Meth mouth is a dental condition characterized by severe decay and loss of teeth, as well as fracture, enamel erosion, and other oral problems symptomatic of extended use of the drug methamphetamine (meth). The specific cause of the condition is unknown, although drug-induced xerostomia (dry mouth) and bruxism (grinding of the teeth) are thought to be involved. Other frequently cited factors are poor nutrition and lack of dental hygiene, common among long-term users of the drug. The legitimacy of meth mouth as a unique condition has been questioned because of the similar effects of some other drugs on teeth. Advocates of its status as a unique condition cite the pattern and scope of the decay as distinguishing factors.