Clinical update: Temporomandibular disorder

Temporomandibular disorder (TMD) is a term used for a group of musculoskeletal (MSK) conditions that involve the temporomandibular joints (TMJ) and the masticatory muscles. Up to 30 per cent of adults will experience TMD. From 3.6-7 per cent of the population will seek treatment for TMD (American Academy of Orofacial Pain 2013).

 

Common TMD signs and symptoms include: pain affecting the masticatory muscles and TMJ; an increase in pain with jaw activity such as chewing; limited mouth-opening; and TMJ sounds such as clicking. Patients with TMD often have other coexisting pain conditions. The cause of TMD is multifactorial. Factors commonly associated with TMD include: facial trauma, daytime oral habits, nocturnal bruxism, poor posture and emotional stress. Patients will present with an individual profile of contributing factors. 

Management should be based on the use of conservative, reversible and evidence-based interventions including education, physical therapy, intraoral occlusal appliances, pharmacological therapy and psychological support. These interventions do not produce irreversible changes, therefore presenting much less risk of harm.  Early diagnosis and intervention helps prevent development of chronic symptoms (American Academy of Orofacial Pain 2013).

 

Even where patients have longstanding and severe TMD symptoms, they do not usually require invasive treatment. Failure of conservative interventions does not indicate a need to progress to irreversible treatment such as occlusal adjustments or surgery (Royal College of Surgeons 2015). 

 

TMD is a dental specialism. Secondary care physiotherapy services typically receive referrals from dental and maxillofacial specialists.  Patients referred to physiotherapy via non-dental health professionals should be advised to see their general dental practitioner for intraoral screening and to consider treatment such as occlusal appliance therapy. 

Systematic reviews provide evidence that modalities used by physiotherapists can be effective for TMD. However, a lack of high-quality research means the evidence is not definitive. Further standardised evaluations and better study designs are needed (Calixtre et al 2015, Paço et al 2016). Since undergraduate physiotherapy courses do not include TMD teaching, specialist training is required. 

A classification system for TMD based on frequent signs and symptoms can be used to guide management. There are three main groups of common TMD: masticatory muscle disorders, TMJ disorders, and headache attributed to TMD (Schiffman et al 2014).

 

The clinical history should lead to a provisional classification; examination of the masticatory system then helps to confirm or refute this. A reliable TMD assessment protocol exists (www.rdc-tmdinternational.org). Biomechanical and neurophysiological interactions between the jaw, head and neck mean TMD and cervical spine disorders have similar signs and symptoms. As a result, the neck should also be examined (de Wijer and Steenks 2010).

 

Other conditions present with orofacial pain; clinicians must consider other causes (International Headache Society 2013). Familiarisation with craniofacial ‘red flag’ signs and symptoms is necessary. For more information, visit the clinical knowledge summaries section on the National Institute for Health and Care Excellence website (cks.nice.org.uk).Prompt specialist referral is warranted if serious pathology is suspected.

 

Psychometric instruments should be used to screen for dominant psychological disorders (such as depression and anxiety). If a dominant psychological disorder is suspected, specialist referral is warranted, otherwise attempts to manage pain and dysfunction are likely to fail.  

 

As with other MSK conditions, persistent TMD will be associated with a combination of interacting (modifiable and non-modifiable) biopsychosocial factors. Long-term success requires a thorough and accurate assessment to identify the main contributing factors, with tailored interventions to target the modifiable factors and minimise loading on the masticatory system. 

For persistent TMD-related pain, psychosocial factors are associated more strongly with pain intensity, disability and prognosis than biomedical findings. Substantial improvements are unlikely with biomedical treatment alone (Turner and Dworkin 2004). Physiotherapy combines biophysical and psychological interventions to reduce pain, improve jaw function and facilitate self-management.

 

Patient education is crucial to address psychological impairment.  Understanding the disorder and how contributing factors can overload the masticatory system to create a persistent cycle of pain helps the patient make sense of their disorder. This, in turn, reduces the threat of symptoms. Explanation facilitates acceptance of the disorder and establishes a rationale for specific treatment, helping with compliance.  Information leaflets, anatomical images and models can reinforce understanding.

 

A management plan should be developed together with the patient to enable them to minimise their contributing factors; patients must understand their central role in managing their disorder. The patient’s TMD classification and physical impairments will guide manual therapy techniques and the home-care programme. The emphasis should be on self-management.

 

Manual therapy can reduce muscle tension and guarding, and help restore TMJ mobility. Intra- and extra-oral massage, stretching and TMJ mobilisation techniques are commonly used (Tuncer et al 2013).  As an adjunct, acupuncture or dry needling can help reduce pain and promote muscle relaxation (AAOP 2013).

 

An individualised home-care programme can include: strategies to reduce daytime oral habits and improve jaw and spine posture; jaw relaxation techniques; sleep hygiene and other advice to reduce loading on the TMJ and muscles; self-massage techniques; and proprioceptive, stretching or self-mobilising exercises (Michelotti et al 2005)

 

Specialist referral is warranted if signs and symptoms do not improve or become more severe. Further investigation and additional treatment such as occlusal appliances, pharmacological therapy and specialist psychological support can be considered. fl

 

Association of Chartered Physiotherapists in Temporomandibular Disorders