Overbite is the extent of vertical ( superior-inferior) overlap of the

maxillary central incisor The maxillary central incisor is a human tooth in the front upper jaw, or maxilla, and is usually the most visible of all teeth in the mouth. It is located mesial (closer to the midline of the face) to the maxillary lateral incisor. As with all i ...

s over the

mandibular central incisor The mandibular central incisor is the tooth located on the jaw, adjacent to the midline of the face. It is mesial (toward the midline of the face) from both mandibular lateral incisors. As with all incisors, its function includes shearing or cutt ...

s, measured relative to the incisal ridges. The term overbite does not refer to a specific condition, nor is it a form of

malocclusion In orthodontics, a malocclusion is a misalignment or incorrect relation between the teeth of the upper and lower dental arches when they approach each other as the jaws close. The English-language term dates from 1864; Edward Angle (1855-1930), ...

. Rather an absent or excess overbite would be a malocclusion. Normal overbite is not measured in exact terms, but as a proportion (approximately 30–50% of the height of the mandibular incisors) and is commonly expressed as a percentage.

Other terms confused with "overbite"

Overbite is often confused with

overjet 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 protrud ...

, which is the distance between the maxillary anterior teeth and the mandibular anterior teeth in the anterior-posterior axis. "Overbite" may also be used commonly to refer to Class II

retrognathia Retrognathia is a type of malocclusion which refers to an abnormal posterior positioning of the maxilla or mandible, particularly the mandible, relative to the facial skeleton and soft tissues. A retrognathic mandible is commonly referred to as a ...

, though this usage can be considered incorrect. This is where the mesiobuccal cusp of the maxillary first molar is situated anterior to the buccal groove of the mandibular first molar; in other words, the mandible (lower jaw) appears too far behind the maxilla. A person presenting with Class II malocclusion may exhibit excessive overbite as well, or may have the opposite problem, which is referred to as openbite (or apertognathia). In the case of apertognathia, and the teeth do not overlap enough or at all—the upper teeth protrude past the lower teeth.

Changing human dentition

American

anthropologist An anthropologist is a person engaged in the practice of anthropology. Anthropology is the study of aspects of humans within past and present societies. Social anthropology, cultural anthropology and philosophical anthropology study the norms and ...

C. Loring Brace Charles Loring Brace IV (December 19, 1930 – September 7, 2019) was an American anthropologist, Professor Emeritus at the University of Michigan's Department of Anthropology and Curator Emeritus at the University's Museum of Anthropological Arc ...

has brought forth a theory that the human overbite of Europeans is only about 250 years old and was the result of the widespread adoption of the

table knife A table knife is an item of cutlery with a single cutting edge, and a blunt end – part of a table setting. Table knives are typically of moderate sharpness only, designed to cut prepared and cooked food. History In early periods in the Wes ...

and

fork In cutlery or kitchenware, a fork (from la, furca 'pitchfork') is a utensil, now usually made of metal, whose long handle terminates in a head that branches into several narrow and often slightly curved tines with which one can spear foods ei ...

. Before the use of

cutlery Cutlery (also referred to as silverware, flatware, or tableware), includes any hand implement used in preparing, serving, and especially eating food in Western culture. A person who makes or sells cutlery is called a cutler. The city of Sheffie ...

, Europeans would often clamp their teeth on a piece of meat and cut off a piece with a knife. When Europeans started using forks and knives, the cutting was done on the plate and the overbite became much more common. Brace also researched the

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...

, who had adopted

chopsticks Chopsticks ( or ; Pinyin: ''kuaizi'' or ''zhu'') are shaped pairs of equal-length sticks of China, Chinese origin that have been used as Kitchen utensil, kitchen and List of eating utensils, eating utensils in most of East Asia, East and Southe ...

900 years earlier and found the instances of overbites increased about the same time the new eating method was introduced. Others further speculate

labiodental consonant In phonetics, labiodentals are consonants articulated with the lower lip and the upper teeth. Labiodental consonants in the IPA The labiodental consonants identified by the International Phonetic Alphabet are: The IPA chart shades out ''labio ...

sounds in human speech were predicated on the development of the overbite.

References

External links

{{Dentofacial anomalies and jaw disease Jaw disorders