Classification of malocclusion (4)

   Introduction
  Difference between normal
occlusion and malocclusion
  Definitions
  Categorizing of malocclusion
  Classification of malocclusions
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Introduction
•                                           The term orthodontics was derived from
Greek word “Ortho” means correction “dontos”
means teeth.
•             The term was coined by Le. feloun in
1839.
•             Orthodontics is one of the oldest branch of
specialization of dentistry. Its importance came
into existence simultaneously with dentists for
more than 2000 years.
•              Aristortle - was the first writer who
•

John Hunter was the first to describe about
normal occlusion.
Sameul.S.Flitch was the first to classify
malocclusion.
Carabelli was the first to describe about
abnormal variation of arches.

ANDREWS SIX KEYS OF OCCLUSION.
1.  MOLAR RELATION.
2.  CROWN ANGULATON.
3.  CROWN INCLINATION.
4.  ROTATION.
5.  TIGHT CONTACTS.
6. PLANE OF OCCLUSION.

Kakosi defined various norms to describe malocclusions
1.DIAGNOSTIC NORM.
2.OBJECTIVE NORM.
3.BIOMETRIC NORM.
4.SUBJECTIVE NORM.
5.THERAPEUTIC NORM.

Definitions:
Overjet: Is the horizontal overlapping between the
upper and the lower anterior teeth.
Normal = 2 – 3 mm.

Overbite: It is the vertical overlapping with the
upper and the lower anterior teeth.
Normal = 2 – 3 mm.

Protrusion/Proclination: Condition where the
maxillary or mandibular teeth are placed anterior
than the normal.

Retrusion: Condition where the maxillary/
mandibular teeth are placed posterior to the normal.

Crowding: Condition where there is positional
irregularity of tooth crowns.
Spacing: Condition when there are spaces present
in between the tooth.


Crossbite: It is a condition where the lower teeth
overlap the upper teeth (due to abnormal bucco-
lingual or labio-lingual relationship of the teeth.

Openbite: Condition where there is lack of vertical
overlapping of the teeth.

CATAGORISING MALOCCLUSION.
IT IS DEVIDED INTO THREE GROUPS.
1.DENTAL DYSPLASIA
2.SKELETO DENTAL DYSPLASIA
3.SKELETAL DYSPLASIA.
ONE MORE WAY TO CATAGORISE.
1.HOMOLOGOUS MALOCCLUSIONS
2.ANALOGOUS MALOCCLUSIONS.


CLASSIFICATION OF MALOCCLUSION
Classification can be defined as grouping of clinical cases of
similar appearance for ease of handling. It is not a system of diagnosis
or method of determining prognosis or a way defining treatment.
Purposes of classification.
1.identify problems.
2.ease of referance .
3.helps in comparision .
4.communication.
5.better treatment plan.
6.develop a strategy to manage group of similar cases.
7. Recall past difficulties with similar cases.

How to classify:
Even after 100 years after Dr. E. Angle gave his
system of classification (1899) and ever though there
were many modification of his system and introduction
of other systems of classification of malocclusion, but
even still today we follow the angles system of
classification of malocclusion for the ease of it.
We know that occlusion is the end result of the
interaction of 3 systems namely, dental, skeletal and
neuromuscular. Any alteration in any one of the above
systems can lead to malocclusion, which can manifest
in the primary, mixed or the permanent dentition.

Strang (1938) has suggested few steps on how to study and
to give a proper classification;
1.     -The cusp fossa, ridge groove, relationship of the teeth
and the axial inclination should be taken into consideration
along with the midline relationship.
2.      -Look for any rotated posterior teeth.
3. -Look for premature loss of teeth, extracted or
congenitally missing teeth.
4.      -The facial pictures should be studied properly.
5.     -There should be proper interpretation of the tracing
from a standard lateral cephalogram.

Classification of malocclusion:
•       Basically there were only 2 approaches to
classifying malocclusion.
•                 The first method considered etiology.
•            Kingsley in 1880’s focused on causative
factors in his pioneering work. However since the
etiology of a malocclusion is frequently multifactorial
and often not discernible his classification was not
widely accepted.
•            Morphologic classification are complicated by
the wide variation found in the human occlusion and
anatomic forms., the variation in severity of
malocclusion and the frequent overlapping of
numerous problems in a patient.
•             www.indiandentalacademy.com

          Angle believed that the maxillary first molar is
the key to occlusion because;
Th They are the largest teeth
                Firmest in their attachment
                Have a key location in the arches
     Help determine the dental and skeletal vertical
proportions due to their lengths of their crown.
           Occupy normal position in the arches far more often
than any other teeth because they are the first permanent
teeth and are less restrained in taking their position.
           More or less control the position of other permanent
teeth anterior and posterior to them.
            Have the most consistent timing of eruption of all
the permanent teeth. www.indiandentalacademy.com

Today we have Angles classification as;
 Class I malocclusion, where the upper
first permanent molars mesio-buccal cusp
occludes in the buccal groove of the mandibular
first permanent molar, and where the patient
may exhibit crowding, spacing or rotations.


