1. Etiology Of malocclusion
Presented By:
Ritu Agrawal
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2. Definition of Malocclusion
Malocclusion is defined as a defect in the
normal position of the upper and lower
teeth when the mouth is closed, as from
abnormal development of the jaw
or
Misalignment between the upper and lower
teeth when the jaw is closed, resulting in a
faulty bite
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3. Classification of etiologic
factors of malocclusion
1.
Moyer’s classification
2.
White &Gardiner’s classification
3.
Graber’s classification
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4. Moyer’s classification of
etiology
1. Heredity
• Neuromuscular system
• Bone , teeth
• Soft part [other than nerves & muscles]
2.Developmental defects of unknown origin
3.Trauma
• Prenatal trauma& birth injuries
• Post natal trauma
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5. 4. Physical agents
i. Nature of the food
ii. Premature extraction of primary teeth
5. Habits
i. thumb sucking, lip sucking
ii. tongue thrusting
iii. posture
iv. Nail biting and other habits
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6. 6.Diseases
i. Systemic diseases
ii. Endocrine disorders
iii. Local diseases
iv. Nasopharyngeal diseases and disturbed
respiratory function
v. Gingival and periodontal diseases
vi. Tumour
vii.caries
7. Malnutrition
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7. White & Gardiner’s
Classification
1. Dental base abnormalities
i. Antero- posterior malrelationship
ii. Vertical malrelationship
iii. Lateral malrelationship
iv. Disproportion of size between teeth & basal
bone
v. Congenital abnormalities
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8. 2. Pre eruption abnormalities
i.
ii.
iii.
iv.
v.
vi.
Abnormalities in position of developing tooth
germ
Missing teeth
Supernumerary teeth & teeth in abnormal
form
Prolonged retention of deciduous teeth
Large labial frenum
Traumatic injury
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9. 3. Post- eruption abnormalities
 Muscular
- active muscle force
-Rest position of musculature
-Sucking habits
-Abnormalities in path of closure
 Premature loss of deciduous teeth
 Extraction of permanent teeth
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10. Graber’s classification
GENERAL FACTORS:
1. Heredity
2. Congenital
3. Environment
 Prenatal[ trauma, German measles,maternal
diet]
 Post natal[ birth injury, cerebral palsy, TMJ
injury]
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11. 4. Pre disposing metabolic climate & disease
 Endocrine imbalance
 Metabolic disturbances

Infectious diseases
5. Dietary problems [nutritional deficiency]
6. Abnormal pressure habits & functional
aberrrations
 Abnormal sucking
 Tongue thrust & tongue sucking
 Lip and nail biting
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12.  Abnormal swallowing habits
 Speech defects
 Respiratory abnormalities[ mouth breathing etc]
 Tonsils & adenoids[compensatory tongue
position]
 Psychogenic tics & bruxism
7. Posture
8. Trauma & accidents
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13. LOCAL FACTORS:
1. Anomalies of number
 supernumerary and missing teeth
2. Anomalies of tooth size
3. Anomalies of tooth shape
4.Abnormal labial freenum[ mucosal barrier]
5.Premature loss of deciduous teeth
6.Prolonged retention of deciduous teeth
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14. 7. Delayed eruption of permanent teeth
8. Abnormal eruptive path
9. Ankylosis
10. Dental caries
11. Improper dental restorations
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15. GENERAL FACTORS
1. Heredity
Hereditary causes of malocclusion include all
factors that are inherited from parents by the
offspring
There are no of traits that are influenced by the
genes that include
a. Tooth size - eg.. microdontia , macrodontia
b. Arch dimensions
c. crowding
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16. d. Abnormalities of tooth shape –
eg….
Peg shaped laterals
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17. e. Abnormalities of tooth number eg… anodontia,
hypodontia , oligodontia
f. Interarch variations
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18. g.Frenum - include size and shape of the frenum
and specially maxillary labial frenum is said to
be genetically influenced . for eg …. Midline
diastema
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19. 2. Congenital factors
These defects include malformations
that are seen at the time of birth .It can be
broadly classified as general and local
…..
General factors are –
a . Malnutrition
b. Endocrinopathies
c. Infectious diseases
d.Accidents during pregnancy and
birth
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20. Local factors area. Cleft lip and palate
b. Micro and macroglossia
c.Cleidocranial dysostosis
3.Enviornmental factors- include
Prenatal factors

Abnormal foetal posture during
gestation can interfere with the symmetric
development of face
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21. others are maternal fibroids, amniotic lesions
,maternal diet ,infection such as german measles etc
Postnatal factors - include
i.
