Q1) If someone has been using heroine for three years is that long enough for the teeth to begin to decay/crack? Also they're 19 and were never taken to a dentist as a child, and up until now didn't care about dental hygiene.
Q2) If the drug has effected the teeth would it be safe to begin brushing them once they stop usiing? Or would it cause them to hurt or crack more?
I'm writing a story and have no experience and know no one with experience with heroin, so I need help developing details for legitimacy. Thank you for your help!