Finger sucking: Probably every child has had the habit of finger sucking when they were young, and if the child does not correct it by the age of five or six, it can cause significant malocclusion of the child’s teeth. If the thumb is placed between the upper and lower front teeth that are erupting, the normal eruption of the front teeth will be blocked and the upper and lower teeth will not come into contact with each other properly. Tongue licking: The most common problem during tooth replacement is that children often lick their loose baby teeth or newly erupted permanent teeth with their tongues, thus forming the bad habit of spitting out or sticking out their tongues. The tongue will often form a partial opening between the upper and lower teeth, and gaps will appear between the teeth. Lip biting: After the age of 6, children will develop bad lip habits under the influence of adults, the most obvious being lip biting. If the upper lip is bitten frequently it may cause the front teeth to recoil and the lower jaw to protrude forward. Biting the lower lip will cause the upper front teeth to protrude, the lower jaw to recede, and the upper lip will become thick and short, open, with exposed teeth. Lateral chewing: Children are prone to lateral chewing habits in the later stages of their milk teeth development, as the normal chewing function of one side of their teeth is affected by the loss of milk teeth, so they can only eat with the other side. If parents do not correct this over time, it can cause asymmetry in the development of the left and right side of the face. The side that doesn’t chew often is more likely to accumulate tartar because of the lack of food flushing, resulting in tooth decay and other periodontal diseases. Biting: Many children like to chew finger nails or bite the corner of clothes, cuffs, quilt corner, pillow corner and sucking pacifier, etc., because when biting these objects, they are generally fixed in one part of the teeth, thus easily forming a small localized malocclusion of teeth. Bad sleep habits: Some babies are used to sleeping with their elbows, palms, fists and other pillows under one side of the face, or like to often use their hands to hold one side of the cheek, these habits for the child’s young bones, the normal development of the jaw and facial symmetry have an impact on the face. Eat sugar before bedtime: sugar is the nutrient on which the lactic acid bacteria in the mouth survive. Sugar constantly produces lactic acid during the metabolism of bacteria, which corrodes teeth to form cavities. During the daytime, there is a lot of saliva secretion when eating sugar, plus drinking water after eating, which can rinse off the sugar attached to the teeth, but at night when sleeping, there is little water, most of the organs of human body are resting, and saliva secretion is reduced, so eating sugar before going to bed is easy to occur caries. Flossing: The teeth of children are arranged very closely, so it is not easy to embed into the gap of teeth when eating. If the habit of flossing is formed, the gap between teeth will be widened slowly, and the food will be easily embedded in the gap, and the fermentation of the food residue will inflame the gums. In addition, if the toothpicks used for flossing are not hygienic, bacteria will enter the gums when the mucous membrane of the gums is broken during flossing, directly causing the problem of bleeding gums.