Classification of malocclusion (2)

CLASSIFICATION OF MALOCCLUSION
www.indiandentalacademy.com

CONTENTS
• DEFINITIONS
• PURPOSE OF CLASSIFYING
• SYSTEMS OF CLASSIFICATIONS
• LIMITATIONS OF CLASSIFICATION SYSTEMS
• ANGLE CLASSIFICATION REVISITED

Definitions
Occlusion:
The changing interrelationship of the opposing
surfaces of max & mand.teeth occuring during
movements of mand & the terminal full contact of
max. & mand arches.
Not a static condition
Normal occlusion [angle]: evenly placed rows of
teeth arranged in graceful curve with harmony
between upper & lower arches

ANGLES PROTOTYPE IDEAL OCCLUSION

Three factors
1.Occlusal inclined planes of cusps
2.Support given by harmonious size of both arches
3. Influence of muscles
Characteristics of normal occlusion
1. Correct axial position of teeth
2. Normal over jet overbite
3. Normal relationship of individual teeth
4. Normal relationship of dental arches to each
other & to face & cranium

Malocclusion: An arrangement of teeth in a
dentition &/or relation in the jaws to each other
which is not according to the accepted
morphologic configuration of human maxillo-
dentofacial complex.
Classification: it’s a grouping of clinical cases of
similar appearance for ease in comparison ,
handling & discussion

Purposes of classification
• Ease of reference
• Self communication
• For comparison
• For traditional reasons
• Imp tool in diagnosis –treatment planning
In our concept of diagnosis it can be viewed as
orderly reduction of data base to a list of pt s
problems

QUESTIONNAIRE,
INTERVIEW
CLINICAL
EXAMINATION
ANALYSIS OF
DIAGNOSTIC
RECORDS
DATA
BASE
PROBLEM =DIAGNOSIS
LIST
CLASSIFICATION
ORDERLY REDUCTION OF DATABASE TO LIST OF PROBLEMS

WHEN TO CLASSIFY

Malocclusions are morphologic abnormality
morphology
Malocclusions involve 4 tissue systems
Dental dysplasias
Skeletal
Skeletodental

Classification systems
 Angle’s system
Modifications
Lischers modification
Deways modification
 Simons classification
 Ackerman proffit classification
 Malpositions
 Bennet classification
 Skeletal classification
 Modified Angles classification

Angle’s system
E.H Angle -1899
Most uni. Used.
BASIS: Relationship of 1st
per.molar teeth &
alignment of teeth to line of occlusion
Key to occlusion _ max 1st
molar
Basically describes the AP relationship
It has 4 groups
Normal occlusion
Class I malocclusion
Class II malocclusion
Class III malocclusion

Normal occlusion: normal molar relationship , teeth in line of occlusion
Class I normal molar relation but teeth not in line of occlusion
Class II a full premolar width disto-occlusion line of occlusion not specified
Class III a full premolar width mesio-occlusion (resulting in a Class I range of
14 mm)
Class II a full premolar width disto-occlusion and Class III a full premolar width
mesio-occlusion (resulting in a Class I range of 14 mm)
Class I from a full premolar width in either direction to one half of a cusp in
either direction (reducing the range of Class I to 7 mm)

Class I malocclusion
• AP relationship of max & mand molars
correct
• Normal AP relationship between max &
mand
• Usually Normal muscle function
• Bimax protrusion
• Diff between normal occlusion & class I

Class II malocclusion
• Relative MD relations of dental arches -
abnormal with all lower teeth occluding distal to
normal
Molar relation
Consists of 2 divisions
Same molar relation

Class II Div I
Mand denture may r may not be normal with respect to
individual teeh
Protrusion of max incisors
Over eruption of incisors
Narrow max arch V shape
Abnormal muscle function
Lower lip cushions upper teeth
Accentuation of max arch
Depending on tongue lower ant may / may not over erupt
Class II Div I sub division

Typical max incisor inclination in class I , II div I & cl. III

Typical lip postures in cl II div 1

Class II Div 2
Mand molars & mand arch ---post. Position with
respect to max I molars & max arch
Mand arch may or may not show individual
irregularities
An exaggerated COS
Supraversion of incisors
Mand labial gingiva traumatized
Max arch –sometimes wider than normal
Lingual inclination of max centrals , labial
inclination of laterals
Variations

Characteristic milalignments of upper ant teeth in class II div2

Perioral muscle function - normal
Abnormal path of closure due to combination of
lingually inclined max incisors & infraocclusion
of post teeth
Class II Div 2 sub div

Class III malocclusion
• All the lower teeth occlude mesial to normal the
width of 1 bicuspid tooth or more
• mand # large bodily or situated mesially to an
abnormal degree
• Mand incisors in total cross bite
• Lower ant. # excessively inclined lingually# lip
pressure
• Individual tooth irregularities
• Constricted max arch deficient arch length
• Tongue # floor of the mouth
• Max incisors # more lingually inclined
• constricted max archwww.indiandentalacademy.com

Facial profile & molar relationship

Pseudo class III
• Postural , habitual class III
• Lingually inclined max incisors gliding
down lingual surfaces of mand incisors on
closure
• Mand guided ant displacement
• Causes: occlusal prematurities
Premature loss of pri. Posteriors
Enlarged adenoids

Limitations of angle classification
• Discrepancies in vertical & transverse plane
• Inconsistency or gray areas which are not fully
class II or class III
• Cant be applied if I molars are ext’d or missing
• Max molar may vary in AP relationship
• Individual tooth malpositions # overlooked
• Mixed dentition ?
• Malfunctions of muscles & problems of growth of
bones were overlooked
• Etiology ?

