Expert: Lawrence Spindel DDS, www.lspindeldds.com - 2/19/2009

Question
Sometimes if I yawn with my mouth open too wide, my lower jaw pops out of place.  It actually looks like a ball is going to come through my skin.  It is very painful, but within probably ten seconds goes back in place.  Do you know what the cause of this is?

Answer
Dear Candis,

You appear to be experiencing Temporomandibular joint derangement(also known as TMD).  The Temporomandibular joint has two parts which when moved together properly allows both a sliding movement down and also allows a side to side movement.  In your case it sounds like when you yawn your joint dislocates temporarily.  It is 'popping out' of its normal position.

Clearly you should try if possible to avoid 'over opening' your mouth. Patients with this disorder sometimes do complain that they have pain when they yawn and their jaws can 'lock' temporarily when they open widely or for long periods of time.

Conservative treatment for TMD usually involves the fabrication of a plastic night guard for a patient to wear, will alter the occlusion, open the bite and take some of the stress of the masseter muscles at night by preventing bruxism.  Bruxism and clenching are often thought to be associated with the disorder.

There is a good entry in Wikipedia that I found which you might want to look at. Just copy and paste it into your browser.

http://en.wikipedia.org/wiki/Temporomandibular_joint_disorder

Also I have a page on my website you may want to look at:

http://www.lspindeldds.com/dentist_new_york_night_guards

I hope this information is helpful and please feel free to contact me again with any future dental questions you may have.