Angle's Classification of Malocclusion

Study Notes

Angle's Classification Overview

Angle's classification is a system used to categorize malocclusion based on the antero-posterior relationship between lower and upper teeth.
The classification specifically focuses on the occlusal relationship of all lower teeth relative to all upper teeth.

Main Classes of Malocclusion

There are three primary classes: Class I, Class II, and Class III.

Class I Malocclusion

Lower teeth are normally positioned relative to upper teeth.
The buccal groove of the lower first permanent molar aligns with the mesio-buccal cusp of the upper first molar.
Ideal alignment results in a Class I classification, while crowding indicates a Class I malocclusion.
Mandibular molars are positioned slightly mesial to maxillary molars.

Class II Malocclusion

Lower teeth are distally positioned to upper teeth by half the width of the first permanent molar or the entire width of a premolar.
This relationship continues anteriorly, affecting all occluded teeth.
Class II has two divisions:
- Division I: Prominent upper incisors.
- Division II: Retroclination of one or more upper incisors.
Mandibular molars are distal to maxillary molars.

Class III Malocclusion

Lower teeth are mesially positioned to upper teeth by half the width of the first molar or the full width of a premolar, with lower incisors occluding labially to upper incisors.
Class III can be divided into:
- Hereditary (true) Class III: Results from a pre-normal skeletal pattern.
- Postural/positional/pseudo Class III: Due to abnormal closure path of the mandible.
Mandibular molars are very mesial to maxillary molars.

Class II and III Tendencies

Many malocclusions exhibit signs of Class II or III tendencies when the lower teeth’s relationship to upper teeth is less than a full premolar width.
Descriptions include Angle’s Class II tendency (e.g., end-to-end) and Class III tendency (e.g., super Class I).

Sequence of Classes

Order of types from overbite to underbite:
- Class II (overbite)
- End-to-End
- Class I
- Super Class I
- Class III (underbite)

Key Points on Angle's Classification

Classification is based on the relationship of dental arches at the crowns of teeth, differing from skeletal classifications which consider apical bases.
After premature loss of deciduous teeth, assess malocclusion by mentally repositioning teeth to their original positions before evaluation.
Angle's classification serves as a convenient descriptive tool for malocclusion but does not indicate the underlying causes or treatment options.

Description

Explore the key concepts of Angle's classification system, which categorizes different types of malocclusion based on the positional relationship of teeth. This quiz covers the primary classes, including Class I, Class II, and Class III, as well as their specific characteristics and implications for dental health.