Baby Mom: Baby is almost 3 years old, but she has a “habit” that I have been “nagging”, is that she likes to bite her lower lip and not let go, especially when she is sleepy. If you do not sleep deeply, you still bite when you fall asleep. During New Year’s Eve, she also grew her first ulcer in her life, and my mother suspected that she had bitten it. I heard that such a habit also affects teething. I’m so torn, what should I do? How bad is it to bite your lower lip? How can I change this bad habit? The situation described by the parent seems to be that the child’s lip biting is a bad habit during the growth period of the baby. If the child is still frequent after the age of three, it will affect the growth of jaws and teeth. Most children before the age of three have different bad habits of the mouth: some children like to bite the pillowcase or the head when they sleep; some children like to bite their lips; some children like to suck their fingers; and some children like to chew on toys or books. There is no definite cause for these undesirable behaviors, which are basically the result of a variety of factors: for example, the child is insecure, the child is hungry, and possibly the child grinds his teeth when teething, etc. If such conditions occur frequently in children before the age of three, parents should intervene promptly, depending on the situation. If the child has a simple habit problem, parents can remove the object from the child’s mouth after he or she goes to sleep. If the child is unwilling to let go of the mouth, alternative methods can be used, such as using a comfort pacifier, but this is only a short-term induction, not a long-term substitute; if the child is insecurely caused by this habit, parents should have more affectionate communication with the child, stay with the child more often if necessary, and wait until the child goes to sleep before leaving. During the consultation, the youngest child with this bad habit was 2 or 3 months old. The oldest of these children have the habit of biting their mouths until they are teenagers or even adults. Recently, a 5.5-year-old child was seen because he had been biting his lower lip with his upper teeth for a long time, and now the difference between the front and back of his upper and lower teeth has reached more than 10 millimeters, and it is basically difficult for his upper and lower teeth to come together. The parents said that the child had the habit of biting his lips since two or three months, and they did not pay much attention to it at that time, until the situation became serious, then they rushed to bring the child to the hospital to see a doctor. If the child’s lip biting is not frequent, it may just be a habitual problem. But once parents find that their children have been habitually biting their lips, they should pay attention. Because of the long-term biting jaw, teeth tend to grow outward, prone to dental malformations and even skeletal malformations in the mouth. However, there are many children such habits will gradually change, parents are advised to pay attention to the child around the age of 3 years old to observe, if there is an improvement can not be treated. However, if the frequency of lip biting increases instead of decreasing after the age of three, the child must go to the hospital for consultation. Parents should pay attention to the child’s eating and brushing habits, especially careful observation of the child’s hand biting, mouth biting and open mouth breathing. Bad oral habits also include: open-mouth breathing, chewing toys, sucking fingers, and making faces with the chin stretched forward. There is also the mother should not lie flat during breastfeeding, the upper body and lower body to form a certain tilt, do not let the child reach to drink milk; do not let the child lie holding the bottle to eat milk by themselves for a long time, this is also easy to let the child form a chin forward deformity.