The yellowish tartar behind the teeth is usually tartar, which can be removed by supragingival cleaning, including hand instrument cleaning and ultrasonic supragingival cleaning, as follows. 1. Hand instrument cleaning: use hand instrument cleaning device, put the edge on the root side of the tartar to scrape off the tartar, this way can remove the subgingival calculus. 2. Ultrasonic supragingival cleaning: Use ultrasonic scaler to remove tartar by high frequency oscillation. It should be noted that ultrasonic cleaning is prohibited for patients with old pacemakers, patients with hepatitis, tuberculosis, AIDS and other infectious diseases should not be used, in addition to metal ultrasonic mechanical work head can not be used on the surface of titanium implants, which will damage its surface structure. It is recommended to go to the hospital to receive regular professional treatment.