From Wikipedia:
"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 dry mouth,extended periods of poor oral hygiene, increased consumption of sugared soft drinks, and teeth clenching and grinding.
Meth mouth characteristics include:
Bruxism (teeth clenching and grinding): methamphetamine induces bruxism, leading to the wear and cracks of tooth enamel.Despite the name "meth mouth", similarly accelerated tooth decay can be caused by the abuse of other stimulants with similar actions, such as amphetamines, cocaine and methylphenidate (ritalin).
Oral hygiene neglect: methamphetamine users often neglect oral hygiene.
Hyposalivation (dry mouth): a lack of saliva's natural protective effects directly leads to increased tooth decay, particularly at the gum line.
Prematurely aging faces of methamphetamine users
I do not recall getting oral care advice with my scrip for amphetamines. But I don't remember much from that time. Did your doctor tell you this?