Class II malocclusion, where the upper first
permanent molars disto-buccal cusp occludes in the
buccal groove of the lower first molar, which is
further divided into class II division 1 and class II
division 2.

In class II division 1 is characterized by the molar
relationship being the same but where as there is
proclination of the upper anteriors.

In class II division 2 is characterized by the molar
relationship being the same, but where as the central
incisors are retroclined and the lateral incisors are flared or
where the central and lateral incisors are retroclined but
the canines are flared and then there is the class II
subdivision where in there is class II molar relationship on
one side and there is class I molar relationship on the other
side.


Class III malocclusion can either be a true class III or a
pseudo class III. The class III malocclusion exhibits a
molar relationship where the mesio-buccal cusp of the
upper first permanent molar occludes in the interdental
space of the lower first and second permanent molars.
Where as the pseudo class III produced by the forward
movement of the mandible during jaw closure.

Drawback’s of Angles classification:
1.First permanent molars are not fixed points.
2.skeletal and dental malocclusion are not differentiated.
3.classification is based on only one relation.
4.cannot be used if all first permanent molars are extracted.
5.Severity of malocclusion cannot be judged.
6.does not differentiate true and psuedo class III malocclusions

Lischer’s modification of Angles classification:
-Lischer termed Angles I, II and III as neutro-occlusion,
disto-occlusion and mesio-occlusion. Other than these he
added a few more terms in the classification of
malocclusion such as,
    -Bucco-occlusion: Buccal placement of a tooth or a
group of teeth.
  -Linguo-occlusion: Lingual placement of a tooth or a
group of teeth.
     -Supra-occlusion: Erupted beyond normal level.
     -Infra-occlusion: Not erupted to normal level.
   -Mesio and disto version: Placed mesial or distal to
normal occlusion.
     -Axiversion: Abnormal inclination of a tooth.
-Torsiversion: Tooth rotated around its long axis.www.indiandentalacademy.com

Dewey’s modification of Angles classification of
malocclusion:
Dewey sub-classified class I into 3 types and later Anderson
added two more types, they are as follows;
Type 1: Class I molar relationship with crowded anterior
teeth.
Type 2: Class I molar relationship with protrusive maxillary
incisors.
Type 3: Class I molar relationship with anterior cross-bite.
Type 4: Class I molar relationship with posterior cross-bite.
Type 5: Drifting of permanent first molar due to extraction
of deciduous second molar.

No modifications for classII and three
modifications for classIII.
classIIItypes
TypeI-normal inscisal over lapping.
TypeII-edge-edge inscisor relation.
TypeIII- Incisors are in cross bite relation

Simon’s classification of malocclusion:
In 1920’s Simon of Germany (Berlin) developed a
gnathostatic system using an elaborate facebow and
impression orienting apparatus to create study casts that
were cephalometrically oriented to the patient orbital plane
(A line drawn from orbitale perpendicular to the FH plane).

1.Frankfurt horizontal plane
2.Orbital plane
3. Median saggital plane
Simon anthropometric planeswww.indiandentalacademy.com

Bennett’s classification of malocclusion (1912):
Sir Norman Bennett an Englishman recommended
classifying malocclusion in the sagittal, transverse and
vertical planes of space. He developed a classification that
also uses class I, II, and III but he divides malocclusion by
etiology rather than morphology.

Here class I, denotes abnormal position of one or more
teeth due to local causes. Class II denotes abnormal
formation of a part or whole of either arch due to
developmental defects of bone. Class III denotes abnormal
relationship between upper and lower arches and abnormal
formation of either arches.

Ricketts and others:
Rickett’s and others, working with the
Rocky mountain data system in the late 1960’s
designed a computerized cephalometric analysis
that classified malocclusion from a cephalometric
radiograph rather than from casts.

Ackerman and Proffit (1969):
In 1969 Ackerman and Proffit, acknowledging
the limitations of Angle’s classification proposed a
new classification scheme that combines five
descriptive characteristics for malocclusion.
           Alignment in occlusion view.
           Profile and soft tissue.
           Transverse plane deviations (cross bites)
           Sagittal plane deviations (antero-posterior)
           Vertical problems of bite depth.

