Deep anterior tooth coverage is classified as dental, osseous and functional. Dental anterior deep coverage is clinically manifested as simple anterior deep coverage with labial inclination of upper anterior teeth or presence of scattered gaps, lingual inclination of lower anterior teeth, far-medium or neutral relationship of molar teeth, normal morphological size of upper and lower jaws, and basically normal bone facial shape. x-ray projection measurement of ANB angle is basically within the normal range. Osseous anterior deep coverage is mainly manifested by abnormal size, morphology or positional relationship of the upper and lower jaws in the three-dimensional direction. It may manifest as maxillary protrusion due to overdevelopment or anterior position of the maxilla, and the mandible is essentially normal. It can also present as a normal maxilla with significant abnormalities in the morphology and size of the mandible, such as short mandibular extensions or mandibular bodies, underdevelopment or varying degrees of abnormal development of both the upper and lower jaws. Generally the upper and lower incisors can have varying degrees of labial inclination as a substitute. The upper anterior teeth are upright or lingually inclined, the lower anterior teeth are labially inclined, and the molar relationship is mostly in a distinct distal-medial relationship. The cuspids also show a distocentral relationship with an ANB angle greater than 5°.