When children are 10-14 years old, they can have their teeth scaled after the replacement of their permanent teeth. When the child is younger, the amount of saliva secretion in the mouth is more, which can play the role of cleaning the tooth surface and rinsing the food residue, and it is not easy to form a large amount of calculus, so it is not necessary to scaling. During the period of deciduous teeth, the enamel is thin and prone to wear, and the child has not yet developed good swallowing and rinsing habits, so it is not suitable for scaling. During the period of replacement of milk and permanent teeth, the roots of milk teeth begin to resorb and the roots of permanent teeth have not yet completed development, there are different degrees of looseness, and the high-frequency vibration of ultrasonic scaler will cause soreness of teeth, and scaling is not necessary. After the replacement of milk and permanent teeth, if the oral hygiene environment is poor and more calculus is produced, scaling can be done once every six months. If the amount of calculus is small, you can scaling once a year.