There are many reasons why the gap between two incisors is big, such as physiological phenomenon, malocclusion, supernumerary teeth, ambulatory teeth and so on. 1. Physiological phenomenon: if the gap between two incisors is big in the middle of the teeth, it is a normal phenomenon, usually with the growth of children’s age and gradually get better, especially in the children’s teeth changing period. 2. Malocclusion: mismatch between the width of upper and lower jaw teeth, deep overlap of front teeth, large lip tie, etc., can also lead to a large gap between the two incisors, and can also lead to a decrease in the biting force of the teeth, food inclusions and so on. 3. Multiple teeth: the gap between the two incisors may also be due to multiple teeth, multiple teeth is in addition to the normal teeth in the mouth, and the emergence of redundant teeth, will appear in the two incisors, resulting in large gaps between the teeth. 4. Ambidextrous teeth: Ambidextrous teeth can also lead to large gaps between the two incisors, due to the lack of eruption of teeth into the mouth, may lead to the incisors to the far side of the displacement, resulting in large gaps between the teeth. There are many reasons why the gap between the two incisors is big, after the symptoms, it is recommended to go to the hospital in a timely manner to improve the examination, after a clear diagnosis under the guidance of a professional doctor to take standardized treatment, do not ignore the symptoms, delay the treatment of the condition.