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
Diamond grinding of pavement pavement. Another important effect of diamond grinding is the considerable increase in surface macrotexture and consequent improvement in skid resistance, noise reduction and safety. The industry can be traced back to an event where a single diamond blade mounted on a concrete saw was used to groove concrete pavement in the late 1940s. Since that early tentative step, concrete grinding, grooving and texturing with diamond blades has developed into what is today a multimillion-dollar industry that is practiced worldwide. One of the first uses of diamond grinding of highway pavement was in 1965 on a 19-year-old section of Interstate 10