Overjet is the extent of horizontal (anterior-posterior) overlap of the maxillary central incisors over the mandibular central incisors. In class II (division I) malocclusion the overjet is increased as the maxillary central incisors are protruded.
Overjet, also called protrusion, occurs when the upper teeth are located too far in front of the lower row of teeth. It can be caused by a variety of reasons, such as improper teeth alignment, bone deformities, and even poor oral habits. Some dentist and orthodontist may advise their patients to consider correcting overbite. It can usually be corrected through modifications to the bone or through orthodontic hardware, such as braces or a headgear.
There are several different causes of overjet. For example, the molars may be aligned improperly or the upper incisors may be flared. Sometimes there is a problem with the jaw bone itself, such as an upper jaw that is overdeveloped or a lower jaw that is underdeveloped. People, particularly children, with poor oral habits are also susceptible to overbite. For example, children who suck their thumbs, thrust their tongues, or suck on solid objects, such as a plastic toy, may also have an increased likelihood of having their top teeth protrude significantly over their bottom teeth. In many cases, overjet can be diagnosed by a dental professional by the time the patient turns seven or eight years old. A skilled orthodontist will determine when the treatment should begin, typically when all the adult teeth come in. In some cases, an orthodontist may begin treatment before the permanent teeth erupt to prevent damage to other teeth. Even if treatment begins while the baby teeth are still intact, it does not mean that treatment will not need to continue when the adult teeth erupt.
Treatment varies from person to person. Some factors that determine treatment include the severity of the condition, the cause of the condition, and the patient’s age. Treatment may include using orthodontic hardware, such as headgear, braces, palatal expanders, rubber bands, and tooth extractions. If the overjet is the result of a bone deformity, jaw surgery may be required.