Malocclusion Classification and external resources ICD-10 K07.4 ICD-9 524.4 MeSH D008310
A malocclusion is a misalignment of teeth and/or incorrect relation between the teeth of the two dental arches. The term was coined by Edward Angle, the "father of modern orthodontics", as a derivative of occlusion, which refers to the manner in which opposing teeth meet.
Most people have some degree of malocclusion, although it is not usually serious enough to require treatment. Those who have more severe malocclusions may require orthodontic and sometimes surgical treatment (orthognathic surgery) to correct the problem. Correction of malocclusion may reduce risk of tooth decay and help relieve excessive pressure on the temporomandibular joint. Orthodontic treatment is also used to align for aesthetic reasons.
Malocclusions may be coupled with skeletal disharmony of the face, where the relations between the upper and lower jaws are not appropriate. Such skeletal disharmonies often distort sufferer's face shape, severely affect aesthetics of the face and may be coupled with mastication or speech problems. In these cases the dental problem is, most of the time, derived from the skeletal disharmony. Most skeletal malocclusions can only be treated by orthognathic surgery.
Malocclusions can be divided mainly into three types, depending on the sagittal relations of teeth and jaws, by Angle's classification method. However, there are also other conditions e.g. crowding of teeth, not directly fitting into this classification.
Many authors have tried to classify or modify Angle's classification. This has resulted in many subtypes.
Angle's classification method
Edward Angle, who is considered the father of modern orthodontics, was the first to classify malocclusion. He based his classifications on the relative position of the maxillary first molar. According to Angle, the mesiobuccal cusp of the upper first molar should rest on the mesiobuccal groove of the mandibular first molar. The teeth should all fit on a line of occlusion which is a smooth curve through the central fossae and cingulum of the upper canines, and through the buccal cusp and incisal edges of the mandible. Any variations from this resulted in malocclusion types. It is also possible to have different classes of malocclusion on left and right sides.
- Class I: Neutrocclusion Here the molar relationship of the occlusion is normal or as described for the maxillary first molar, but the other teeth have problems like spacing, crowding, over or under eruption, etc.
- Class II: Distocclusion (retrognathism, overjet) In this situation, the upper molars are placed not in the mesiobuccal groove but anteriorly to it. Usually the mesiobuccal cusp rests in between the first mandibular molars and second premolars. There are two subtypes:
- Class II Division 1: The molar relationships are like that of Class II and the anterior teeth are protruded.
- Class II Division 2: The molar relationships are class II but the central are retroclined and the lateral teeth are seen overlapping the centrals.
- Class III: Mesiocclusion (prognathism, negative overjet) is when the lower front teeth are more prominent than the upper front teeth. In this case the patient very often has a large mandible or a short maxillary bone.
Crowding of teeth
Crowding of teeth is where there is insufficient room for the normal complement of adult teeth.
Crowding of teeth is recognized as an affliction that stems in part from a modern western lifestyle. It is unknown whether it is due to the consistency of western diets, a result of mouthbreathing; or the result of an early loss of deciduous (milk, baby) teeth due to decay.
Other theories state that the malocclusion could be due to trauma during development that affects the permanent tooth bud, ectopic eruption of teeth, supernumerary teeth, and early loss of the primary tooth.
Other kinds of malocclusions are due to vertical discrepancies. Long faces may lead to open bite, while short faces can be coupled to a deep bite. However, there are many other more common causes for open bites (such as tongue thrusting and thumb sucking), and likewise for deep bites.
Malocclusions can also be secondary to transverse skeletal discrepancy or to a skeletal asymmetry.
In the active skeletal growth mouthbreathing, finger sucking, thumb sucking, pacifier sucking, onychophagia (nail biting), dermatophagia, pen biting, pencil biting, abnormal posture, deglutition disorders and other habits greatly influence the development of the face and dental arches.
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Orthodontics (ICD-9-CM V3 24.7-24.8, ICD-10-PCS 0C?W-X) Diagnosis Appliances Procedures Materials Notable contributors to
the field of orthodontics
Other specialtiesEndodontology - Periodontology - Prosthodontology Organizations Dentofacial anomalies and jaw disease (K07–K10, 524–526) JawDentofacial anomalies/
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