Lischers modifications
• Neutrocclusion or class I
• Distocclusion or class II
• Mesiocclusion or class III
Buccocclusion
Linguocclusion
Supraocclusion
Infraocclusion

Some malpositions of individual teeth
“Version” to classify malpositions of teeth in
relation to line of occlusion
Transversion
Linguoversion
Labioversion
Mesioversion
Distoversion
Torsiversion
Axiversion

Deways modification
• Martin Deway
class I 5 types
class III 3 types
Type 1:crowding of max. ant
canines #labio axio or infaversion
Type 2 :max incisors labioversion
Type 3 :max incisors in linguoversion to
mand incisors
Type 4 :molars +/-premolars in
bucco/ linguoversion
Type 5:molars in mesioversion due to shiftingwww.indiandentalacademy.com

Modifications angles class III
Type 1: Individually arches are well formed
Teeth in normal alignment
Edge to edge bite in occlusion
bodily movement of mand arch
Type 2: mand incisors – crowded
lingual relation to max incisors
Type 3 :underdeveloped max arch
crowded max incisors
Cross bite
Well developed mand arch , mand teeth
normally alignedwww.indiandentalacademy.com

Simons classification
• Paul simon
• A 3D classification
• Related denture to face & cranium in 3 planes
1.FH plane vertical relationships
deviations in ht of arch & teeth irt face cranium
2. orbital plane Sagittal deviations in AP relation of
arch , axial inclination of teeth to face & cranium
Law of canine
3. Median Sagittal plane or raphe
for deviations in gen form & width of arches & axial
inclination of teeth irt midline of palate & headwww.indiandentalacademy.com

Deviations
• In Orbital plane
Protractions
Retractions
In FH plane
Attraction
Abstraction
In Mid Sagittal plane
Contractions
Distractions

Demerits
• Cumbersome
• Confusing at times
eg .intrusion of max teeth
extrusion of mand teeth attraction
• Little used

Ackermann proffit system
• 1960 s by informal additions to angles system by
identifying 5 major characteristics
• Overcomes the major weakness of angle system
incorporated evaluation of crowding &
asymmetry
• Recognizes relationship between protrusion &
crowding
• Includes transverse AP vertical planes
• Incorporates information about skeletal jaw
proportions
• Used venn symbolic diagram or set theorywww.indiandentalacademy.com

Set is defined on the basis of morphologic
deviations from ideal
Degree of alignment & symmetry are common to all
dentitions outer envelope /universe [group I]
Profile affected by many malocclusions # major set in
the universe [ group 2]
Deviations in 3 planes of space # represented by 3 to
9 group, which also includes overlapping sub sets

advantages
• Differentiation is made betw. Ske. & dental
problems
• Teaches a perspective about complexities of
malocclusions
• Readily adaptable to compute processing
• Demerits
• etiology ?
• Analysis is static , a functional analysis must still
be made

Bennet ‘s classification
• Based on etiology
• 3 classes
• Class I abnormal position of 1 or more
teeth due to local causes
Class II abnormal formation of part / whole
arch due to developmental defects
Class III abnormal relationship of arches
arch & facial contour
abnormal formation of arch

Skeletal classification
• Class I , class II , class III
• takes relationship of teeth also into consideration
Sk. Class I
• Bones of face & jaws , harmony , & with head
• Profile orthognathic
4 divisions
Div 1. local malrelations of incisors , canine
premolars
Div 2 : max incisor protrusion
Div 3: retroclined max incisors
Div 4: bimax protrusion

Skeletal class 2 :
sub normal distal mand development in relation to
maxilla
Max. arch narrower than mand
Div 1
Crowding in canine region
Cross bite
Vertical ht
Protrusion of max ant teeth
Retrognathic profile
Div 2 : lingual inclined max incisors
laterals normal / labioversion
Sk. Class 3
Overgrowth of mand, obtuse mand plane ang
Prognathic mand www.indiandentalacademy.com

Malpositions
• Individual teeth
• Groups of teeth
• sagittal # labioversion with spacing
without spacing
linguoversion # deep bite , class II div 2
mesioversion , distoversion
• Transverse # buccoversion , linguoversion
crowding ,spacing
• vertical # supraversion infraversion

Transverse occlusal deviations of post. segments

3 categories of crowding [ in mixed dentition ]
I degree crowding
II degree crowding
III degree crowding
On etiology
Primary hereditary
Secondary mesial drift of post teeth
Tertiary assoc with 3 rd molar eruption
By taking inclination of teeth
coronal crowding
apical crowding

Apical base dental arch width
Normal
relationship
Apical
crowding
Coronal crowding

Canine relationships
• Class I The distal surface of the mand canine is
with in 1 premolar’s width of the mesial surface
of max canine
• Class II The distal surface of the mand canine is
distal to the mesial surface of max canine by at
least a width of 1 premolar
• Class III The distal surface of the mand canine
is mesial to the mesial surface of max canine by
atleast a width of 1 premolar

Incisor relationship
• Class I Incisor margins of mand incisors
occlude directly below the middle of the lingual
surfaces of the max incisors
• Class II Incisor margins of mand incisors lie
behind the middle part of lingual surfaces of max
incisors
• Class III Incisor margins of mand incisors lie in
front of the middle part of lingual surfaces of
max incisors

Classification of malocclusion (2)

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