Being addicted to drugs causes tooth decay, new research confirms.
On average, those with cocaine and cannabis habits had about 3.5 less teeth, the study found.
Adults who regularly used the latter snacked more often and eroded their own teeth, scientists claim.
While some narcotics - including cocaine - caused chemical deterioration when applied to the teeth or gums.
Addicts of both would also clench and grind their teeth, another known risk factor of tooth decay.
A team of Australian researchers combined the results of 28 previous dental studies from around the world.
The study included data of 4,086 patients with known substance use disorders of various drugs.