Classification of malocclusion1

CLASSIFICATION OFCLASSIFICATION OF
MALOCCLUSIONMALOCCLUSION
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Outline
 Introduction
 Purpose and need for classification
 Classification systems:
1.Angle’ classification
2.Modifications of Angle’s classification
3.Moyer’s etiological classification
4.Simon system
5.Ackerman-Proffit system
6.Salzmann’s classification
7.British standard Incisor classification
8.Bennet’s classification
 Conclusion

Introduction
 Orthodontics -“Science of Infinite
Variations” -Jackson
 Occlusion – “Normal relation of occlusal
inclined planes of the teeth when the jaws are
closed” -E.H.Angle
 Malocclusion – Any deviation from the normal
or ideal occlusion.
-Glossary of Orthodontic terms

What is a classification system?
 A classification system is a grouping of clinical
cases of similar appearance for ease in
comparison, handling and discussion;
 it is not a system of diagnosis, method for
determining prognosis, or a way of defining
treatment.

Purpose of classifying
 Conceptually, Classification can be viewed as an
orderly way to derive a list of the patient’s
problems from the database.

Classification is needed for
 Ease of reference
 Comparison
 Communication

Malocclusions can be broadly
categorized into-
 Dental dysplasias
 Skeletal dysplasias
 Skeletodental dysplasias

Angle’s Classification
 Introduced by Edward
H.Angle in 1899.
 First and most important
universally used
classification.
E.H.Angle
Father of Modern
Orthodontics

Principles of Angle’s classification-
 Maxillary first permanent molar- “key to
occlusion”
 Relationship of first molars
 Line of occlusion (Caternary curve)
 Anteroposterior relationship of dental
arches.

Angle’s Classification has four
classes
 Normal occlusion
 Class I (neutroclusion)
 Class II (distoclusion)
 Class III (mesioclusion)

Normal occlusion
 Angle’s concept of Normal occlusion is
essentially the description of an ideal occlusion.
 Normal molar relationship.
 Line of occlusion. (caternary curve)
 Normal anteroposterior relationship between
maxillary and mandibular dental arches.

Normal Class I molar relationship:
1.The mesiobuccal cusp of the mandibular first1.The mesiobuccal cusp of the mandibular first
molar occludes in the embrasure area between themolar occludes in the embrasure area between the
maxillary second premolar and first molar.maxillary second premolar and first molar.
2.The mesiobuccal cusp2.The mesiobuccal cusp
of the maxillary first molarof the maxillary first molar
is aligned directly over theis aligned directly over the
buccal groove of thebuccal groove of the
mandibular first molar.mandibular first molar.
3.The ML cusp of the maxillary first molar is3.The ML cusp of the maxillary first molar is
situated in the central fossa area of mandibular firstsituated in the central fossa area of mandibular first
molar.molar.

Line of occlusion (catenary curve)
Line of occlusionLine of occlusion is ais a
smooth curve passingsmooth curve passing
through the central fossa ofthrough the central fossa of
each upper molar and acrosseach upper molar and across
the cingulum of the upperthe cingulum of the upper
canine and incisor teeth. Thecanine and incisor teeth. The
same line runs along thesame line runs along the
buccal cusps and incisalbuccal cusps and incisal
edges of the lower teeth.edges of the lower teeth.

In original classification by Angle-
 All teeth except lower centrals and upper third
molars have two antagonists.
 Also the upper first molar has a mesial tilt that
allows the distal incline of distal cusp of upper
first molar to occlude with mesial incline of
mesial cusp of the lower second molar. (Angle, later
Strang, Stoller and Andrews)

Angle’s Class I Malocclusion:
 Normal anteroposterior
relationship between maxilla and
mandible.
 Normal class I molar relation.
 Normal muscle function.
 Line of occlusion is incorrect
because of malposed teeth,
rotations or other causes.

Bimaxillary protrusion
 Occasionally, with
normal anteroposterior
jaw relationship, the
teeth are forward on their
respective bases termed
as Bimaxillary
protrusion.
 Angle considered
Bimaxillary protrusions
in class I category.

Angle’s class I is a range, rather than
an ideal point…….!
 In 1900, Angle made class II a full premolar-
width distocclusion and class III a full premolar-
width mesiocclusion, resulting in a class I range
of 14 mm(7+7).

In 1907, Angle revised definition of 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(3.5+3.5).
This refinement brought more malocclusions into
the class II and class III categories.

Angle’s Class II Malocclusion:
 Lower dental arch is in a DISTAL relation to the
upper dental arch.
 Class II molar relation.
 Line of occlusion not specified.
 There are 2 divisions in class II malocclusions

Class II molar relation:
 The mesiobuccal cusp of the mandibular first
molar occludes in the central fossa area of the
maxillary first molar.
 The mesiobuccal cusp of
the mandibular first molar
is aligned with the buccal
groove of the maxillary
first molar.
 The DL cusp of the maxillary first molar occludes
in the central fossa area of the mandibular first
molar.

Division 1
 Proclined upper incisors.
 ‘V’ shaped maxillary arch.
 Supraversion of the lower
anteriors.
 Abnormal muscle activity.

