Bruxism bruxism), but also possibly grinding, and is often associated with other semivoluntary oral habits such as cheek biting, nail biting, chewing on a pen or pencil absent mindedly, or tongue thrusting (where the tongue is pushed against the front teeth forcefully). There is evidence that sleep bruxism is caused by mechanisms related to the central nervous system, involving sleep arousal and neurotransmitter abnormalities. Underlying these factors may be psychosocial factors including daytime stress which is disrupting peaceful sleep. Sleep bruxism is mainly characterized by "rhythmic masticatory muscle activity" (RMMA) at a frequency of about once per second, and also with
Grinding (gaming) have the potential to be rewarded in the future, and will have no reason to quit. Though grinding is used to provide a "level playing field", this effect could be achieved with any time-consuming behavior that is accessible to all and provides game advancement; The behavior need not be tedious or repetitive, as the term "grinding" generally implies. For example, in a game where advancement is gained by killing monsters, the game could provide such a huge variety of monsters and environments that no two kills are ever the same. As long as all players remained equally capable of killing