Burning mouth syndrome (BMS) is a common painful condition. Symptoms include burning, dryness or uncomfortable sensations in the mouth and changes to taste. There is no obvious underlying medical or dental cause, however scientific research suggests that BMS may be caused by underlying damage to the nerves. BMS is often a persistent and long term condition, which can lead to a reduced quality of life (QoL). There are many treatments available including drugs for treating psychological conditions and increasing saliva production, protective barriers, and treatments applied to the mouth surface.
What was the research?
A systematic review to find out which treatments help to relieve symptoms for people with burning mouth syndrome.
Who conducted the research?
The research was conducted by a team led by Roddy McMillan from Eastman Dental Hospital, London, on behalf of Cochrane Oral Health. Heli Forssell, John A.G. Buchanan, Anne-Marie Glenny, Jo C. Weldon and Joanna M. Zakrzewska were also on the team.
What evidence was included in the review?
We found 23 randomized controlled trials to include in this review. 1,121 people took part in the trials, 83% of whom were women. The trials were published between 1995 and 2015. Twenty-one trials assessed short-term (up to three months) symptom relief, and four studies assessed long-term (from three to six months) symptom relief. Seventeen studies provided information about side effect occurrence, seven studies assessed a measure of QoL, and two studies assessed changes in taste and feeling of dryness.
23 treatments were included in this review: including antidepressants and antipsychotics, antiseizure drugs, types of tranquillisers, saliva stimulants, dietary supplements, directed energy waves, physical barriers, psychological therapies, and treatments applied to the mouth surface. In the clinical trials, they were compared to placebo.
What did the evidence say?
We found evidence of short-term symptom relief for directed energy waves, topical clonazepam (a type of tranquiliser held in the mouth before being removed), thin plastic tongue covers, and the anti-seizure drug gabapentin. There was no difference in short-term symptom relief found for antidepressants, saliva stimulants, and clonazepam taken systemically (swallowed). We were unable to show whether dietary supplements or treatments applied to the mouth surface provide symptom relief in the short term or not.
We found evidence of long-term symptom relief for psychological therapy, chili pepper mouthrinse and topical clonazepam. We found there was no difference in long-term symptom relief for dietary supplements or treatments applied to the mouth surface. Studies which assessed antidepressants, directed energy waves, saliva stimulants, antiseizure drugs, or physical barriers did not evaluate long-term symptom relief.
A few studies assessed short-term change in taste or feeling of dryness, but there was not enough evidence to judge the effects of treatment on these outcomes.
Side effects were more likely to be experienced with antidepressants, and with a dietary supplement called alpha lipoic acid. Side effects experienced with antidepressants included dizziness and drowsiness. Headaches and upset stomachs were associated with alpha lipoic acid.
How good was the evidence?
Overall, we found very low-quality evidence in all the treatments we assessed for the relief of symptoms, changes in QoL, taste and feeling of dryness. As we found so few studies at low risk of bias, we are currently unable to prove or disprove the effectiveness of any treatments for managing BMS.
What are the implications for dentists and the general public?
There is not enough high-quality research evidence to produce clear guidance for treating BMS patients. Clinicians should discuss treatment options with patients.
What should researchers look at in the future?
Further randomised controlled trials of longer duration (a minimum of three months follow-up) and high methodological quality are needed to establish which of the available treatments are effective for patients suffering from BMS. Trials should be reported according to CONSORT guidance.
McMillan R, Forssell H, Buchanan JAG, Glenny AM, Weldon JC, Zakrzewska JM. Interventions for treating burning mouth syndrome. Cochrane Database of Systematic Reviews 2016, Issue 11. Art. No.: CD002779. DOI: 10.1002/14651858.CD002779.pub3.