Is hypnosis or relaxation therapy effective for temporomandibular disorders (TMD)?
Date of publication of the systematic review: 2015)
Design
Systematic review of 3 randomized controlled trials (RCTs).
Participants
159 patients with TMD or an equivalent condition with any of the following characteristics: (a) myofascial pain, (b) internal derangement of the joint, or (c) degenerative joint disease (mean age: not reported, male %: 18.1%).
Intervention
Hypnosis exercise or relaxation therapy with three components (hypnotic induction, deep relaxation, specific instruction on pain reduction) was provided as intervention. The reviewers did not report frequency or duration of the intervention.
Comparator
Comparison: Hypnosis or relaxation therapy versus no or minimal treatment.
Major Outcomes
Outcome 1: Post-intervention intensity of TMD-related pain as assessed by 100-mm visual analog scale (VAS);
Outcome 2: Post-intervention maximal pain as assessed by VAS;
Outcome 3: Post-intervention active (voluntary) maximal mouth opening.
Settings
The included trials were performed in an outpatient setting.
Comparison    Hypnosis or relaxation therapy versus no or minimal treatment
Main Results
Compared to no or minimal treatment, hypnosis or relaxation therapy did not show a significant pain reduction for TMD patients (pooled mean difference (pooled MD): -9.16, 95% CI: -23.47 to 5.14). However, hypnosis or relaxation therapy significantly reduced maximal pain (MD: -28.33, 95% CI: -44.67 to -11.99) and improved active (voluntary) maximal mouth opening (MD: -2.63, 95% CI: -3.30 to -1.96).
Comparison: Hypnosis or relaxation therapy versus no or minimal treatment in TMD patients
Outcomes (units) No. of studies (Total number of participants) Mean value/No. of participants Heterogeneity test ( I2) Pooled MD/MD (95% CI) p value Overall quality of evidence*
Intervention Comparator
1 (mm) 3 (144) Not reported /75 Not reported/69 76% -9.16(-23.47 to 5.14) 0.21 Low
2 (mm) 1 (25) Not reported /15 Not reported /10 Not applicable as there is only 1 study. -28.33 (-44.67 to-11.99) 0.007 Moderate
3 (mm) 1 (25) Not reported /15 Not reported /10 Not applicable as there is only 1 study. -2.63 (-3.30 to -1.96) <0.001 Moderate
Keys: MD = mean difference; CI = confidence interval.
Comparison    Hypnosis or relaxation therapy versus no or minimal treatment
Main Results
Compared to no or minimal treatment, hypnosis or relaxation therapy did not show a significant pain reduction for TMD patients (pooled mean difference (pooled MD): -9.16, 95% CI: -23.47 to 5.14). However, hypnosis or relaxation therapy significantly reduced maximal pain (MD: -28.33, 95% CI: -44.67 to -11.99) and improved active (voluntary) maximal mouth opening (MD: -2.63, 95% CI: -3.30 to -1.96).
Comparison: Hypnosis or relaxation therapy versus no or minimal treatment in TMD patients
Outcomes (units) 1 (mm) 2 (mm) 3 (mm)
No. of studies (Total number of participants) 3 (144) 1 (25) 1 (25)
Mean value/No. of participants Intervention Not reported /75 Not reported /15 Not reported /15
Comparator Not reported/69 Not reported /10 Not reported /10
Pooled MD/MD (95% CI) -9.16(-23.47 to 5.14) -28.33 (-44.67 to-11.99) -2.63 (-3.30 to -1.96)
p value 0.21 0.007 <0.001
Overall quality of evidence* Low Moderate Moderate
Keys: MD = mean difference; CI = confidence interval.
Conclusion
Benefits
Compared to no or minimal treatment, hypnosis or relaxation therapy may have beneficial effects on maximal pain and active maximal mouth opening but not on pain threshold among patients with TMD. For outcome 1, the overall quality of evidence is low. Further research is likely to have an important impact on our confidence in this estimate of effect. For outcomes 2 and 3, the overall quality of evidence is moderate. Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
Harms
Among the included trials, two studies did not mention adverse events, and one study reported that there is no adverse events.
Link to Original Article
https://www.ncbi.nlm.nih.gov/pubmed/25905529
The synopsis is based on the following article:
Zhang Y, Montoya L, Ebrahim S, Busse JW, Couban R, McCabe RE, et al. Hypnosis/Relaxation therapy for temporomandibular disorders: a systematic review and meta-analysis of randomized controlled trials. J Oral Facial Pain Headache. 2015 Spring;29(2):115-25.


* Interpretation of quality assessment results:
• Very low: Further research is most likely to have an important impact on our confidence in this estimate of effect.
• Low: Further research is likely to have an important impact on our confidence in this estimate of effect.
• Moderate: Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
• High: Further research is unlikely to have an important impact on our confidence in this estimate of effect.
• Very high: Further research is most unlikely to have an important impact on our confidence in this estimate of effect.

Details of assessment method can be found at Chung VC, Wu XY, Ziea ET, Ng BF, Wong SY, Wu JC. Assessing internal validity of clinical evidence on effectiveness of CHinese and integrative medicine: Proposed framework for a CHinese and Integrative Medicine Evidence RAting System (CHIMERAS). European Journal of Integrative Medicine. 2015 Aug 31;7(4):332-41.