Deep overlap is a malocclusion caused by abnormal development of the maxillary and mandibular arches and/or the vertical direction of the upper and lower jaws. It is mainly caused by the overgrowth of the lower teeth or by the upper teeth opening forward. It can be obvious that the length from the bottom of the nose to the bottom of the chin is shorter than the length of the front two chambers, and the gums are more exposed when smiling, which means that the jaw is receding and there is a gummy smile. Generally, as long as the above symptoms are met, it can be judged as deep bony overlap. In addition, patients can also go to the hospital to take panoramic X-rays, which can clearly diagnose deep bony overlap. Clinically, deep overlap is divided into 3 types, different degrees of deep overlap and its treatment methods are different, as follows: 1, type I treatment of deep overlap: keep the height of the anterior alveolar bone unchanged, focusing on raising the height of the posterior teeth. The use of maxillary movable orthodontic appliance with planar guide plate and dental pad, starting from the last tooth one by one to adjust the dental pad, after the posterior teeth to increase the height, and then the correction of the anterior teeth lingual misalignment and posterior teeth distal center; 2, type II treatment of deep overlap: maintain the height of the posterior alveolar bone, depress the anterior teeth, if the anterior teeth overlap is not too deep, fixed orthodontic appliance or movable orthodontic appliance can be used to push the upper and lower anterior teeth to the lip; 3, type III Type III deep overlap treatment: take the approach of depressing the anterior teeth and elevating the posterior teeth orthodontic treatment, available movable orthodontic appliance, can also use fixed or functional braces, need to choose according to the patient’s situation.