Division 2
 Lingually inclined upper centrals
and labially tipped upper lateral
incisors.
 Wide maxillary arch.
 Exaggerated curve of spee.
 Closed bite.

Division 2 (contd.)
 Supraversion of mandibular
incisors.
 Perioral musculature usually
normal.
 Excessive interocclusal
clearance.
 Forced retrusion of the
mandible.

Class II subdivision
 When the class II molar relationship occurs on
one side of the dental arch only, the
malocclusion is referred to as a subdivision of
its division.
It can be-
 Class II div.1 subdivision
 Class II div.2 subdivision

Subdivision…….??
Refers to which side(class II or class I)?
 Majority – Subdivision refers to Class II side.
(AAO glossary, moyers, proffit, salzman….)
 The most accurate depiction would be to specify
which side is class II and which is class I.
e.g Class II div 1, Subdivision; R class II, L class I.
Siegel, M.A. : A matter of Class: Interpreting
subdivision in a malocclusion. AJO 2002;122;582-6.

Angle’s Class III Malocclusion
 Mandibular dental arch in MESIAL relation to
the maxillary dental arch.
 Class III molar relation.
 Line of occlusion not
specified.

Class III molar relation:
 The distobuccal cusp of the mandibular first
molar is situated in the embrasure between the
maxillary second premolar and first molar.
 The MB cusp of the
maxillary first molar is
situated over the
embrasure between the
mandibular first and
second molar.
 The ML cusp of the maxillary first molar is
situated in the mesial pit of the mandibular
second molar.

Class III (contd.)
 Mandibular incisors – cross bite, inclined
lingually.
 Maxillary arch constricted.

Pseudo Class III
 This is not a true class III malocclusion but the
presentation is similar. Here the mandible shifts
anteriorly in the glenoid fossa due to a premature
contact of the teeth or some other reason when
jaws are brought together in centric occlusion.
 Lingually inclined maxillary incisors leads to
anterior displacement of the mandible.
 Can be due to premature loss of deciduous
posteriors.
 It can also be due to occlusal prematurities or
enlarged adenoids.

Class III subdivision
 Class III molar relation on one side & Class I
on the other.

Advantages
 Simplicity.
 It is the most traditional, most practical and
Universally accepted method of classification.
 It was the first to define normal occlusion in
natural dentition.
 Foundation for future classifications.

Disadvantages of Angle’s
Classification
 Considered Anteroposterior relationship, not
vertical & transverse.
 First permanent molars are not fixed
points.
 Cannot be applied if first molars missing.
 Cannot be applied to deciduous dentition.
 No differentiation between skeletal & dental
malocclusion.
 Classification does not highlight etiology.

Martin Dewey’s modification of
Angle’s Malocclusion(1915)
Dewey modified Class I malocclusion
with-
Type I: Crowded anterior teeth.
Type II: Protrusive maxillary incisors.
Type III: Anterior crossbite.
Type IV: Posterior crossbite.
Type V: Mesial drifting of permanent molar.

Type I: Crowded anterior teeth.
Type II: Protrusive maxillary incisors.

Type III: Anterior crossbite.
Type IV: Posterior crossbite.

Type V: Mesial drifting of permanent molar.

Dewey modified class III malocclusion
with-
 Type 1: Viewed separately, archs are normal, In
occlusion – edge to edge incisor alignment
suggestive of forwardly moved mandibular arch.

Type 2: Crowding and lingual relation of
mandibular incisors to maxillary incisors.

Type 3: Crowding and cross bite relation of
maxillary incisors to mandibular incisors.

Lischer’s modification of Angle’s
Classification(1933)
 Lischer substituted Angle’s classes by-
 “Neutrocclusion” - Angle’s class I
 “Distocclusion” - Angle’s class II
 “Mesiocclusion” - Angle’s class III

In addition, Lischer described nomenclature for
individual tooth malpositions by adding suffix
“version” to a word indicating deviation from
normal position
1.Mesioversion:
2.Distoversion:

3.Lingoversion:
4.Labioversion

5.Infraversion:
6.Supraversion:

7.Axioversion:
8.Transversion:

9.Torsiversion:
(rotation)
Mesiolingual
or distolabial
rotation
Mesiolabial or
distolingual
rotation

Van der Linden classification of Class
II Div 2
Depending on the spatial conditions in the
maxillary dental arch.
Type A- The upper central and lateral
incisors are retroclined.
It is of less severe in nature.

Type B- The central incisors
are retroclined and overlapped
by the lateral incisors.
Type C- The central and
lateral incisors are retroclined
and overlapped by the
canines.

A MODIFIED ANGLE
CLASSIFICATION
A goal-directed classification
 Angle in his classification of malocclusions,
appears to have made class I a range of
abnormality, not a point of ideal occlusion.
 Current goals of orthodontic treatment however,
strive for the designation “class I occlusion” to be
synonymous with the point of ideal intermeshing
and not a broad range.
(Morton I. Katz, AJO,1992)

 If contemporary orthodontists are to continue to
use class I as a goal, then it is appropriate that
angle’s century old classification, be modified to
be more precise.
 In this modification, angle’s prototype ideal
occlusion has been retained.
 The larger 7 mm range of class I has been
discarded.

