TMJ problems were originally thought to stem from dental malocclusion ーupper and lower teeth misalignment ー and improper jaw position. That prompted a focus /on replacing missing teeth and/ fitting patients with braces /to realign their teeth/ and change how the jaws come together.
But/ later studies revealed that /malocclusion itself was an infrequent cause of facial pain /and other temporomandibular symptoms. Rather, as the Boston specialists wrote recently in The New England Journal of Medicine “the cause is now considered multifactorial, with biologic, behavioral, environmental, social, emotional and cognitive factors, alone or in combination, contributing to the development of signs and symptoms of temporomandibular disorders.”
According to the American Academy of Orofacial Pain, the disorder “usually involves more than one symptom and rarely has a single cause.”
Among the “mechanical” causes that are now recognized as distorting the function of the TMJ /are congenital or developmental abnormalities of the jaw; displacement of the disc between the jaw bones; inflammation or arthritis that causes the joint to degenerate; traumatic injury to the joint (sometimes just from opening the mouth too wide); tumors; infection; and excessive laxity or tightness of the joint.