classification of mal

Classification of malocclusion By definition, classification is a systematic arrangement in groups or categories according to establ ished criteria . Classification of malocclusion is not orthodontic diagnosis, treatment planning, or prognosis. Rather, classification of malocclusion is a systematic grouping of m a l o c c l u s i o n c a s e s a c c o r d i n g t o established criteria.T h e p u r p o s e o f m a l o c c l u s i o n ' s classification is to:1. Categorize malocclusion syndromes.2. Facilitate communication.3. Comparative reasons.4. Traditional reasons.Several systems of classification of ma l occ l us i on a re ava i l ab l e to the orthodontic profession:

(1) British standard classification (2) Lischer’s terminology(3) Angle s classification (4) Lischer s modifications

British standard classification

Class I :The lower incisors edges occlude immediately below the cingulum plateau of the upper central incisors.

Class II:The lower incisors edges occlude posterior to the cingulum plateau of the upper central incisors.

Class III:The lower incisors edges occlude anterior to the cingulum plateau of the upper central incisors. The over jet is reversed.

Classification of malocclusion p2 Dr.Khaled AboulAzm 2010

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TERMINOLOGY OF MALPOSITION OFINDIVIDUAL TEETH: "LISCHER'STERMINOLOGYIn normal occlusion, the through the buccal cusps and Angle's line ofocclusion passes through the central fossae and along the cingulae of themaxillary teeth, and incisal edges of the mandibular teeth.Lischer used the suffix "version" to identify the malposition- of individual teeth in relation to the line of occlusion. According to Lischer, a malposed individual tooth assumes one or more of the following nine positions1. Labioversion or buccoversion (better termed facioversion): facial to theline of occlusion (i.e., toward the lips or cheeks).2. Linguoversion: lingual to the line of occlusion (i.e., toward the tongue).3. Mesioversion: mesial to the normal position.4. Distoversion: distal to the normal position.5. Supraversion: Past the line of occlusion. Thus, above (in the mandible)or below (in the maxilla) the line of occlusion.6. Infraversion: Away from the line of occlusion. Thus, above (in the

maxilla) or below (in the mandible) the line of occlusion. It is thereverse of supraversion.7. Axiversion: wrong axial angulation (wrong tip) or wrong axial inclination (wrong torque).8. Torsi version: Rotated on its long axis.9. Transversion: Wrong sequential order; transposition.


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Angle classification In 1899 Edward Angle published his ―classification of malocclusion‖. Angle

based his classification upon the mesio –distal relations of the mandibular teeth to the maxillary teeth, dental arches and jaws in anteroposterior plane.

By the introduction of Cephalometric X-ray in 1931 by Broadbent, it showed that the relation of the dental arches and the teeth doesn‘t necessarily reflect the relation of the basal bones in which they lie.

That is why, Angle classification is now only applied to dental arch relations and not as a comprehensive picture of the whole dentofacial complex and skeletal pattern.

Angle based his classification on the hypothesis that providing all the teeth were present, the maxillary first permanent molars could be considered as fixed anatomical points or keys to occlusion‘.

The occlusion of the first molars and canines on both sides of the arch is recorded whether I, II or III.

N.B: The molars and canines positions are often not fully Class І, ІІ, ІІІ but rather in an

intermediate relation. Molars and canines that fall between Class І and Class ІІ are called end to end relationship, and those between Class І and Class ІІІ are called super Class І.

Angle Class І malocclusion

"The lower dental arch is in normal anteroposterior relation to the upper dental arch" as evidenced by the occlusion of the mesiobuccal cusp of the maxillary first permanent molar in the buccal groove of the lower first permanent molar providing no drifting of these teeth has occurred.

In Class I malocclusion the mesiodistal relations of the dental arches are normal but the malocclusion exists elsewhere.

Most cases fall into one of three categories:

(1) Local abnormalities: a) Crowding of the upper and/or lower incisors,


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b) Labial inclination of the upper anterior teeth, c) Anterior cross bite, d) Posterior cross bite, e) Local abnormalities due to premature loss of deciduous molars.

(2) Vertical malrelationships: Excessive overbite (deep bite) or deficient overbite (open bite)

Angle Class ІІ malocclusion:

"The lower dental arch is in distal relation to the upper dental arch" as evidenced by the occlusion of the mesiobuccal cusp of the maxillary first permanent molar in the embrasure between the mandibular second premolar and first permanent molar.

