Amalgam removal,what are chances of it coming right off at dentist?

I can't afford a holistic dentist so I have to settle with a dentist who said it'll either be able to come right off, or be drilled. It has been there since childhood n I'm 29 now. Do they often just come right off at the dentist during removal? The other did come off, but not at the dentist. I don't know where it went because Igot a cavity that decayed that tooth. Tweet