Bruxism during the day. The ICDS-R defined sleep bruxism as "a stereotyped movement disorder characterized by grinding or clenching of the teeth during sleep", classifying it as a parasomnia. The second edition (ICSD-2) however reclassified bruxism to a "sleep related movement disorder" rather than a parasomnia. Alternatively, bruxism can be divided into "primary bruxism" (also termed "idiopathic bruxism"), where the disorder is not related to any other medical condition, or "secondary bruxism", where the disorder is associated with other medical conditions. Secondary bruxism includes iatrogenic causes, such as the side effect of prescribed medications. Another source divides the causes of bruxism
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