The term “ugly duckling” refers to a period of growth and development of children’s teeth, namely the period of tooth replacement. As the baby teeth fall out and the permanent teeth grow in during this period, a series of small problems and new phenomena appear, which may make the child look less beautiful, so it is commonly called the “ugly duckling period”. So, what are the problems that usually occur? How to deal with such problems? 1, the incisors are not flush: after the new incisors grow out, the cutting edge is not flush this is a normal physiological phenomenon, with the growth of age and normal physiological function of wear and tear, the incisors of the cutting edge gradually flush. 2, incisors too big: newborn incisors look bigger, which is not to worry. Because, permanent teeth than milk teeth is a normal phenomenon, the child’s face is developing, the face is small, relatively large incisors, with the gradual development of the child’s jaw and face, you will find that the “big teeth” size is appropriate. 3, there is a gap between the incisors: the child’s newly grown two incisors have a gap between the two incisors, some of the two incisors may also be eight-shaped worry that the child’s incisors do not grow well. In fact, as long as you wait until the lateral incisors erupt, this gap will naturally disappear. If the gap is caused by extra teeth growing in the middle of the incisors, you should go to the hospital with X-ray examination to confirm the diagnosis and remove the extra teeth to close the gap. 4, the alignment of teeth: the period of alternation of permanent teeth, the alignment of teeth may not be very neat, parents do not have to worry too much about this. The human body has the function of self-coordination, and the teeth have the potential to align themselves neatly. Before the alternation of permanent teeth is completed, there is no need to rush to orthodontic treatment. Even if you need to correct malformed teeth, you should do it at the age of 13 to 15 after the alternation of permanent teeth is completed. This is when the permanent teeth have erupted to a certain height, so that the production and wearing of various orthodontic appliances will be more accurate and effective. Parents should always check whether the teeth in the child’s mouth have erupted on schedule during the tooth replacement period, as well as whether the neighboring teeth that have not erupted are tilted, shifted, or have malformed teeth. If you find any problems, take your child to the hospital in time. If necessary, you can ask the doctor to take a panoramic oral x-ray to get an idea of the alignment of all the teeth. So is it that because the baby teeth will be replaced by permanent teeth, they are not important? On the contrary, as the saying goes, “If the foundation is not firm, the ground will shake”, the milk teeth are the foundation of permanent teeth, good oral health care in childhood is to lay a good foundation for the future, no one wants to grow up with a mouth full of rotten teeth, missing teeth. Want to lay a good foundation, the following aspects are very important. 1, regularly check the milk teeth and the new permanent teeth: for tooth decay, tooth alignment disorder, anti (commonly known as envelope) and other malformations, or retained milk teeth, etc., should take the child to the hospital in time. 2.Create good oral hygiene habits: we should make children brush their teeth in the morning and evening and rinse their mouth after meals to keep their mouth clean; 3.Eat more chewy food: eating more chewy food promotes jaw development and the natural turnover of permanent teeth and milk teeth. Children’s facial development is related to chewing movement, with the improvement of living standard, some parents let their children eat too fine food because they do not understand the general knowledge about maxillofacial development, in fact, this chewing is not sufficient for children’s maxillofacial development and the prevention of dental caries are very unfavorable. Therefore, we advocate children to eat more chewable and fibrous coarse food, mainly focusing on the following aspects: (1) It is conducive to the digestion and absorption of nutrition: When eating, the food is too fine and does not need to be chewed, so that children develop the habit of being lazy to chew, which is very harmful. The purpose of chewing is to grind the food, and make the food and saliva fully stirred, get preliminary digestion, so that the body can absorb nutrients. Experiments have found that two people eating the same kind of food, chewing people absorb 13% more protein, 12% more fat, 43% more fiber than those who chew. (2) conducive to the normal development of the jaw and face: childhood is a critical period of jaw and face development, if the child only eat fine food, so that the child’s chewing organs do not get full use, so that the jaw and face development does not get due physiological stimulation, so, in childhood to eat more fiber containing coarse food more chewing, to promote children’s jaw and face development is very important. (3) conducive to self-cleaning teeth: chewing can also effectively stimulate the salivary glands to secrete saliva, coupled with rich fibrous food constantly rubbing teeth, play the role of self-cleaning teeth; can also stimulate periodontal tissues through chewing food, enhance the resistance of periodontal tissues to disease. In order to oral health, we advocate appropriate to eat more hard and coarse food, chew slowly, both to help digestion, absorb more nutrients, enhance the ability to resist disease, but also slowly taste the delicacy of delicious, rich life’s pleasure. (4) timely correction of bad oral habits, such as nail biting, lip biting, tongue biting, tongue extension, licking teeth, etc.. These habits may lead to upper (or lower) jaw protrusion (or retraction), open jaw, asymmetric facial development, etc. Therefore, children with the above-mentioned bad habits should be persuaded and educated in time, and if this does not work, they can be corrected with the help and guidance of a doctor.