Feel free to let Frank know that you have a friend with many crowns, which is what comes after fillings. When I was young nobody explained that the fillings are always temporary. They need to be replaced every few years. Eventually you can no longer fill the cavity and you get a crown. And that will likely be replaced more than once also.
Unless he really likes Novocain and being drilled on, he should learn his lesson now.
The ability to speak several languages is an asset, but the ability to keep your mouth shut in any language is priceless.
And easier if your teeth are all rotten!
I’ll just tell Frank to brush his teeth!