I suggest you take your child to the Orthodontics Department of Stomatological Hospital for examination. Children's pre-school correction takes a short time and takes effect quickly. It can be cured in a few months, and it takes two or three years to correct deciduous teeth. I have such an example around me.

The normal relationship between maxillary dentition and mandibular dentition is that mandibular anterior teeth are located on the lingual side of maxillary anterior teeth when occluding. And the incisal margin of mandibular anterior teeth is about 1/3 of the lingual incisal margin of maxillary anterior teeth. You may have seen some children's upper and lower incisors have the opposite relationship, and the upper incisors are on the lingual side of the lower incisors. Because the relationship between the two is inverted, it is called "the ground covers the sky".

There are many factors that form "the land covers the sky", such as genetic factors and the influence of some systemic diseases. I would like to remind parents that some factors caused by bad habits are related to you. For example, during lactation, if you lie on your back and feed with a bottle, your jaw needs to be sucked forward, which will cause "all over the sky". For another example, if you don't pay attention to the bad habit of children biting the upper layer to make the mandible protrude, it will gradually cause the front teeth to lift back and the mandible to protrude. Some children have chronic inflammation and hypertrophy of tonsils in the mouth, which makes the mandible stretch forward because of poor breathing, and increases the gap to facilitate breathing, resulting in mandibular protrusion over time. If the baby's incisors are left behind during tooth changing, they should fall off and give way to their successor permanent teeth, but they remain in place. In this way, the eruption position of the subsequent permanent teeth is abnormal. For example, if the incisors in the maxillary breast remain, the maxillary permanent incisors erupt on the palatal side (that is, behind it). When the retained deciduous teeth fall off, the upper and lower jaws bite, and the upper incisors are easily wrapped in the mouth by the lower anterior teeth, thus forming the reverse lifting of individual teeth. Therefore, parents can still play a very important role in preventing the occurrence of "covering the ground".