Classification of Orthodontic Anomalies

From sagittal view: From vertical view: From transversal view:
 * Angle Classification
 * Overjet
 * Overbite
 * 1) Open Bite
 * 2) Deep Bite
 * Scissor Bite
 * (Posterior) Cross Bite
 * Midline Deviation

Angle Classification
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:
 * 1) Division 1 (II/1) --> Anterior teeth protrude


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

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

Overjet

 * Is the abnormal 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:
 * 1) Positive overjet --> Distance >2.5 mm
 * 2) Negative overjet (anterior cross bite) --> Distance <1.5 mm

Overbite
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
Is a rather rare orthodontic anomaly, where the palatal surface of the upper molars rest laterally from the buccal surface of the mandibular molars

(Posterior) Cross Bite
In this anomaly 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
Occurs when the midline of the upper jaw doesn't coincide with that of the lower jaw

Other Orthodontic Anomalies
Is the result of lack of space in the dental arch
 * Crowding

Is the result of excess of space in the dental arch
 * Spacing

Wide interdental spaces

Space between the two central incisors
 * Diastema

The tooth is rotated in the longitudinal axis
 * Rotation

--AlexAlexandropoulos 21:14, 28 October 2011 (CEST)