classifcation of malocclusion

Dr. Nagi Hussein Al-Awdi
MSc. in clinical Orthodontics
Classification of malocclusion
Development of Problems

Malocclusion definition
Malocclusion is a condition in which there is a
departure from the normal relation of teeth to the other
teeth in the same arch and/or to the teeth in the
opposing arch (White TC, Gardiner JH and LeightonB).

Definition of classification in orthodontics
➤ Classification in orthodontics is concerned with
the recognition of deviation from a quantitative and
qualitative biological norm.
➤ Classification is also defined as the orderly
reduction of the database to a list of the patient’s
problem (William R Proffit).
Classification employs various diagnostic criteria like
clinical examination, facial photographs, radiographs
and diagnostic casts.

Need/purpose/uses of classification
There are various purposes/uses of classification:
➤ Classification is used for grouping of orthodontic
problems into a category.
➤ Such grouping helps in ease of reference.
➤ Useful in locating the problems which have to be
treated.
➤ Classification helps in diagnosis and treatment plan.
➤ Classification is done for the purpose of comparison
of different types of malocclusions.

Need/purpose/uses of classification
There are various purposes/uses of classification:
➤ Classification is used for communication.
➤ Useful for documentation of the problem.
➤ Used for studying in the prevalence and severity of
malocclusion in population groups.
➤ Used for epidemiological studies.
➤ Training of orthodontist.
➤ To assess treatment effects of orthodontic
appliances.

Methods of recording and measuring
malocclusion/various methods of
classification of malocclusion

Methods of classification can be broadly divided into
two types:
(i) quantitative and qualitative types of
classification and
(ii) intraarch and interarch problems.

I. Classification of malocclusion: quantitative and
qualitative methods

Methods of classification can be broadly divided into
two types:
II. Classification based on intraarch and interarch
problems Malocclusion can also be classified
depending upon the problems present in the same arch
(intraarch) and the problems present between maxillary
and mandibular arches (interarch).

problems Malocclusion
a. Malpositions of an individual tooth or groups of
teeth in the same arch/intraarch problems. This has five
types:
i. Sagittal problems
Labioversion
Linguoversion
Mesioversion
Distoversion

types:
ii. Transverse problems
Crowding
Spacing
Buccoversion
Linguoversion

types:
iii. Vertical problems
Supraversion
Infraversion
iv. Rotated teeth
v. Transposition of teeth

b. Malrelationship between upper and lower arches
or interarch problems
i. Sagittal
Class II malocclusion
Class III malocclusion
ii. Transverse
Crossbites, scissor bite
Midline shift

b. Malrelationship between upper and lower arches
or interarch problems
ii. Transverse
Crossbites, scissor bite
Midline shift
iii. Vertical
Deep bite
Open bite

Angle’s classification of malocclusion
Introduction
➤ Angle’s system of classification is based on the
anteroposterior relationship of the teeth with each other.
➤ Edward Hartley Angle introduced this classification
with the concept of key of occlusion and line of
occlusion.
➤ Maxillary first permanent molar is considered to
be the key of occlusion and Angle stated that the
position of the maxillary first permanent molar is
relatively constant.

Angle’s classification
Angle described three classes of malocclusion
.
• The three classes of malocclusion are based on the
permanent first molar relationship.
• Class II malocclusion has got two types, namely
division 1 and 2.

Angle’s class I malocclusion (neutroclusion)
Molar relation:
• The mesiobuccal cusp of the upper first molar
occludes with the mesiobuccal groove of the lower
first molar.
Canine relation:
• The mesial incline of the upper canine occludes with
the distal incline of the lower canine whereas the
distal incline of the upper canine occludes with mesial
incline of lower first premolar.

Angle’s class I malocclusion (neutroclusion)
Line of occlusion: Line of occlusion will be altered in
the maxillary and mandibular arches:
• Individual tooth irregularities, like crowding,
spacing, rotations, absence of tooth, will be seen.
• Interarch problems, like deep bite, open bite,
proclination or increased overjet, crossbite will be
present.
Class I bimaxillary protrusion
• Class I bimaxillary malocclusion is a condition where
both the key of occlusion and line of occlusion are not
altered, but the upper and lower anteriors are
proclined and exist usually in an edge–edge
relationship.

