Meth mouth

Meth mouth is an informal name for advanced tooth decay attributed to heavy methamphetamine use. According to the American Dental Association, meth mouth "is probably caused by a combination of drug-induced psychological and physiological changes resulting in xerostomia (dry mouth), extended periods of poor oral hygiene, frequent consumption of high calorie, carbonated beverages and tooth grinding and clenching."

Characteristics include:
 * xerostomia (dry mouth): Methamphetamine use may decrease the production of saliva. A lack of saliva's natural protective effects directly leads to increased tooth decay, particularly at the gumline. Many users also smoke tobacco or consume highly sugared soft drinks, worsening the problem.
 * cracked teeth: Methamphetamine induces clenching and grinding of the teeth, leading to wear or cracks.
 * neglect of oral hygiene: This is likely among the most important causes of poor oral health among methamphetamine users. After a prolonged binge, users may sleep for a day or more with their mouths open, exacerbating the problems of poor saliva supply.

Meth mouth is "difficult to distinguish" from a simple case of poor oral hygiene. Dentists are advised to look for "unaccounted for and accelerated decay in teenagers and young adults" and "malnourished appearance in heavy users, because methamphetamine acts as an appetite suppressant."

Contrary to a number of media reports, meth mouth's contributing causes do not include the "corrosive", "acidic" or "caustic" effect of the drug itself on tooth enamel or gum tissue. Jack Shafer of Slate magazine has written a series of articles disputing the role of "chemical" or "contaminant" factors in causing meth mouth.