As a "Prophy Tech" in the USAF in the 70's I was trained on the job to scale teeth and really thought I knew what I was doing...It wasn't until I went to Dental Hygiene school that I realized all the damage I had been doing by just scaling supragingivally!  We were required to refer patients with subcalculus to the Periodontist but because my training was so limited I wasn't able to recognize when the need was there.  I apologize to those that did not receive the proper care they deserved and I sincerely hope that this backslide of care will not be allowed.