Orthodontics for treating temporomandibular joint (TMJ) disorders

Temporomandibular disorders (TMD) relate to discomfort of the temporomandibular joint (TMJ). The disorder is multifactorial with a degree of psychogenic influence varying throughout an individual's life with phases of symptoms affecting the quality of life. In an attempt to treat this complex group of disorders many treatment modalities have been identified some of which are also considered in other Cochrane reviews. The disorder also has a normal cycle of events appearing to spontaneously improve without treatment.

To establish the effectiveness of orthodontic intervention in reducing symptoms in patients with TMD (compared with any control group receiving no treatment, placebo treatment or reassurance) and to establish if active orthodontic intervention leads to TMD.

The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched. Handsearching of orthodontic journals and other related journals was undertaken in keeping with the Cochrane Collaboration handsearching programme. No language restrictions were applied. Authors of any studies were identified, as were experts offering legal advice, and contacted to identify unpublished trials. Most recent search: 13th April 2010.

All randomised controlled trials (RCTs) including quasi-randomised trials assessing orthodontic treatment for TMD were included. Studies with adults aged equal to or above 18 years old with clinically diagnosed TMD were included. There were no age restrictions for prevention trials provided the follow-up period extended into adulthood. The inclusion criteria required reports to state their diagnostic criteria for TMD at the start of treatment and for participants to exhibit two or more of the signs and/or symptoms. The treatment group included treatment with appliances that could induce stable orthodontic tooth movement. Patients receiving splints for 8 to 12 weeks and studies involving surgical intervention (direct exploration/surgery of the joint and/or orthognathic surgery to correct an abnormality of the underlying skeletal pattern) were excluded. The outcomes were: how well were the symptoms reduced, adverse effects on oral health and quality of life.

Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in triplicate and independently by three review authors. As no two studies compared the same treatment strategies (interventions) it was not possible to combine the results of any studies.

The searches identified 284 records from all databases. Initial screening of the abstracts and titles by all review authors identified 55 articles which related to orthodontic treatment and TMD. The full articles were then retrieved and of these articles only four demonstrated any data that might be of value with respect to TMD and orthodontics. After further analysis of the full texts of the four studies identified, none of the retrieved studies met the inclusion criteria and all were excluded from this review.

There are insufficient research data on which to base our clinical practice on the relationship of active orthodontic intervention and TMD. There is an urgent need for high quality randomised controlled trials in this area of orthodontic practice.When considering consent for patients it is essential to reflect the seemingly random development/alleviation of TMD signs and symptoms.