“Meth mouth” is characterized by severe tooth decay and gum disease, which often causes teeth to break or fall out. An examination of the mouths of 571 methamphetamine users showed:
96% had cavities
58% had untreated tooth decay
31% had six or more missing teeth
The teeth of people addicted to methamphetamines are characterized by being blackened, stained, rotting, crumbling and falling apart. Often, the teeth cannot be salvaged and must be removed. The extensive tooth decay is likely caused by a combination of drug-induced psychological and physiological changes resulting in dry mouth and long periods of poor oral hygiene. Methamphetamine itself is also acidic.

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