Etiology of malocclusion

ETIOLOGY OF
MALOCCLUSION
GENERAL & LOCAL FACTORS
www.indiandentalacademy.com

The various classification proposed
are:
 White and Gardiner
 Salzmann’s classification
 Moyer’s classification
 Graber’s classification

Graber’s classification
General factors
1. Heredity
2. Congenital
3. Environment
prenatal
postnatal
4. Predisposing
metabolic climatic
and infectious
disease
5. Abnormal
pressure habits
and functional
aberrations—
Thumb sucking,
Tongue thrust,
speech defects etc
6. Dietary problems
7. Posture
8. Trauma and
accidents

Local factors
 1. Anomalies in number of teeth
 2. Anomalies of tooth size
 3. Anomalies of tooth shape
 4. Abnormal labial frenum
 5 Premature loss of deciduous teeth
 6. Prolonged retention of deciduous teeth
 7. Delayed eruption
 8. Abnormal eruptive pathway
 9. Ankylosis
 10.Dental caries
 11.Improper dental restorations

General factors
 Heredity: It includes factors that
result in malocclusion and are
inherited from the parents by the
off springs. These factors can
influence-
 Neuromuscular system
 Dentition
 Skeletal structures
 Soft tissues

Neuromuscular system- There is deformity in
neuromuscular co ordination pattern of
facial,oral and tongue musculature
Dentition- size and shape of the tooth
number of teeth
primary position of tooth germ
shedding of deciduous teeth and
sequence of eruption
mineralization of teeth

 Skeletal structures- underlying basal
bone and other associated cranial bone
structures are partially inherited
Class III skeletal pattern most
commonly show familial tendency
 Soft tisuues (other than neuro muscular)
Size and shape of frenum
Microstomia
Ankyloglossia

Congenital factors
 These malformations are seen at the time of birth
 Mal development of 1st
and 2nd
brachial arches
 Common conditions are:
Micrognathism
Oligodontia
Anodontia
Cleft lip and palate
congenital syphillis
Maternal rubella infections
Cleidocranial dystosis
Cerebral palsy

Micrognathism ( small jaw)
 congenital variety is usually seen with
congenital heart disease and Pierre
Robin syndrome.
 Micrognathia of maxilla is due to
deficiency in the pre maxilla
 Mandibular retrognathism is
characterized by severe retrusion of the
chin

 Oligodontia : different teeth seem
to be affected by different degree
with the third molar being most
affected
 Anodontia absence of teeth
very rare condition
 Cleft lip & palate :generally
associated with under developed
maxilla and related dental
disturbanceswww.indiandentalacademy.com

 Congenital syphills- syphills of
congenital origin is transmitted from the
infected mother to the child:
 Hutchinson’s molar
 Mulberry molar
 Enamel deficiency
 Extensive dental decay
 Small maxilla
 Ant cross bite

 Maternal rubella infections:
dental hypoplasia
retarded eruption of teeth
extensive caries
Cleidocranial dystosis
- unilateral/bilateral partial/ complete absence
of the clavicle
- max retrusion and mandibular protrusion
-over retained deciduous teeth and retarded
eruption of permanent teeth
-presence of supernumerary teeth

 Cerebral palsy
aberrant muscle activity resulting in
malocclusion

Environment
Prenatal factors
• Abnormal fetal posture : -
-Interferes with symmetric
development of face
-Not directly associated with
malocclusion but may be
associated with abnormal pressure
or imbalance.
-Most of the deformities are
temporary and disappears with
time www.indiandentalacademy.com

 Maternal infections such as German
measles and use of certain drugs during
pregnancy like thalidomide can cause
congenital deformities like cleft
 Post natal factors
- Trauma
- Forceps delivery can result in injury to
the TMJ area which can undergo ankylosis
retarded mandibular growth

Predisposing metabolic climate and
disease
Endocrinal imbalance:
Diseases Features
hypopitutarism - delayed tooth
eruption
- incomplete root
formation
Hyperpitutarism -large mandible
-enlarged tongue
- accelerated
dental development

 Hypothyroidism - Growth
retardation
- Delayed
eruption of the
teeth
- Maxillary
protrusion
- Spacing
 Hyperthyroidism - Accelerated
skeletal
growth
- Irregular eruption
of the teeth
-Mild prognathism

 Hypoparathyroidism - retarded
eruption
-early exfoliation
-enamel defects
 Hyperparathyroidism - demineralization
-disappearance of
lamina dura
-mobility of teeth

Metabolic disturbances
 Acute febrile diseases may also
affect the dentition and its
surrounding hard and soft tissue.
 If severity and duration is not
prolonged the child is able to
recoup and catch up growth is
possible

Infectious diesease
 Bacterial infection
 Osteomyelitis - Bone response to
force is altered
 Congenital syphillis
–under developed maxilla
- narrow maxillary arch
- enamel hypoplasia
-Defect in shape of teeth

 Viral infection
 Mumps -dental hypoplasia
-retarded eruption
-extensive caries
-Inflammation/
congestion of gingiva
 Measles -airway obstruction
 Rubella -retarded eruption of
teeth
-congenital
malformations
including cleft lip and
palate

Dietary problems
 Protein deficiency - delayed eruption
 Vitamin A deficiency -calcification of teeth
is affected
- retarded eruption
 Vitamin B complex - cheilosis
- retarded growth
- pernicious anaemia

