Malocclusion
| Malocclusion | |
|---|---|
| Classification and external resources | |
| ICD-10 | K07.4 |
| ICD-9 | 524.4 |
| MeSH | D008310 |
A malocclusion is a misalignment of teeth or incorrect relation between the teeth of the two dental arches. The term was coined by Edward Angle, the "father of modern orthodontics",[1] as a derivative of occlusion, which refers to the manner in which opposing teeth meet.
Contents |
[edit] Presentation
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.[citation needed] Most skeletal malocclusions can only be treated by orthognathic surgery.
[edit] Classification
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.
[edit] 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.[2] According to Angle, the mesiobuccal cusp of the upper first molar should align with the buccal 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.
[edit] Crowding of teeth
Crowding of teeth is where there is insufficient room for the normal complement of adult teeth.
[edit] Cause
Extra teeth, lost teeth, impacted teeth, or abnormally shaped teeth have been cited as causes of malocclusion. Ill-fitting dental fillings, crowns, appliances, retainers, or braces as well as misalignment of jaw fractures after a severe injury are other causes. Tumors of the mouth and jaw childhood habits such as thumb sucking, tongue thrusting, pacifier use beyond age 3, and prolonged use of a bottle have also been identified as causes.[3]
A 2011 paper suggested that "the changes in human skulls are more likely driven by the decreasing bite forces required to chew the processed foods eaten once humans switch to growing different types of cereals, milking and herding animals about 10,000 years ago."[4]
[edit] Treatment
Crowding of the teeth is treated with orthodontics, often with tooth extraction, dental braces, followed by growth modification in children or jaw surgery (orthognathic surgery) in adults. Surgery may be required on rare occasions. This may include surgical reshaping to lengthen or shorten the jaw (orthognathic surgery). Wires, plates, or screws may be used to stabilize the jaw bone, in a similar manner to the surgical stabilization of jaw fractures. Very few people have perfect teeth alignment. However, most problems are so minor that they do not require treatment.[3]
[edit] Other conditions
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.
[edit] Etiology
Oral habits and pressure on teeth or the maxilla and mandible are etiological factors in malocclusion.[5][6]
In the active skeletal growth[7] 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.[8][9][10][11][12]
Pacifier sucking habits are also correlated with otitis media.[13][14]
Dental caries, periapical inflammation and tooth loss in the deciduous teeth alter the correct permanent teeth eruptions.
[edit] References
- ^ Gruenbaum, Tamar. Famous Figures in Dentistry Mouth - JASDA 2010;30(1):18
- ^ "Angle's Classification of Malocclusion". Archived from the original on 2008-02-13. http://web.archive.org/web/20080213164657/http://www.unc.edu/depts/appl_sci/ortho/introduction/angles.html. Retrieved 2007-10-31.
- ^ a b Rosenberg, Jack (2010-02-22). "Malocclusion of teeth". Medline Plus. http://www.nlm.nih.gov/medlineplus/ency/article/001058.htm. Retrieved 2012-02-06.
- ^ Von Cramon-Taubadel, N. (2011). "Global human mandibular variation reflects differences in agricultural and hunter-gatherer subsistence strategies". Proceedings of the National Academy of Sciences 108 (49): 19546. doi:10.1073/pnas.1113050108. PMC 3241821. PMID 22106280. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3241821. Lay summary.
- ^ Klein ET., E (1952). "Pressure Habits, Etiological Factors in Malocclusion". Am. Jour. Orthod. 38 (8): 569–587. doi:10.1016/0002-9416(52)90025-0.
- ^ Graber TM., T (1963). "The "Three m's": Muscles, Malformation and Malocclusion". Am. Jour. Orthod. 49 (6): 418–450. doi:10.1016/0002-9416(63)90167-2.
- ^ Björk A., Helm S., A; Helm, S (1967). "Prediction of the Age of Maximum Puberal Growth in Body Height". Angle Orthod. 37 (2): 134–143. doi:10.1043/0003-3219(1967)037<0134:POTAOM>2.0.CO;2. PMID 4290545. http://www.angle.org/pdfserv/i0003-3219-037-02-0134.pdf.[dead link]
- ^ Brucker M., M. (1943). "Studies on the Incidence and Cause of Dental Defects in Children: IV. Malocclusion". J Dent Res 22 (4): 315–321. doi:10.1177/00220345430220041201. http://jdr.sagepub.com/cgi/reprint/29/2/148.pdf.
- ^ Calisti L. J. P., Cohen M. M., Fales M. H., L. J.; Cohen, M. M; Fales, M. H (1960). "Correlation between Malocclusion, Oral Habits, and Socio-economic Level of Preschool Children". J. Dent Res 39 (3): 450–454. doi:10.1177/00220345600390030501. PMID 13806967. http://jdr.sagepub.com/cgi/reprint/39/3/450.pdf.
- ^ Subtelny J. D., Subtelny J. D. (1973). "Oral Habits - Studies in Form, Function, and Therapy". Angle Orthod. 43 (4): 347–383. http://www.angle.org/pdfserv/i0003-3219-043-04-0347.pdf.[dead link]
- ^ Aznar T., Galán A. F., Marín I., Domínguez A., T; Galán, AF; Marín, I; Domínguez, A (2006). "Dental Arch Diameters and Relationships to Oral Habits". Angle Orthod. 76 (3): 441–445. doi:10.1043/0003-3219(2006)076[0441:DADART]2.0.CO;2. PMID 16637724. http://www.angle.org/pdfserv/i0003-3219-076-03-0441.pdf.[dead link]
- ^ Yamaguchi H., Sueishi K., H; Sueishi, K (2003). "Malocclusion associated with abnormal posture". Bull Tokyo Dent Coll. 44 (2): 43–54. doi:10.2209/tdcpublication.44.43. PMID 12956088. http://www.jstage.jst.go.jp/article/tdcpublication/44/2/43/_pdf.
- ^ Wellington M., Hall C. B.; H; E; F.; K.; J.; G.; W. et al (2002). "Pacifier as a risk factor for acute otitis media". Pediatrics. 109 (2): 351–352. doi:10.1542/peds.109.2.351. PMID 11826228. http://pediatrics.aappublications.org/cgi/reprint/109/2/351.
- ^ Wellington M., Hall C. B.; N.; L.; G.; V.; S. (2008). "Is pacifier use a risk factor for acute otitis media? A dynamic cohort study". Fam Pract. 25 (4): 233–6. doi:10.1093/fampra/cmn030. PMID 18562333. http://fampra.oxfordjournals.org/cgi/reprint/25/4/233.
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