A crossbite is a type of malocclusion that falls under Class I according to the Dewey-Anderson classification system.
In the field of orthodontics, malocclusion refers to the misalignment of teeth and jaws. Various classification systems help orthodontists categorize these issues to better diagnose and plan treatment. One such system is the Dewey-Anderson classification, which further refines the Angle classification.
Understanding the Dewey-Anderson Classification
The Dewey-Anderson classification system categorizes different types of tooth misalignments, particularly within the broader Angle classifications. It helps specify the nature of the malocclusion within each class.
According to this system, Class I malocclusions are characterized by a normal molar relationship (the upper first molar cusp aligning with the groove of the lower first molar), but with other dental irregularities present. The reference specifies that Class I can be broken down into several types, including those involving crossbites.
Class I Subtypes including Crossbite
Based on the provided reference, the Dewey-Anderson classification includes specific types within Class I that describe crossbites:
| Dewey-Anderson Type | Description | Malocclusion Class |
|---|---|---|
| Type 1 | Crowding of maxillary anterior teeth | Class I |
| Type 2 | Protruding maxillary incisors with spaces | Class I |
| Type 3 | Anterior crossbite | Class I |
| Type 4 | Posterior crossbite | Class I |
| Type 5 | (Details not provided in reference) | Class I |
As shown, both anterior and posterior crossbites are listed as specific subtypes within Class I malocclusion according to this classification system.
What is a Crossbite?
A crossbite occurs when one or more upper teeth bite down inside the lower teeth, either at the front (anterior crossbite) or the back (posterior crossbite) of the mouth. This is the opposite of the typical bite where upper teeth sit slightly outside the lower teeth.
- Anterior Crossbite: Affects the front teeth (incisors, canines). One or more upper front teeth are positioned behind the lower front teeth when biting down. This is sometimes called an underbite, but a true underbite usually involves the entire lower jaw being positioned forward.
- Posterior Crossbite: Affects the back teeth (premolars, molars). One or more upper back teeth are positioned inside the lower back teeth when biting down. This can occur on one side (unilateral) or both sides (bilateral).
Even though a crossbite represents a significant misalignment of specific teeth, if the molar relationship is Class I (as per the Angle classification), the crossbite is categorized as a Type 3 or Type 4 Class I malocclusion in the Dewey-Anderson system.
