Malocclusion
From Wikipedia, the free encyclopedia
| ICD-10 | K07. |
|---|---|
| ICD-9 | 524 |
| MedlinePlus | 001058 |
| MeSH | D008310 |
A malocclusion refers to the misalignment of teeth and/or incorrect relation between the teeth of the two dental arches.
Most people have some degree of malocclusion, although it isn't usually serious enough to require treatment. Those who have more severe malocclusions may require orthodontic treatment to correct the problem. Correction of malocclusion reduces risk of tooth decay and may help relieve excessive pressure on the temporomandibular joint.
Malocclusions may be coupled with skeletal disharmony of the face, where the relations between the upper and lower jaws are not appropriate. In these cases the dental problem is, most of the time, derived by the skeletal disharmony.
Malocclusions can be divided mainly into three types, depending on the sagittal relations of teeth and jaws:
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[edit] Angle's classification method
Edward Hartley Angle who is considered to be the father of modern Orthodontics was the first one to classify the malocclusion. His based the classifications on the absolute position of the maxillary first molar. According to him the mesio buccal cusp of the upper first molar should rest on the mesiobuccal goove of the mandibular first molar. any variations from this resulted in malocclusion types.
- Class I: Here the Molar relationship of the occlusion is normal or as described before. but the other teeth have problems like spacing, crwding, over or under eruption etc.
- Class II: In this situation the upper molars are placed not in the m.b. groove but anteriorly to it. Usually in the mesio buccal cusp rests in between the first mandibular molars and second premolars.
there are two subtypes
- Class II Divsion 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. Here the retroclined central
- Class III: (prognathism or negative overjet) is when the lower front teeth are more prominent than the upper front teeth. In this case the patient has very often a large mandible or a short maxillary bone.
Other kind of malocclusions are due to vertical discrepancies. Long faces may lead to open bite, while short faces can be coupled to a deep bite.
Malocclusions can also be secondary to transversal skeletal discrepancy or to a skeletal asymmetry.
Many authors have tried to classify or modify the angles systems. these have resulted in many sub types.
