About Hygienist: Hygenists do excellent work. Dr. Sada checks their work after they clean it and does a thorough tongue exam for cancer and checks thoroughly all areas of the mouth. they take their time to do it usually 45 mins to one hour. The delta dpi dentist used some kind of ultrasonic machine very pricey that left tons of tartar on my teeth. Manual is the hard way but it is the best way. Trust this dentist and staff!.