To add to my previous comment, the excuse of a dental hygienist shortage does not make sense as what we are hearing is there are more dentists retiring than new dentists graduating to replace them.  In my area (Northwest Indiana and Chicago suburbs), the competition for jobs is fearce among dental hygienists!   The shortages must be very geographically localized.  This is another reason why more duties should not be taken away from highly skilled professionals with extensive long hours of clinical training.  Please do not lower the standards of healthcare in the dental hygien profession by allowing assistants to scale teeth.