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
The Grinding Wheel has received generally positive reviews from critics. Blabbermouth.net writer Ray Van Horn Jr. gave the album a rating of nine-and-a-half out of ten, and said, "If you think Overkill expended its tanks producing output with such astonishing velocity, you don't know this band very well. For its eighteenth album, "The Grinding Wheel", Overkill does the unthinkable: it outdoes itself. Consider that some fans dropped off after 1991's "Horrorscope", which is those poor saps' folly. For the diehard wrecking crew, "The Grinding Wheel" is going to be a gift to cling to throughout 2017." He finished his review, saying that the