The causes of bruxism may vary from person to person and situation to situation. Some of the main ones are: Stress: In stressful situations, some people grind and clench their teeth unconsciously during the night as a way of expressing their concern. Neurological diseases: Although less common, some pathologies of the nervous system can affect the transmission of neuronal signals to the facial muscles, altering chewing. An example of this is stroke. Temperature and climate: In cold conditions, muscle movements generate heat. When grinding teeth, the body activates a defense mechanism to accelerate metabolism and produce heat. Joint dysfunction: In some cases, the temporomandibular joint does not function properly without an apparent specific cause.