Absolutely no!  Dental Assistants should not be able to scale teeth in any way, shape or form!  Dental Hygienists have a degree that they earned to give them the right and knowledge level to perform this skill!  Dental Assistants have no eductional degree that gives them the right or skill to perform such therapy!  It is ridiculous and insulting to the dental field to think that someone wants to give a skill to someone that has no skill in this area!  Pathetic!