Forceps delivery which can result in
injury to tmj and can cause ankylosis ,retarded
mandibular growth
ii.Cerebral palsy , traumatic injuries etc can also
cause growth retardation resulting in facial
asymmetry
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22. 4.Pre disposing metabolic climate and disease
a. Endocrine imbalance - some disturbances are
Disease
 Hypothyroidsm
Features
retarded growth
retained deciduous tooth
delayed tooth eruption
abnormal root resorption
irregularites in tooth
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23. Hyperthyroidism
Hypoparathyroidism
Accelerated skeletal growth
increase in metabolic rate
Premature eruption of dec
teeth
osteoporosis ,
open bite tendency
changes in Ca metabolism
delayed tooth eruption
early exfoliation
enamel defects
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24.  Hyperparathyroidism
increase in blood Ca
demineralization
mobility of teeth due
to loss of cortical
bone and resorption
of alveolar process
b.Metabolic disturbancesAcute febrile disease slow down the pace of growth
and development and may cause disturbance in tooth
eruption and shedding increasing risk of malocclusion
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25. c. Infectious diseases- for eg…
 Congenital syphillis - transmitted by infected
mother to child ,has following features
peg shaped lateral incisors
mulberry molars
enamel hypoplasia
dental decay ,narrow max
arch ,anterior cross bite
depressesd nasal bridge
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26. Maternal infection like rubella,rubeola and
cytomegalo viruses causes developmental defects like
cleft lip and cleft palate
5.Nutritional deficiency
During growth this may results in abnormal
development
Vitamin deficiency states like rickets, scurvy and
beriberi predisposes to the development of
malocclusion
Deficiency of calcium can upsets the development of
teeth
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27. Abnormal pressure habits and functional
aberrations
Thumb sucking
Tongue
thrusting
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28. Local factors
a)Anomalies in number of teeth
The anomalies in the no of teeth can be of two
types –
1. supernumerary – teeth that are extra to the
normal complement are supernumerary , they
may or may not bear resemblance to the adjacent
teeth
 for eg… distomolars , paramolars
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29. Most common is mesiodens
These teeth may cause –
 Non eruption of adjacent teeth
 delay the eruption of adjacent teeth
Crowding in dental arch
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30. 2. Missing
teeth- congenital missing teeth
are more common than supernumerary
teeth
 hypodontia ,anodontia ,oligodontia are
eg of congenital missing teeth.
Most common missing teeth are third
molars , max lateral incisors .
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31. Bilateral missing lateral incisors
It can lead to –
Gaps between teeth
Abnormal tilting of adjacent teeth
 Aberrant swallowing pattern
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32. b.Anomalies of tooth shape –
anomalies of tooth shape include fusion,
gemination concrescence, talons cusp
etc
 Congenital syphilis is often associated
with the presence of peg shaped
laterals
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33. c.Premature loss of deciduous teethEarly loss of deciduous teeth can cause
migration of adjacent teeth into the space and
can prevent eruption of permanent successor
In case of anteriors -spacing occur between
the erupted anterior teeth – shift in midline
Loss of deciduous second molar –mesial
migration of 1st permanent molar –loss in the
arch length
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34. d.Prolonged retention of deciduous teeth
Retention of deciduous teeth beyond the
usual eruption age of their permanent
succesors may cause
• buccal /labial or palatal/lingual deflection
in its path of eruption OR
• Impaction of the permanent tooth
Reasons for retention are
i. absence of underlying permanent teeth
ii.Endocrinal disturbances
iii. ankylosed deciduous teeth fail to resorb
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35. Labially erupting max canine due to
retained deciduous canine
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36. e. Delayed eruption of permanent teeth
Reasons are
i. congenital absence of the permanent tooth
ii. presence of supernumerary tooth
iii.Premature loss of deciduous tooth
iv. endocrinal disorders
v.Early loss of adjacent teeth or spacing
between erupted permanent teeth
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37. f. Ankylosis
It is a condition wherein a part or whole of the
root surface is directly fused to the bone with
the absence of the intervening periodontal
membrane
More commonly associated with the certain
infections , endocrinal disorders ,congenital
disorder
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38. g. Dental caries and improper dental
restorations
Caries can lead to premature loss of
deciduous or pmt teeth –migration of
adjacent teeth-supraeruption of opposing
teeth
 proximal caries – reduction of arch length
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39. Improper dental restorationsOver contoured occlusal restoration
-premature contacts - functional shift of
mandible
Under contoured occlusal restoration-supra
eruption of the opposing teeth
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40. Thank you
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