Angle’s class II division 1 malocclusion (distoclusion)
Molar relation:
• Lower dental arch is distally positioned in relation to
upper arch. The distobuccal cusp of the upper first
permanent molar occludes with the mesiobuccal
groove of the lower first permanent molar.
Class II canine relation:
• The distal incline of upper canine occludes with
mesial incline of lower canine.

Line of occlusion: Altered; other features of class II
division 1 are:
1. V-shaped or constricted maxilla
2. Proclined maxillary incisors
3. Lip trap
4. Exaggerated curve of Spee
5. Deep bite

Class II division 1 subdivision:
• Condition where the class II molar relationship is
unilateral or present only on one side with normal
class I molar occlusion on the other side.

Angle’s class II division 2 malocclusion
Class II molar relation:
• Lower dental arch is distally positioned in relation to
upper arch. The distobuccal cusp of the upper first
molar occludes with the mesiobuccal groove of the
lower first molar.
Class II canine relation:
• The distal incline of the upper canine occludes with
the mesial incline of the lower canine.

Angle’s class II division 2 malocclusion
Line of occlusion:
• Altered.
Other features:
➤ Characteristic lingual inclination of upper central
incisor alone or central and lateral incisors together.
➤ Canine overlaps the retroclined incisors.
➤ Closed bite will be present.
➤ Square-shaped arch.
➤ Exaggerated curve of Spee.

Angle’s class III malocclusion (mesiocclusion)
Class III molar relation:
• The lower dental arch is in anterior relation to the
maxillary arch.
• Mesiobuccal cusp of the upper first permanent
molar occludes with the interdental space between the
lower first and second permanent molars.
Class III canine relation:
• Upper canine occludes with the interdental space
between the lower first and second premolars.

Line of occlusion:
• May or may not be altered.
Other features are:
➤ Reverse overjet or anterior crossbite
➤ Maxillary anterior crowding
➤ Posterior crossbite
Class III subdivision:
• Condition in which class III molar relation is present
only on one side with normal molar relation on the
other side.

True class III:
• This is a skeletal malocclusion. The reasons for
skeletal class III malocclusion are
➤ Retrognathic maxilla
➤ Prognathic mandible
➤ Combination of both
• In this class III, molar relation exists both
in centric occlusion and rest position.

Pseudo-class III/habitual class III:
1. This is not a true class III malocclusion. Due to
occlusal prematurities, when the mandible moves from
rest position to occlusion, it slides forwards into a
pseudo-class III position.
2. These patients show normal molar relationship in
rest position.
3. In centric occlusion, they show class III relation.
4. Cephalogram in both rest position and occlusion
helps to differentiate between true class III and pseudo-
class III malocclusion.

Merits and demerits of angle’s classification/validity of angle’s
classification
Merits
1. Angle’s system of classification is the most traditional
and oldest system still in use.
2. Most practical and easy to comprehend method of
classification.
3. Most popular.
4. Easy to communicate.
5. Widely used for teaching purpose.

classification
Demerits
1. Disregarded the relationship of the teeth to the face.
2. Malocclusion is a three-dimensional problem, but
Angle considered only sagittal dimension.
3. The position of the maxillary first permanent molar is
not stable as stated by Angle.
4. Muscle malfunction and growth of bones were
overlooked. These factors influence the molar position.
5. Classification is not applicable when first permanent
molars are missing.

classification
Demerits
6. Not applicable in deciduous dentition.
7. When there is migration of first molar, classification is
not feasible.
8. Aetiology of the malocclusion is not known.
9. Skeletal problems are not given consideration.
10. Differentiation between dentoalveolar and skeletal
malocclusion is not possible.
11. The classification considers only static occlusion.

Modifications of angle’s classification
There are two modifications of Angle’s classification:
(1)Lischer’s modification and
(2)Dewey’s modification.

Lischer’s modifications
1. Lischer introduced the following names to Angle’s
classification.
Neutroclusion – class I
Distoclusion – class II
Mesiocclusion – class III
2. Lischer also introduced nomenclature to describe
malpositions of individual tooth.
• It consists of adding the suffix ‘version’ to the word.
• These indicate the direction of deviation from the
normal position.

