I feel compelled to post on this topic because it is a topic I know so well.

Sadly it's true that many types of drugs and most/all opioids will precipitate an unhealthy oral environment primarily due to dryness. When the oral skin/gums/tongue have less than a normal healthy moisture level, decay and cavities will be more likely even if you brush your teeth immediately after you finish eating, every time you eat.
I'm wondering if there are any opioids that do not have any capacity to dry the mouth. Anyone know?
Potential remedies to dry mouth previous posts have mentioned all sound good to me except sucking on candy. While the moisture and saliva created by the candy would be a positive, the decay coming from the sugar within that saliva would make sucking candy a net negative. While it's inconvenient and annoying to have a dry mouth, I am more concerned about the tooth decay resulting from the dry mouth than the irritation factor of the dry mouth itself.
Perhaps a sugar-free candy? I'm not sure if sucralose is bad for teeth.
Another way to combat dry mouth is a dry mouth oral paste or gel. In a way it fucking sucks donkey balls because it has a texture reminiscent of sex jelly. It does work though.
Maybe someone should poll the people using this site on how many cavities they have had filled and how many times they have required major dental work.