It is normal for one and a half year old babies to have only 6 teeth. Teeth eruption time has individual differences and is related to genetic endocrine food traits. Some children’s teeth grow quickly, while others develop slowly. It is normal for a one-and-a-half year old to have only six teeth, which may be related to the slow development of individual teeth. There is a relationship between tooth growth and bone growth, but the two do not grow in parallel. The slow development of teeth can be judged by combining the height, weight and comprehensive nutritional status of the child, and may be related to calcium, fluoride deficiency, hypothyroidism, and can be supplemented with calcium and vitamin D as appropriate. When teething, individual children may have symptoms such as low fever, increased salivation, drooling and irritability. Parents should pay attention to the care, if the teeth do not erupt for a long time, it is recommended to go to a specialist hospital.