Lischer’s modifications
• Mesioversion – mesial to the normal position.
• Distoversion – distal to the normal position.
• Linguoversion – lingual to the normal position.
• Labioversion/buccoversion – towards the lip or
cheek.
• Infraversion – away from the line of occlusion.
• Supraversion – crossing the line of occlusion.
• Axiversion – wrong axial inclination.
• Torsiversion – rotated on its long axis.
• Transversion – transposition – wrong position in the
arch.

Dewey’s modification
Martin Dewey divided Angle’s classes I and III into
further types:
➤ Class I is divided into five types.
➤ Class III is divided into three types.
➤ Class II has no types.
Class I
➤ Type 1: Crowded maxillary anterior teeth; canines
may be abnormally positioned; other individual tooth
irregularities present.
➤ Type 2: Proclined or labioversion of maxillary
incisors.

Class I
➤ Type 3: Linguoversion of maxillary incisors; anterior
crossbite present.
➤ Type 4: Incisors and canines are normally
positioned. Molars and premolars are in buccoversion.
Posterior crossbites are seen.
➤ Type 5: Mesioversion of molars; molars have moved
mesially due to premature loss of teeth anterior to
molar.

Class III
➤ Type1: Well-aligned teeth and dental arches; edge–
edge relationship exists.
➤ Type 2: Crowded mandibular incisors; normally
placed lower incisors behind the upper incisors.
➤ Type 3: Crowded maxillary incisors; underdeveloped
maxilla; anterior crossbite present.

Simon’s classification
➤ In Simon’s classification, the dental arches are
related to three anthropologic planes.
➤ Since malocclusion is a
three-dimensional problem,
Simon devised this method
of classification orienting dental
arch to three
different planes.
➤ It is a
craniometric
form of classification.

Planes used
1. Frankfort horizontal plane or eye–ear plane (E–E–P)
• This plane is obtained by drawing a line through
the margin of inferior orbit below the eyeball and
upper margin of auditory meatus.
• This plane helps to detect deviations in the vertical
plane.
• Height of the dental arches
and teeth is related to the cranium.
• Dental arch closer to the plane is
called attraction and farther away
from the plane is called abstraction

Planes used
2. Orbital plane (O–P)
• This plane is obtained by drawing a line perpendicular to the
Frankfort horizontal plane at the margin of the bony orbit below
the pupil.
• This plane helps to detect deviations in the sagittal plane.
• Anteroposterior relationship of the
dental arches and axial inclinations
of the teeth are related to cranium.
• Dental arch more anteriorly placed
is called protraction and posteriorly
placed dental arch is called retraction.

Planes used
3. Raphe median plane (R–M–P) or midsagittal plane
• This plane is obtained by drawing lines through midpalatal
raphe at right angle to Frankfort plane.
• This plane helps to detect deviations in the transverse plane.
• Mediolateral relationship of the dental arches and
axial inclination of teeth are related to midline of
the head.
• Dental arch closer to midsagittal
plane is called contraction and
farther away from midsagittal
Plane is called distraction.

Law of canines
• According to Simon, in a normal arch relationship, the
orbital plane passes through the distal aspect of
canine.
• This is called ‘law of canines’.

Interpretations of Simon’s classification of malocclusion

Incisor classification/British standard classification of
incisor relationship
➤ British Standards Institute’s incisor relationship
classification (1983) is used commonly nowadays.
➤ This classification is used without considering the
molar relationship in some cases.
➤ Incisor
classification is prone
for
interexaminer errors.

Incisor classification/British standard classification of
incisor relationship
Class I.
• The lower incisor edges occlude with or lie
immediately below the cingulum of the upper central
incisors.
Class II.
• The lower incisor
edges lie posterior to
the cingulum
prominence of the
upper incisors.

Incisor classification/British standard classification of incisor
relationship
Class II.
• The lower incisor edges lie posterior to the cingulum
prominence of the upper incisors.
Division 1:
• The upper central incisors are proclined or of average
inclination. There is an increase in overjet.
Division 2:
• The upper central incisors are retroclined. The overjet
is usually minimal but may be increased.
Class III.
• The lower incisor edges lie anterior to the cingulum
prominence of the upper incisor. The overjet is
reduced or reversed.

