If the deep overjet is not corrected, it will become more and more severe as the teeth wear out. 1. Deep overjet is a kind of malocclusion, which is caused by congenital factors, bad oral habits, abnormal tooth replacement and other acquired factors, and is mainly manifested by the fact that the incisal edge of the upper front teeth exceeds the length of the crown of the lower front teeth by more than 1/3 or the occlusion of the lower front teeth is located in the tongue of the upper front teeth by more than 1/3. 2. If not corrected in time, with the growth and development of the skeleton, the abrasion of the back teeth becomes heavier and heavier, and the deep overjet will seriously affect the development of the soft and hard tissues of the teeth and jaws, resulting in the underdevelopment of the lower jaw and the backward shrinkage, the upper jaw protrudes forward, and the open lips and teeth are exposed, or even a bird’s beak-like deformity. It may also affect the normal function of the temporomandibular joints and even cause organic lesions of the joints. It is recommended to correct the deep overjet in time. Children can have growth modification, while adults usually need orthodontic treatment.