recently the TMJ juvenile arthritis working (TMJaw) group (formerly known as euroTMjoint) has published some landmark papers in this area and according to the authors have increased the awareness of the importance of the TMJ in JIA [4–6]. The terminology around JIA associated TMJ arthritis has been confusing and has led to the inability to compare studies due to the inclusion of different stages of JIA associated TMJ arthritis. A recent international TMJaw group consensus paper has addressed this problem and has suggested an international terminology specifying between TMJ arthritis (active TMJ arthritis diagnosed by gadolinium enhanced MRI) and TMJ involvement (abnormalities presumed to be the result of TMJ arthritis) [5].

JIA associated TMJ involvement can lead to abnormal dentofacial development (TMJ deformity) and significant facial disabilities, including orofacial pain, reduced TMJ mobility and masticatory function, and esthetical consequences due to facial asymmetry or micrognathia [2,7]. Orofacial manifestations of JIA can impact the oral health related quality of life and significantly impact the day to day living of children with JIA [8,9].

One or both TMJs can be involved in JIA, early or late in the disease process and sometimes can be the first and only joint involved [3,10]. The TMJ is specifically vulnerable to arthritis-induced growth impairment due to the superficial position of the growth plate in the mandibular condyle. Continuous inflammation can lead to cortical damage and erosions alike all other joints; however, in the TMJ the growth plate can be damaged potentially leading to uni- or bilateral dentofacial deformity.

2. Monitoring the temporomandibular joint

Early TMJ arthritis can develop insidiously and silently [11,12]. TMJ involvement with damage to the joints due to previous arthritis but no current active arthritis can be associated with signs and symptoms with functional limitations. Although signs and symptoms are an important part of the TMJ evaluation, the sensitivity and specificity of TMJ arthritis diagnosis are low, and in many children, there is no correlation between signs and symptoms and the presence of active TMJ arthritis on MRI [9,12].

The clinical examination is an important part of the day to day evaluation of JIA patients and should include the TMJs in a standardized fashion [4]. The clinical orofacial examination constitutes an essential component of the clinical assessment of individuals with JIA, and serves four equally important purposes: (1) the detection of clinical signs of active TMJ arthritis that should prompt further clinical and imaging investigations; (2) the detection of orofacial manifestations caused by previous TMJ arthritis (TMJ involvement); (3) the assessment of craniofacial growth and development in skeletally immature subjects; and (4) the assessment of the longitudinal progression of orofacial symptoms and dysfunction in patients who have already been diagnosed with active TMJ arthritis or TMJ involvement [4].

Diagnosing JIA associated TMJ arthritis remains difficult as imaging is necessary, and signs and symptoms are unreliable to help differentiate between active and inactive TMJ arthritis. Currently, the diagnosis of active JIA associated TMJ arthritis mandates gadolinium-enhanced magnetic resonance imaging (MRI) [11,13]. Other forms of imaging, such as ultrasonography and computer tomography (CT) are not reliable to diagnose active TMJ arthritis. For a more in-depth evaluation of the bony structures Cone beam CT (CBCT) is a better modality than the MRI and can be used for functional evaluation and surgery planning [14]. Ideally, all newly diagnosed JIA patients should receive an MRI to assess the TMJs at diagnosis. However, in real life access to MRI examinations can be limited which underlines the important for routine orofacial assessment of a multidisciplinary team. During the disease course, TMJ arthritis can develop at any time and is often asymptomatic until growth disturbances or functional impairment is present and physicians should have a low threshold to repeat the MRI. There are currently no evidence based guidelines how often to repeat an MRI in children with JIA.