Ackerman–proffit classification
➤ Ackerman and Proffit introduced a new method of
classification to overcome the drawbacks of traditional
Angle’s classification.
• It is based on Venn-Diagrams. It has got 9 groups .
• Ackerman and Profit gave an all-inclusive method of
diagramming and categorizing malocclusions to
overcome the limitations of the Angle’s classification
system in which five characteristics and their
interrelationships are assessed, using a modified
Venn diagram.

Five characteristics assessed are:
1. Alignment
2. Profile
3. Type
4. Class
5. Bite depth.
➤ In this classification a set theory is used where sets
or groups represent malocclusions. A group contained
within a larger enveloping group is a subset of the latter
(enveloping group). A subset has the characteristics of
its outer group also along with its own characteristics.

• Since the degree of alignment and symmetry is
common to all dentitions, this is presented as the outer
envelope or universe (Group 1).
• The profile is affected by many malocclusions, so it
becomes a major set within the universe (Group 2).
• Deviations in three planes are presented by Group 3–
9 which include the overlapping or interlocking
subsets.

GROUPS AND SETS
Group 1
Group 1 is the outer all enveloping group/universe,
which represents alignment of teeth, since the degree
of alignment and symmetry are common to all
directions.
Group 2
Group 2, representing the facial profile, becomes a
major set within the universe (group 1), as the profile is
affected by many malocclusions.

GROUPS AND SETS
Groups 3, 4 and 5
Groups 3, 4 and 5 represent deviations in three planes
of space that is transverse (lateral), sagittal
(anteroposterior) and vertical plane, respectively.
Groups 6, 7 and 8
The overlapping groups 6, 7 and 8 at the center of the
Venn diagram represent more severe problems, with
characteristics from their enveloping groups.

GROUPS AND SETS
Group 9
The group 9 at the exact center would be the most
severe, with involvement of criteria from all the groups
that is alignment, profile, transverse, anteroposterior
and vertical problems.

Advantages of Ackerman-Profit Classification
➤ The advantages of Ackerman-Profit classification are
as follows:
1. The complexities of malocclusion are explained.
2. All three planes or dimensional problems are
included.
3. Profile of the patient is given due consideration
4. This classification helps in complete diagnosis and
differential treatment planning.
5. Differentiation between skeletal and dental problem
is made easily with this system of classifying
malocclusions.

Advantages of Ackerman-Profit Classification
➤ The advantages of Ackerman-Profit classification are
as follows:
6. Arch length problems are evaluated.
7. Ackerman: Profit introduced a new method of
classification to overcome the drawbacks of traditional
Angle’s classification.
8. Readily adaptable to the computer processing.

Disadvantages of Ackerman-Profit Classification
Disadvantages of Ackerman-Profit Classification
1. Etiological considerations are not included in the
classification.
2. This system of classifying malocclusion is based only
on static occlusion. Functional occlusion not included.

Skeletal classification
Skeletal classification considers both the facial skeletal
pattern and also the relationship of the teeth.
Skeletal class I
➤ The bones of the face, maxilla and mandible are in
normal relation to each other.
➤ Maxilla and mandible are in normal relation to the
cranium also.
➤ Profile is orthognathic.
Division 1: Malpositions of incisors, canines o
premolars.
Division 2: Proclined maxillary incisors.
Division 3: Linguoversion of maxillary incisors.
Division 4: Bimaxillary protrusion.

Skeletal class II
➤ Mandibular development retarded when compared
to maxilla.
➤ Distal relationship of mandible to maxilla.
Division 1: Protrusion of maxillary anterior teeth.
Narrow maxillary arch.
Crowding in canine region.
Posterior crossbite.
Retrognathic profile.
Division 2:
Retroclined maxillary central incisors.
Lateral incisors normal or labially placed.

Skeletal class III
➤ Increased growth of mandible
➤ Prognathic profile
➤ Increased mandibular angle.

classifcation of malocclusion

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