I don't think GP meant dentists don't promote it so you keep coming back. Sometimes doctors and pharmacists recommend drugs because they've been paid to promote

I don't think GP meant dentists don't promote it so you keep coming back. Sometimes doctors and pharmacists recommend drugs because they've been paid to promote it, and if nobody's paying to promote this one it's not going to get recommended as often, especially if there's a competing drug that does the same thing.