Myofunctional Therapy (usually in conjunction with bodywork) is effective at treating disorders of the jaw, by restoring normal function to the oral muscles. Having the tongue, lip, cheek, throat, face and neck in functioning correctly and in balance, helps to alleviate pressure from the jaw, and increase mandibular mobility, alleviating jaw discomfort and related symptoms.
Further reading and research can be found at:
The Effect of Jaw Position on Measures of Tongue Strength and Endurance ://www.ncbi.nlm.nih.gov/pmc/articles/PMC3523665/