Methods of removing calculus include manual scraping, ultrasonic cleaning, and periodontal appliance cleaning. Calculus refers to calcified plaque or soft tartar deposited on the teeth, which can be yellowish or grayish-black in color, and is difficult to be removed by daily brushing. 1. Manual Scraping: It refers to scraping off the calculus on the teeth with a manual scraper, which is time-consuming and laborious to operate, and it bleeds a lot and causes severe pain. It needs to be carried out under local anesthesia, and nowadays the dentistry basically does not use this method to remove dental calculus. 2. ultrasonic cleaning: refers to the use of ultrasonic frequency vibration so that the calculus off, this method of bleeding is small and short operation time, cleaning effect is good, ultrasonic cleaning in modern dentistry is more popular. 3. periodontal therapy instrument cleaning: and ultrasonic cleaning principle is the same, only ultrasonic cleaning work is reduced, and the amplitude is slight. This method of cleaning teeth bleeding is smaller, better comfort, and can also remove subgingival calculus, now also more commonly used in dentistry. The impact of calculus on the teeth is very large, it is recommended to go to the hospital regularly every year for dental cleaning.