 Vitamin C deficiency - disturbed
collagen fibre
formation
- bleeding gums
- loosening of teeth
 Vitamin D -disturbed
calcification of
teeth
-poor quality of
teeth
- narrow maxillary arch
- High palatal vault
-Under developed mandible

 Hypervitaminosis D - poorly calcified
teeth
-decalcification of
bones
-Increased
osteoclastic
activity

Abnormal pressure habits and
functional aberrations
 Thumb sucking
 Tongue thrust
 Lip and nail biting
 Abnormal swallowing habits
 Speech defects
 Respiratory abnormalities
 Tonsils and adenoids
 Pshychogenic habits and bruxism

 All these habits are functional
aberrations which produces forces that
are abnormal and these forces are
capable of bringing about a permanent
deformity in the developing musculo
skeletal unit
 Deformity depends upon the-
- Intensity
- Duration
- Frequency

Posture
 Poor postural habit
 It may be associated with
maloclusion though not proved

Accidents and Traumas
 Injuries of the dento alveolar region
may get unnoticed during the early
years of life
 Responsible for
- Non vital teeth
- Ankylosed teeth
- Injuries at condylar region

Local factors—anomalies in number
 Supernumerary teeth
–Teeth extra to normal complement
-Most common mesiodens
-may closely resemble the teeth of the
group they belong or bear no resemble
supplemental teeth- teeth that bear close
resemble to a particular group of teeth
and erupt close to original site of these
teeth
 Most common are-premolar region or the
lat regionwww.indiandentalacademy.com

supplemental teeth-
-Teeth bear close resemble to a
particular group of teeth
- Erupt close to original site of these
teeth
-Most common are-premolar region
or the lateral incisor region

 Supernumerary teeth can cause-
-Non eruption of adjacent teeth
-Delay the eruption of adjacent teeth
-Deflect the erupting tooth into abnormal
locations
-Crowding

 Missing teeth
–more common condition than
supernumerary teeth
Oligodontia- absence of many teeth
Anodontia-absence of all the teeth
Hypodontia-presence of few teeth
eg-hypo hydrotic ectodermal
dysplasia

 This condition can lead to
- Spacing between the teeth
- Aberrant swallowing patterns
-Abnormal axial inclination of adjacent
teeth

Anomalies of tooth size
 Microdontia- True generalized
form of microdontia is rare
 Usually seen in cases of pitutary
dwarfism
 Most common form of localized
microdontia is- max lat incisors
called-peg lateral

Anomalies of tooth shape-
 Fusion
- tooth arises through the union of two
normally seperated tooth bud
-may lead to spacing
 Gemination
 Twinning
 Concrescence
 Dilaceration

Abnormal of labial frenum
 - Often associated with maxillary mid
line spacing
 A heavy fibrous frenum is found
attached to inter dental papilla
 Can prevent the two max central incisors
from approximating each other

 Blanch test- is used to determine the
role of frenum as a casuative factor for
mid line test
 Step 1. The lip is pulled superiorly and
anteriorly
 Step 2. Any blanching indicates fibres of
the frenum crossing the alveolar ridge
 An IOPA will show notching in the inter
dental alveolar ridge region

Premature loss of deciduous teeth-
-
-Decrease in
total arch length
as the posterior
teeth move
mesially
-Ectopic eruption
of teeth
-Shift in the midline

Prolonged retention of deciduous teeth
 Reasons for prolonged retention of
tooth are-
- Absence of any underlying
permanent teeth
- Endocrinal disturbances-
Hypothyroidism
- Ankylosed deciduous teeth
- Non vital teeth that do not resorb

 Prolonged
retention of
deciduous teeth
result in lingual or
palatal eruption of
their successors.

Delayed eruption of permanent teeth
 May result in ectopic eruption of
permanent teeth
 The reasons for delayed eruption
are-
-Congenital absence of the
permanent tooth
-Presence of supernumerary teeth

-Presence of heavy mucosal barrier
can prevent the permanent tooth
from emerging into the oral cavity
- Presence of deciduous root fragments
- Endocrinal disturbances
- Ankylosed teeth

Abnormal eruptive path
 Causes for this are:
- Tooth bud displaced from its ideal
position
- Presence of supernumerary teeth ,
odontomas, retained tooth may
divert a tooth from its eruptive
path

 Retained deciduous teeth might force a
tooth to erupt along a path of least
resistance rather than in place of
deciduous teeth
 Arch length deficiency or excess of tooth
material may cause one or more teeth to
deviate from their eruptive path
- Most common is max canine

 Various reasons for this behavior are-
-Travels the longest distance, from near the
floor of the orbit to cover the arch
- It is the last anterior tooth to erupt and
loss in arch length- anterior or posterior
teeth may impinge on the space required
for it to erupt
- Abnormal position of the tooth bud

Ankylosis
-Union of the root or part of a root
directly to the bone without the
intervening periodontal ligament
-Associated with certain infections,
endocrine disorders, and congenital
diseases

Dental caries
-Proximal caries may result in
reduction of arch length
-Loss of E space
-Migration/ tilting of teeth in the
space available
-Supra eruption of the teeth in
opposing arch

Malocclusions caused due to caries

Improper dental restoration
-Under contoured proximal restoration- decrease
in arch length
-Over contoured restoration- may bulge into the
space to be occupied by the succadenous tooth
-Overhang or poor proximal contact- periodontal
breakdown
-Occlusal prematurities due to over contoured
occlusal restoration can cause a functional shift
of the mandible

Etiology of malocclusion

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