“Diastema” is a common oral malocclusion in children. Under normal circumstances, when the teeth bite together, the upper teeth are located outside of the lower teeth, wrapping around the lower teeth, which can be interpreted as “sky encircling the earth”. In the case of “encephalitis”, the lower teeth are located outside of the upper teeth, encasing the upper teeth, hence the name “encephalitis”. Due to the abnormal relationship between the teeth and jawbone, “encephalitis” can lead to a variety of problems, such as bite function and aesthetics. Why do mothers and fathers not have it, but their babies will have it? 1. Genetic factors. It is very likely that the parents’ “geodesis” will be passed on to their children. 2, congenital diseases, those who have cleft palate will cause the upper jaw to be underdeveloped, thus causing “geodesic”. 3, systemic diseases, rickets, endocrine disorders or chronic inflammation of the tonsils may lead to. 4, acquired local causes: (1) bad feeding posture, many parents will let the baby lie flat with the bottle sucking milk, when the lower jaw needs to suck forward hard, thus causing the anterior milk teeth rebound. (2) Food structure continues to refine, tooth wear is not enough, may also lead to the “ground envelope” (3) spitting tongue, biting the upper lip, jaw forward and other oral habits may also cause the anterior teeth rebound (4) milk teeth caries may also lead to the loss of tooth space, thus leading to the ground envelope.