My SIL said to my niece, everytime she asked for it, "ew, yucky" with a grimace and then gave her it. One day Niece announced "ew yucky" and threw it in the bin. She never asked for it back but SIL had fished it out and sterilised it JIC and was planning to go on with "ew yucky" until it sank in.

You could also restrict when she has it? If she talks to you with it in say "I can't understand you with your dummy in" and do not respond to her request until she takes the dummy out to ask? My parents did this to me over my thumb, which i used to have in all the time while talking, and after a few reminders i learned people understood me better without it. Make the dummy a bedtime thing and make sure it stays in the bed, so no dummy in the daytime?

It's a toughie though. Luckily my DD sucks her thumb, which never caused me any dental issues, so i have hopefully escaped the dental stress/bills!

Bx