Lying down for breastfeeding may lead to dental eruption in infants and toddlers. Infants are artificially fed with bottles etc. when lying on their backs. Infants may try to wrap their lower lips around the bottle and develop bad habits of jaw protrusion, causing the lower dental arches to exceed the upper dental arches, resulting in the eruption of new upper and lower milk teeth, and inducing functional changes in the masticatory muscle groups. The long-term chewing stimulation of infants can cause excessive development of the mandibular alveolar bone, the maxillary alveolar bone is inhibited, forming a concave face, adults should promptly correct the feeding posture, avoid sleeping with a bottle, etc. After the baby teeth have finished erupting at the age of 2-3 years, you can wear movable orthodontic appliances to push the upper front teeth to the lip to move, inhibit the lower jaw from extending forward, and break the encrustation.