So this comes up frequently
In most states the DPA is worded in a way that dentists and specialists may perform procedures "within the scope of their practice"
This leaves it up to interpretation...so if a periodontist is placing crowns he will be fine unless he is sued...bc once the professional consultant becomes the witness it will not be hard to convince everyone that a crown is no longer within the scope of a periodontist
The law is always nebulous...if you want to hear a lot of bs ask your dental school faculty about obtaining informed consent