Modern medicine refers to nighttime teeth grinding as sleep bruxism and regards it as a major cause of temporomandibular joint disorder. Much like the liver fire described in the Donguibogam, stress is identified as a primary contributor to this condition.
Psychological factors such as severe stress, anxiety, and depression induce changes in neurotransmitters. Numerous studies indicate that an imbalance in neurotransmitters like dopamine and serotonin influences motor nerve activity in the brainstem, causing abnormal contractions of jaw muscles during sleep. Tension and stress consciously restrained during the day manifest unconsciously at night, creating excessive tension in the jaw muscles and placing an undue burden on mastication muscles such as the masseter and temporalis.
When jaw muscles operate continuously throughout the night, morning symptoms can include pain around the temporomandibular joint, headaches spreading to the temples and across the head, and stiffness in the shoulders and nape. Over time, this may result in tooth wear, damage to the gums, and disc damage or displacement within the temporomandibular joint, ultimately progressing into temporomandibular joint disorder where opening and closing the mouth becomes difficult. Just as lactic acid builds up in overused muscles, ongoing tension and fatigue accumulate in the jaw muscles, perpetuating a vicious cycle.
Furthermore, habits such as excessive caffeine intake, smoking, and heavy drinking keep the brain in an aroused state, diminishing sleep quality and aggravating bruxism. Certain medications, including antidepressants, have also been reported to increase the incidence of bruxism. Ultimately, teeth grinding is not merely an inconvenient habit, but an important indicator of one's physical and mental state. Recognizing and managing the underlying stress and tension aligns the insights of the Donguibogam with modern medical understanding.
