Classification of teeth and Face
Classification of Teeth
The classification of bites are broken up into three main categories: Class I, II, and III.
Class I:
Class I is a normal relationship between the upper and lower teeth and a balanced bite.
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Class II:
Class II is where the lower first molar is posterior (or more towards the back of the mouth) than the upper first molar. In this abnormal relationship, the upper front teeth and jaw project further forward than the lower teeth and jaw. There is a convex appearance in profile with a retrusive chin and lower lip. Class II problems can be due to insufficient growth of the lower jaw, an overgrowth of the upper jaw or a combination of the two. In many cases, Class II problems are genetically inherited and can be aggravated by environmental factors such as finger sucking. Class II problems are treated via growth redirection to bring the upper teeth, lower teeth and jaws into harmony.
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Class III:
Class III is where the lower first molar is anterior (or more towards the front of the mouth) than the upper first molar. In this abnormal relationship, the lower teeth and mandible project further forward than the upper teeth and maxilla. The facial profile could have a concave appearance with a prominent chin. Class III problems are usually due to an overgrowth in the lower jaw, undergrowth of the upper jaw or a combination of the two. Like Class II problems, they can be genetically inherited.
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Classification of Face
It is not sufficient to categorize orthodontic malocclusions on the basis of a classification of the teeth alone. The relationship with other craniofacial structures must also be taken into consideration.
Class 1:
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Class 2:
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The lower jawbone has not grown as much as the upper jaw. This example of a Class II malocclusion demonstrates the need for early growth guidance. |
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Class 3:
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