If a child is one week old and still has no teeth, it may be caused by non-disease factors such as complementary foods and genetic reasons, or it may be caused by disease factors, so it is recommended to go to the hospital to find out the cause. 1, non-disease factors: 1, supplemental food reasons: children’s supplemental food is too fine and soft or added too late, resulting in children do not exercise to chew function, teeth do not get the corresponding stimulation, will lead to children’s teeth eruption delayed. You can increase the hard food in the complementary food to stimulate the eruption of teeth and promote the growth of teeth; 2, genetic reasons: when the parents have late growth of teeth, the child may also have late eruption of teeth. Second, disease factors: 1, vitamin D deficiency: vitamin D deficiency is likely to cause abnormal calcium and phosphorus metabolism in the body, resulting in delayed development of tooth embryos, thus affecting the eruption of milk teeth, which can be improved by appropriate supplementation of vitamin D and calcium; 2, endocrine disorders: endocrine disorders can also hinder the formation of tooth embryos, which can also lead to late eruption, such as low thyroid function; 3, benign brittle bone disease: benign brittle bone disease can also make The only oral manifestation is the late eruption of milk teeth; 4, hereditary metabolic diseases: not only can lead to late teething of children, but also cause strange appearance, skin and hair abnormalities and other adverse consequences.