I have noticed that some dentists argue that dental assistants are cleaning cement from newly inserted crowns, and should therefore be allowed to scale perio I patients.  I don't think we're comparing apples to apples here.  Cleaning cement from one tooth is a far cry from total patient care during a hygiene visit.  Please don't be under the assumption that all perio I patients are "easy."  Hygienists are very carefully trained to recognize oral manifestations of diseases, symptoms of xerostomia, medical complications that may require pre-medication (regardless of perio status), and is versed in giving oral health education specific to each individual patient.  Also, if dental assistants are limited to supra-gingival scaling, how will they know for sure there are no developing areas of concern to the perio health if there is no probing?  What about exploring subgingivally for residual calculus?  Monitoring perio health is an ongoing process that should be done under the direction of those specially educated to do so.  It's not unheard of for a perfectly healthy patient to present with the onset of problems due to changes in their systemic health - please let hygienists continue to be responsible for helping all patients maintain optimal oral health so no one "slips through the cracks."  Our pharmacology instructor left us with one very important point upon graduation - "It's not just a cleaning.  It's overall health."