For your info Dental Hygienst requires at minumum an associates Degree and passing a license exam. It also requires practical experience which in most cases is available thru a college program
I am not sure if Rav Moshe would hold the same on today’s hotplates as they are much hotter than the ones in his time. Today’s hot plates get up to 200 degrees F, wheras the ones 10 15 years ago did not get that hot.