Premolar derived Classification
 Class I : The most anterior upper premolar fits
exactly into the embrasure created by the distal
contact of the most anterior lower premolar.
 When this relationship is achieved, the canines
will also relate correctly, as will the incisors.
 But, molar relation is not considered.

Modified class I
Traditional angle’s class II
Modified class I
Traditional angle’s class III

Deciduous and mixed dentition
classification
 Class I : The center axis of the upper first
deciduous molar should split the embrasure
between both lower deciduous molars.
 If upper first deciduous molar is lost permaturely
lost, a line drawn through the center axis of the
edentulous space should bisect the embrasure
between the two lower deciduous molars.

Quantifying the classification:
Modified classification designates-
 Ideal cusp-embrasure occlusion (0)
(as described by angle)
 Class II (+)
 Class III (-)
 Right side is evaluated first, then the left side.
 Ideal occlusion on both sides (0,0)

Ideal relation on right, 2mm class II tendency on left side = (0, +2)
Half cusp class II on right side, full cusp class II on left side = (+4,+8)

1.5mm class II on right side, 3.5mm class III on left side = (+1.5,-3.5)
Note traditional angle can not classify a patient with both class II and
class III sides.

Advantages:
 This new system establishes a treatment goal that
is a specific cusp-embrasure point rather than a
range.
 Quantifies the degree of occlusal error of a
malocclusion precisely in mm and for each side
separately.
 Covers even the rare malocclusions. (class II on
one side and class III on other side)
 Classifies deciduous and mixed dentition.
 Can be computerized.

Disadvantages
 Does not consider malocclusions in transverse
and vertical planes.
 Does not consider etiology.
 Doesn't include dental or skeletal malocclusion.

Moyer’s Etiologic Classification
Classification based on tissue origin-
–Osseous
Problems in growth, size, shape or proportions of
the bones are considered.
Orthodontic problem results when the bones of the
craniofacial complex develop in an abnormal
manner.
‘Basal bone/Apical bone’ are the main areas
involved in osseous dysplasias.

 It should be noted that other parts always are
affected secondarily.
 Malocclusion of teeth in these cases are an
expression or symptom of the principle fault.
 Cephalometric analysis provides best means of
studying these variations.
 Treatment is to correct the osseous dysplasia

Muscular
Malfunction of dentofacial musculature.
Any persistant alteration in the normal synchrony
of the mandibular movements or muscle
contractions may result in distorted growth of
facial bones and abnormal positions of teeth.
Most of these neuromuscular pattern of behavior
are habits. They were once learned and hence can
be altered.
In case of skeletal manifestations – Not easily
reversible.

This category includes :-
 Functional “slides into occlusion” due to occlusal
interferences.
 Detrimental sucking habits (e.g., thumb, finger,
lip, etc…)
 Abnormal patterns of mandibular closure.
 Incompetent normal reflexes. (e.g., lip posture)
 Abnormal muscular contractions (e.g., tongue-
thrusting during swallowing, mouth breathing)
Treatment of original reflexes or habit if detected
early – easy.

Dental
1. Dental problems primarily involve the teeth &
supporting structures.
2. Precise dental abnormality to be determined.
3. Care must be taken to determine whether the
dental abnormality is the primary problem or
whether it is secondary to aberrations in
osseous growth or malfunction of muscles.

This category includes –
 Malpositions of teeth.
 Abnormal number of teeth.
 Abnormal size of teeth.
 Abnormal conformation/texture of teeth.

 Although all three tissues (bone, muscle, teeth)
usually are involve in all dentofacial deformities,
one is dominant – one is most likely the primary
etiologic tissue site.
 Primary etiological tissue needs to be identified
to determine the final treatment plan and
prognosis.

References:
 Robert E. Moyers- Handbook of Orthodontics- 4th
ed
 William R. Proffit- Contemporary Orthodontics- 3rd
ed
 T. M. Graber- Orthodontics- Principles and practice
 Graber T.M, Vanarsdall R.L –Orthodontics-current
principles and techniques-3rd
ed
 T. C. White, J. H. Gardiner, B. C. Leighton-
Orthodontics for dental students.
 Samir E.Bishara- Text book of Orthodontics- 3rd
ed
 Rakosi T, Joans I, Graber T.M – Orthodontic-
Diagnosis – 1st
ed
 Van der Linden- Development of the dentition.
 Daskalogiannakis J- Glossary of orthodontic terms.

 Katz M.I- Angle classification revisited 1: Is current use
reliable? AJO 1992;102;173-9.
 Katz M.I- Angle classification revisited 2: A modified
angle classification. AJO 1992;102;277-84.
 Siegel, M.A. : A matter of Class: Interpreting subdivision
in a malocclusion. AJO 2002;122;582-6.
 Brin I, Weinberger T, Ben-chorin E- Classification of
occlusion reconsidered. EJO 21(1991)169-174.
 James c. Ackerman, Williams R. Proffit- The
characteristics of malocclusion: A modern approach to
classification and diagnosis. Am J Orthod. 1969; vol-56,
no-5.

Classification of malocclusion1

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