Teething in young children is usually 6-8 months after birth, and the first pair of teeth does not come out after 8 months to be considered late teething. The reasons for late teething are many and need to be analyzed in conjunction with the specific situation of the toddler, and cannot be generalized to the following aspects: 1. Genetic factors: For example, if parents or immediate family members within three generations had late teething when they were young, the toddler may have late teething compared to children of the same age. There will also be some differences in the timing of early and late teething for toddlers of different genders, such as boys teething slightly later than girls; 2. Nutritional status: the presence of anorexia, picky eating, and partial eating, resulting in insufficient protein intake, or failure to add milk powder in a timely manner due to insufficient mother’s breast milk, thus resulting in insufficient nutrition and malnutrition, will also affect teething and lead to late teething; 3. Vitamin D and calcium deficiency: the effect on If there is an obvious lack of vitamin D and calcium, the teething time will be significantly delayed compared to other children of the same age. At this time, we should actively supplement vitamin D and calcium, and at the same time, we should get more sunlight, so that the late teething phenomenon can be corrected; 4, disease factors: such as the existence of congenital hypothyroidism, or the existence of congenital ectodermal dysplasia syndrome, rickets, the above diseases can lead to late teething; 5, other factors: there are some late teething, consider the relationship with low birth weight or premature birth, teething The time of teething will also be significantly delayed compared with other children of the same age. If the milk teeth still have not erupted after one week of age, you need to go to the hospital and find out the cause, so as to give timely and targeted treatment.