Classification of Orthodontic Anomalies

Sagittal plane:

Vertical plane:

Overbite

Transversal plane:

Angle Classification[edit | edit source]

Class I

Class I

The mesiobuccal cusp of the maxillary first molar lies in the mesiobuccal groove of the mandibular first molar, but the other teeth may have other anomalies such as spacing, crowding, open bite etc.

Class II

Is also called Distocclusion, or Mandibular Retrognathism
The mesiobuccal cusp of the upper molar is situated anterior to the mesiobuccal groove
Two subdivisions exist:

Division 1 (II/1) --> Anterior teeth protrude, increased overjet

Class II/1

Division 2 (II/2) --> Central incisors are retroclined and sometimes the lateral incisors are seen to overlap the centrals

Class II/2

Class III

Class III

Is also called Mandibular Prognathism
The mesiobuccal cusp of the upper molar lies posterior to the mesiobuccal groove of the first mandibular molar

Overjet[edit | edit source]

Is the distance between the tip of the upper and the tip of the lower incisors in the horizontal plane
The normal distance is ~ 1.5-2.5 mm
We distinguish two types of overjet:

Positive overjet --> Distance >2.5 mm
Negative overjet (anterior cross bite) --> Distance <1.5 mm

Overbite[edit | edit source]

Normally the upper centrals should cover between 1/3 - 1/4 of the anterior surface of the lower centrals

Any disturbance in this coverage can result in:

Open Bite
Deep Bite

Scissor Bite[edit | edit source]

Scissor Bite

Is a rather rare orthodontic malocclusion, where the palatal surface of the upper molars rest laterally from the buccal surface of the mandibular molars
Typical finding in Brodie syndrome

(Posterior) Cross Bite[edit | edit source]

Posterior Cross Bite

In this malocclusion the buccal cusps of the upper molars lie in the opposing central fossa of the mandibular molars (in physiological conditions the palatal cusps of the upper molars lie in the opposing central fossa)

Midline Deviation[edit | edit source]

Midline Deviation

Occurs when the midline of the upper jaw doesn't coincide with that of the lower jaw