Nine-month-old babies with teething periosteum may need to change the feeding position, correct the mouth breathing habit, use the bite and pry method or wait for about 3 to 5 years old to wear orthodontic appliances for treatment, it is recommended to go to the hospital for examination to choose the appropriate treatment plan for the baby’s condition. 1. Excessive tilting of the baby’s body during feeding or the baby’s habit of falling asleep with the nipple in the mouth can lead to anterior protrusion of the palate and the formation of paronychia. It is necessary to change the tilt of the body during feeding and avoid letting the baby fall asleep with the nipple or pacifier. 2. The baby teething periosteum may be caused by mouth breathing habits, etc., to correct the bad habits, and at the same time check whether the baby has rhinitis, adenoid hypertrophy, etc., and timely treatment. 2. Individual teeth mildly circumcised state can choose to use the bite pry method to correct, you can use moderate bite tongue depressor will teeth bite correction over, should not be violent. 3. Wait until the baby is about 3 to 5 years old is the best time to wear orthodontic appliances to correct the circumference of the sky, may need to wear the front retractor, chin (chin) pocket and other orthodontic treatment.