Risk factors for temporomandibular (TM) disorders include:

• Stress and anxiety, which can cause facial and jaw muscle tension.
• Repetitive habits, such as grinding your teeth (bruxism), clenching your teeth, excessive gum chewing, eating hard or chewy foods, and nail biting.
• Habits that can cause muscle tension, such as sleeping on one side of your face or with your mouth open, opening your mouth wide when yawning or singing, or holding your head up by cradling your jaw in your hand.
• Injury to the jaw or head. TM disorders can result from a direct blow to the jaw, chin, or head; whiplash to the head or neck; overstretching the jaw during dental work or surgery; or other injuries that may lead to joint damage or muscle tension.
• Age and sex. TM disorders primarily affect people between the ages of 20 and 50. While some studies show that men and women are equally affected, others identify women in their childbearing years as reporting symptoms at the highest rates.²

In the past, malocclusion and orthodontics were thought to cause or contribute to TM disorders. Similarly, orthodontics have been used to treat TM disorders. Despite ongoing controversy, current research suggests that:

• Malocclusion does not cause TM disorders.¹
• Orthodontic treatment does not cause or cure TM disorders.²