Overbite

Overbite, clinically referred to as vertical overlap or deep bite, is the measurement of how far the maxillary anterior teeth overlap the mandibular anterior teeth in the vertical dimension when the posterior teeth are in maximum intercuspation. A normal overbite is approximately 2 to 3 millimeters, representing roughly 20 to 30 percent coverage of the mandibular incisor crown by the maxillary incisors. When this overlap becomes excessive, the condition is classified as a deep overbite, which can range from moderate (4 to 5 millimeters) to severe (6 millimeters or more, sometimes with the lower incisors contacting the palatal mucosa). Deep overbite may result from skeletal factors such as a short lower facial height or excessive maxillary incisor eruption, dental factors including loss of posterior support, or a combination of both.

An excessive overbite can produce a range of functional and pathologic consequences. When the lower incisors contact the palatal gingiva behind the upper incisors, chronic tissue trauma can lead to gingival recession, ulceration, and bone loss in the maxillary anterior region. Deep overbite also contributes to accelerated incisal edge wear on the lower teeth, temporomandibular joint strain from restricted mandibular movement, and aesthetic concerns related to a shortened lower facial profile. Orthodontic correction of deep overbite may involve intrusion of the maxillary or mandibular incisors, extrusion of the posterior teeth to open the bite, or a combination of approaches. In severe skeletal cases, orthognathic surgery may be necessary to reposition the jaws and establish a stable, functional occlusion.

Insurance carriers that provide orthodontic benefits typically require objective documentation of overbite severity as part of the preauthorization process. The millimeter measurement of vertical overlap, supplemented by clinical photographs and cephalometric analysis showing the skeletal and dental components of the deep bite, forms the core of the medical necessity argument. Many plans specify a minimum threshold of overbite severity that must be met before approving treatment, and some require evidence of functional impairment such as palatal tissue trauma or excessive incisor wear. Orthodontic treatment is coded under the D8000 series, and billing teams should ensure that the diagnostic records submitted with the preauthorization clearly quantify the overbite and describe its clinical consequences to maximize the probability of approval.