3. Management of temporomandibular joint involvement

Like other joints in JIA, there is no one-size-fits-all treatment strategy for TMJ arthritis. Treatment of JIA associated TMJ arthritis should be anchored in a tailored interdisciplinary approach with individual plans for all patients. Management of TMJ involvement and the associated facial conditions in the JIA patient include systemic and local administrated drug therapy, orthopedic devices (oral splints), facial physiotherapy, and surgical intervention. Active TMJ arthritis warrants treatment with immunosuppressive medications often prescribed in JIA and can consist of disease modifying medication such as methotrexate and/or biological therapy [15]. Some providers advocate that active TMJ arthritis should be treated aggressively with biologics, alike sacroillitis, as many children develop refractory TMJ inflammation. However, often care-providers are limited due to insurance constraints in prescribing these medications as first-line agents in JIA. Local treatment options predominantly used to consist of intra-articular corticosteroid injections (IACI). Although IACI has been shown to reduce pain and increase mouth opening capacity, the effect on long-term inflammation remains uncertain and recent publications have shown this treatment can lead to heterotopic bone formation and reduced mandibular growth and should be avoided in growing patients [16,17]. Intra-articular lavage (without corticosteroid deposition) is another local treatment option that has shown to be effective to reduce pain and increase mouth opening capacity and might be an alternative treatment option in the growing patients.

Intra-articular infliximab injections have been studied in a severe subset of JIA patients and were not shown to be effective in this group of refractory patients [18].

Orthodontic treatment with orthopedic devices can be used either in parallel with systemic or local therapy in children with active TMJ arthritis or can be used as single treatment of arthritis induced dentofacial deformity and symptoms. Unilateral TMJ involvement in JIA often leads to asymmetric dentofacial growth. Orthopedic functional appliance treatment such as the distraction splint can lead to reduced mandibular asymmetry and normalize the mandibular vertical growth in the affected side [19]. Another study has shown the positive effect of oral stabilization splint application on orofacial pain frequency and intensity and significant improvement of TMJ function [20]. The use of oral splints for JIA associated TMJ arthritis and its sequalae is very dependent on the healthcare system the patient depends on. In countries where orthopedic devices are covered by health care insurance or government programs the uptake and implementation of these devices is much higher with promising results. However, these treatments can be expensive for the individual patient if not covered and when pricing is not governed. The development and use of these orthopedic devices is not part of most dental/orthodontic official training programs and extra training might be necessary, limiting this option for some patient populations.

Functional impairment and dentofacial deformity due to condylar erosion and destruction or the arthritis-induced inhibitory effect on mandibular growth may lead to the need for surgical intervention. Resnick et al. [6] describe an algorithm for management of facial growth disturbances resulting from JIA. The algorithm was developed by the TMJaw surgical task force during a multinational consensus conference involving surgeons and orthodontists with special expertise in this area. According to the algorithm, treatment options are based on the skeletal maturity and the degree of asymmetry and or loss of vertical height. Surgical interventions consist of orthognatic surgery including distraction osteogenesis or autologous or alloplastic joint replacement. The success of the implementation of distraction osteogenesis in growing patients with TMJ involvement and dentofacial asymmetry has been studied [6]. Most studies on autologous or alloplastic joint replacements are case reports or very small case series. The algorithm by Resnick et al. does not only include surgical interventions but also the need to optimize the systemic and or orthopedic treatments demonstrating the multidisciplinary approach of JIA associated TMJ arthritis with the help of five cases [6].

Timely diagnosis of TMJ arthritis and the associated facial conditions is the first step for the initiation of proper management. Orofacial examination therefore constitutes an essential part of the routine assessment in JIA. Management of TMJ arthritis or involvement in children with JIA warrants a multidisciplinary approach. The optimal team for management of TMJ involvement involves the rheumatologist, orthodontist, dental facial specialist, maxillofacial surgeon, radiologists, physiotherapist, and other associated care providers. Diagnosing JIA associated TMJ arthritis is based on radiology with the MRI with gadolinium enhancement being the gold-standard in current practice. It is important for the rheumatologist, orthodontist, physiotherapist, and other care providers to work together to provide the tailored treatment for the JIA patient with TMJ arthritis (active inflammation) or TMJ involvement due to sequalae of previous TMJ arthritis. The multidisciplinary nature of the treatment demands standardized terminology and orofacial clinical evaluations to enhance good communication between all care providers to increase the oral related quality of life of the JIA patient and prevent long-term facial disabilities and damage.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

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Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

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Funding

This paper was not funded.