Venn diagram representing Ackerman profit classification

British standards institute classification:
British standards incisors classification
A. Class I
B. Class II Div 1
C. Class II Div 2
D. Class III

Class I: The lower incisor edges occlude with or lie
immediately below the cingulum plateau of the upper
central incisors.
Class II: The lower incisor edges occlude with or lie
immediately below the cingulum plateau of the upper
incisor. There are 2 subdivision of this category.

Class III: The lower central incisors edges lie anterior to the
cingulum plateau of the upper incisors. The overjet is
reduced or reversed.

Ballard’s classification:
This is a classification used to know the various
skeletal relationship. It is used more accurately at the
chairside. Accordingly different skeletal classes are;
Skeletal class I: This inclination of the teeth is normal and
the dental base relationship is also normal. The upward
projection of the axis of the lower incisors would pass
through the crown’s of the upper incisors.
Skeletal class II: The lower apical base is far too back. The
lower incisor axis would pass palatal to the upper incisor
crown.
Skeletal class III:
The lower apical base is placed relatively too far
forward, the projection of the lower incisor axis would pass
labial to upper incisor crowns.www.indiandentalacademy.com

Cephalometric classification of malocclusion:
           As we all know cephalometrics is an integral part of
classification of malocclusion basically skeletal as well as
dento alveolar. Cephalometric analysis helps us see the
changes achieved before and after treatment. Therefore it is
very important for us to reach to an classification of
malocclusion either dento-alveolar or skeletal with the help
of cephalometrics.
-Class II
-Class III
                      - Open bite
                      -Deep bite

Elsasser:
Elsasser published a paper in JCO in 1978 –
orthodontic assessment by the numbers. He uses 3
groups of numbers to describe the extent of malocclusion
in quantitative terms
Group 1:Shows the relationship of maxillary and
mandibular incisors
Group 2: Represents the relationship of the maxillary
cuspids to the mandibular arch.
Group 3: Represents the mesio-buccal relationship of the
maxillary and the mandibular permanent first molar and
the bucco-lingual relationship of the maxillary and
mandibular permanent first molars to each other.

Katz modification of Angle’s classification:
Morton I. Katz published two papers in AJO. DO
in August and September, 1992 – Angles classification
revisited (is current use reliable Part-I and Part II).
A

A


A Newly defined type of malocclusion.
Pseudo class I-The pseudo class I is clearly
distinguishable
From Angles class I as fallows
1.Mesial rotation of upper first and second molars.
2.crowding of lower incisor.
3. Lack of space for lower canine to erupt.
Causes of development of pseudo class I.
1.fallowing uncontrolled eruption.
2.in adequate treatment planning.www.indiandentalacademy.com

Limitations of classification systems:
However useful classification
systems but they must not impede our
flexibility to adopt to new knowledge.
a. None are truly inclusive.
b. All are static in concept.
c. Most are narrow in focus and
perspective.
d.There is a tradition of misuse and mis-
application. www.indiandentalacademy.com

References:
1.      - Andrew L.W.: “Straight wire – The concept and
appliance”.
2.             - Proffit W.R.: “Contemporary orthodontics”. 3rd
Ed.
3.                -Graber T.M.: “Orthodontics”. 3rd
Ed.
4.                -Bishara: “Textbook of orthodontics”. 1st
Ed.
5.                -Moyers: “Hand book of orthodontics”. 4th
Ed.
6.                -Rakosi: “Colour atlas of orthodontics”.
7.           -Andrew L.W. (1976): “6 key’s to normal occlusion”.
Am. J. Orthod.; 62(3): 296-309.

1.   Katz I. (1990): “The hundreds years dilemma”. Quint.
Int.; 21(5): 407-413.
2.   -Ronald J. (1989): “Ambiguities of Angle’s classification”.
Angle Orthod.; 4: 295-298.
3.  -Ackerman J.L. and Proffit W.R.: “The characteristic of
malocclusion”. Am. J. Orthod.; 56(5): 443-454.
4. -Katz I. (1992): “Angle’s classification revisited - Is
current use reliable”. Am. J. Orthod. Dentofac. Orthop.
Aug-Sept.
5.  -Elsasser W.A. (1978): “Orthodontic assessment by the
numbers”. J. Clin. Orthod.; Feb.: 116-112.

THANK YOU

Classification of malocclusion (4)

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