Since the board is delegating direct patient care and tasks to assistants in which patient health and safety are at risk, it would seem in the best interest of patient safety to want to keep record of these technicians to keep the standard of care upheld. 

Opting to refuse the responsibility and impart that on the individual dentists is not in the best interest of the public. Instead the board is choosing to protect the special interests of the dentists they represent. 

Dental assistants currently have no requirement to be certified, no requirement to be trained in infection control, or in occupational safety and PPE.  Training them on the job without regulations is a reckless assault to patient and public health. A nail technician has to undergo training, testing, and have license to cut and paint nails, but not a dental assistant?

Supragingival scaling in itself, is incomplete care. Subgingival biofilms and build up must be removed to reduce inflammation and prevent the disease process from progressing. This model will not improve access to care but instead promote disease and further dental hygiene burnout by increasing the workload of the RDH  as they are left to debride more leftover tenacious and neglected subgingival build-up.