Classification of Teeth

The classification of bites are broken up into three main categories:
Class I, II, and III.

Class I:
Class I means that a normal relationship exists between the upper teeth, lower teeth, and jaws or that a patient has a “balanced” bite.

Class II:
Class II indicates that the lower first molar is posterior (or more toward 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 the patient’s profile, with a receding chin and lower lip. Class II problems can be caused by 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 inherited and can be aggravated by environmental factors such as finger sucking. Class II problems are treated by way of growth redirection to bring the upper teeth, lower teeth and jaws into harmony.

Class III:
Class III means the lower first molar is anterior (or more toward the front of the mouth) than the upper first molar. In this abnormal relationship, the lower teeth and jaw project further forward than the upper teeth and jaws. There is a concave appearance in the patient’s profile, with a prominent chin. Class III problems are usually caused by an overgrowth in the lower jaw, undergrowth of the upper jaw, or a combination of the two. Like Class II problems, they may be inherited.

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:
Maxillary-Mandibular Dental Protrusion – teeth: This is an example of a dental malocclusion that may require the removal of teeth for correction.
Maxillary-Mandibular Dental Retrusion – teeth: This is an example of a dental malocclusion that may be treated with expansion rather than removing teeth.

Class 2:
Maxillary Dental Protrusion – teeth: This malocclusion may require the removal of teeth.
Mandibular Retrognathism – jaws: 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.
Maxillary Dental Protrusion – teeth, and Mandibular Retrognathism — jaws: These malocclusions are more difficult to treat due to the skeletal disharmony and may require orthognathic surgery in conjunction with orthodontic treatment.

Class 3:
Mandibular Dental Protrusion – teeth: The lower teeth are too far in front of the upper teeth. This malocclusion is treated with orthodontic procedures that may require the extraction of teeth due to the dental protrusion.
Mandibular Prognathism – jaws: The lower jaw bone has outgrown the upper jaw. This malocclusion is more difficult to treat due to the skeletal disharmony and may require orthognathic surgery in conjunction with orthodontic treatment.