The single, called Say Cheese (Smile Please), is part of the group's Big Smile campaign, which they're promoting at dentist surgeries around the country.
Dentists taking part in the scheme are getting stickers to give to their young patients, as well as posters for their waiting rooms.
Fast Food Rocker Ria said: "A smile can make you feel good, it can cheer other people up. A smile is worth a thousand words.
"We want to encourage children to look after their teeth, and to make a visit to the dentist more enjoyable."