As a practicing dental hygienist with 27 years experience, I strongly oppose allowing assisitants to perform scaling.  At this point in time, we have siginificant research and knowledge of the importance of oral health to overall health.  Compromising the quality of care is neglect and will have many negative effects on patients  oral and overall health, as well as the respect of the hygiene profession.  Patients often see their hygienists more than other health care providers( i.e. MD ) and deserve and should receive quality care from a properly educated and trained professional.