Class ІІ is measured in terms of units. The width of the premolar is considered to be one unit (or half the width of the molar). There are two divisions of class І І designated, division 1 and division 2:


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Division 1:

This is usually characterized by: (1) proclination of the maxillary incisors (2) increased overjet (3) short upper lip and failure of the anterior lip seal (4) V- shaped upper arch (narrow in the canine and premolar region and broad between the molars) (5) deficient mandible and underdeveloped chin. Subdivision: A class ІІ division 1 subdivision malocclusion has a normal occlusal relation on one side of the arch and class ІІ occlusion on the other side

Division 2:

This is usually characterized by: (1) Lingual inclination of the maxillary central incisors and may be overlapped by the maxillary lateral incisors. (2) Broad maxillary arch (3) Deep overbite with the maxillary and mandibular incisors in apparent supraocclusion (4) Normal length upper lip contacting the lower lip but deep mental groove may be present. (5) The mandible is frequently of good size.

Subdivision: Normal occlusal relation on one side of the arch and class ІІ occlusion on the other side.


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Angle Class ІІІ malocclusion "The lower dental arch is in mesial relation to upper dental arch" as evidenced by the occlusion of the mesiobuccal cusp of the maxillary first permanent molar in the embrasure between the mandibular first and second molars.

The maxillary incisors may occlude edge to edge to the mandibular incisors or anterior cross bite may be present or rarely the mandibular incisors occlude lingual to the maxillary incisors but show extreme degree of lingual tipping. This prenormal occlusion may result from excessively large mandible, lack of forward growth of the maxilla, or a combination of both.

true class ІІІ malocclusion the mandible is in centric relation (most retruded position with the condyle in the glenoid fossa as evidenced by X-ray) and can‘t be retruded manually.

• The lower incisors are lingually inclined and the upper are labially inclined.

Pseudo class ІІІ (false or postural): This is not a true class ІІІ malocclusion but its presentation is similar. Here the mandible shifts anteriorly during final stages of closure (acquiring a bite of accommodation) due to premature contact of the incisors or the canines.

• The lower incisors are labially inclined and the upper are lingually inclined.

• Such pseudo or postural class ІІІ may tend, if left untreated, to become established by a further development of the whole occlusion in a class ІІІ relation.

Angle Class ІІІ subdivision: Where normal occlusal relation exists on one side and class ІІІ relation on the other side.

Angle Class IV MalocclusionAs stated earlier, Angle indicated the presence of a fourth class, but didnot give it a Roman numeral. Nowadays, this fourth class is called AngleClass IV. Class IV occurs when the subject has a unilateral Class IIaccompanied with a unilateral Class III. Class IV has neither divisions norsubdivisions.


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Re l iab i l i ty and va l id i ty of Ang le classification: Reliability is defined as "the extent to which an experiment, test, or measuring device yields the same results on repeated trials". Validity is "the conformity to accept biological principles". Angle classification is highly reliable as same results are obtained on repeated clinical examinations. But its validity is questionable due to:

(1) The hypothesis on which it is based is invalid as the maxillary first permanent molars are not fixed points in the skull anatomy.

(2) Cephalometric studies showed that it is possible to have the dental arches in one relation and the basal bone in another relation i.e. Class ІІ dental arches on skeletal Class І.

(3) In Class ІІ the classification doesn‘t differentiate between mandibular retrusion and maxillary prognathism and also in Class ІІІ between the maxillary retrusion and mandibular protrusion.

(4) The classification itself is incomplete as i t c l a s s i f i e s t h e a n o m a l i e s i n anteroposterior direction only ignoring both

the vertical and the transverse directions.

(5) Etiology of the malocclusion hasn‘t been elaborated upon. 14 Advantages and disadvantages of Angle's classification: The classification is greatly reliable, simple, and rap id and requ ires no spec if ic instrumentation. These were the major advantages. The two main disadvantages are:

1. The hypothesis on which the classification is based in invalid.

2. The classification itself is incomplete because it dose not take into account:

a. The vertical and transverse variations in the position of the dental arches.

b. The skeletal pattern malrelationships.

Lischer s modifications of Angle s classification: In 1933 Lischer introduced the following terms to clarify Angle classification: Neutroocclusion or Angle Class І Distocclusion or Angle Class ІІ, Mesiocclusion or Angle Class ІІІ.


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classification of mal

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