Just came across the following Cochrane review on TMJ disorders  (TMD) (Luther et al 2010). Cochrane reviews are the gold standard in evidence based medicine, they do meta-analysis of all the available data. Ben Goldacre (2008), author of Bad Science, pays a long homage to the importance of Cochrane reviews in his book. The text below is the summary from a review done in July 2010. They often come up with surprises (natural health approaches frequently get a kicking), great line at the end: ‘we do not know the real cause of TMD at present’. Not sure what to make of it all really, it certainly affirms how complex an area the jaw is to treat; alignment should not be the only goal of treatment. There may be a few unhappy dentists and brace wearers out there if they come across this review. I assume braces still work for straightening teeth but there is no evidence that they work if the goal is to prevent TMD. (Also just found there is a 2004 Cochrane review (Al-Ani et al 2004) saying there is not enough evidence for whether or not splints worn at night work – wow again. There is also a review saying grinding of teeth surfaces by dentists, ‘occlusional adjustment’, has no evidence to support it relieving TMD (Koh and Robinson 2003))

Orthodontics for treating temporomandibular joint (TMJ) disorders

There is no evidence about the effects of different types of orthodontic braces for problems associated with the joint between the lower jaw and skull. When the joint between the lower jaw and the base of the skull is not working well (temporomandibular disorders (TMD)), it can lead to abnormal jaw movement or locking, noises (clicking or grating), muscle spasms, tenderness or pain. TMD is very common, and it is believed by some that it may be caused by the occlusion (the way the teeth bite), trauma or psychological stress. There is also a belief that the pain associated with TMD is similar, in that respect, to low back pain and may be related to variations of a person’s individual pain perception. Changes in the way the teeth meet can be produced by the use of active orthodontic appliances. This review found that there is no evidence from trials to show that active orthodontic treatment can prevent or relieve temporomandibular disorders adding support to teeth not being part of its cause. It is suspected that we do not know the real cause of TMD at present.

For the full review click here: http://www2.cochrane.org/reviews/en/ab006541.html

References

Al-Ani MZ, Davies SJ, Gray RJM, Sloan P, Glenny A-M. (2004) Stabilisation splint therapy for temporomandibular pain dysfunction syndrome. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD002778. DOI: 10.1002/14651858.CD002778.pub2

Goldacre, B. (2008) Bad Science. London: Fourth Estate.

Koh H, Robinson P. (2003) Occlusal adjustment for treating and preventing temporomandibular joint disorders. Cochrane Database of Systematic Reviews 2003, Issue 1. Art. No.: CD003812. DOI: 10.1002/14651858.CD003812

Luther F, Layton S, McDonald F. (2010) Orthodontics for treating temporomandibular joint (TMJ) disorders. Cochrane Database of Systematic Reviews 2010, Issue 7. Art. No.: CD006541. DOI: 10.1002/14651858.CD006541.pub2

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