This document discusses the etiology and classification of malocclusion. It identifies several local and general factors that can cause malocclusion, including heredity, congenital defects, environmental factors like thumb sucking and tongue thrusting, metabolic diseases, accidents or trauma, anomalies in tooth number or size, and abnormal frenum or dental restorations. It provides examples for each factor and their effects on dental alignment. Congenital defects discussed in detail include clefts of the lip and palate, congenital syphilis, and macro/microglossia.

1. NAME:DHVANI DESAI
ROLL NO:70

2. Malocclusion
defined as a condition in which there is deflection
from the normal relation of the teeth to other
teeth in the same dental arch or teeth in opposing
arch.

3. • Etiology of malocclusion is the study of its causes.
• Recognition and elimination of the etiological
factors is important so that one can prevent and
correct the malocclusion and obtain a permanent
result.

4. heredity
congenital
environment
Pre disposing metabolic climate & disease
Dietary problems
Abnormal pressure habits &functional
aberrations.
posture
Trauma & accidents
General factors
Graber’s classification

5. Anomalies of number
Anomalies of tooth size
Anomalies of tooth shape
Abnormal labial frenum
Premature loss of deciduous teeth
Prolonged retention of deciduous teeth
Delayed eruption of permanent teeth
Abnormal eruptive path
ankylosis
Dental caries
Improper dental restorations
Local factors

6. Heredity

7. • It has for long been attributed as one of causes of
maloccclusion.
• Child is a product of parents who have dissimilar
genetic material.
• The child may inherit conflicting traits from both
the parents resulting in abnormalities of the
dentofacial region.
• According to Lundstrom there exist a number of
human trait that are influenced by the genes that
include:

8. Tooth size
Crowding/spacing
Arch dimension
Abnormalities of tooth number
Abnormalities of tooth shape
Over jet
Inter arch variation
Frenum

9. • Crowding/spacing:
Spacing
Crowding

10. ❑ Congenital defects
• Congenital defects or development defects are
malformations seen at time of birth.
• Caused by variety of factors including
genetic,radiologic,chemical,endocrine,infection
and mechanical factors.

11. Clefts of the face and palate
Macro and microglossia
Clediocranial dysostosis
Congenital syphillis
Maternal rubella infection
Cerebral palsy

12. CLEFTS OF THE LIP AND PALATE

13. • Clefts involving the lip and palate are the most
commonly seen development defects that occur
as a result of non-fusion between the various
embryonic processes.
• Cleft patients may exhibit a number of dental
problem including
• missing teeth
• mobile teeth
• Rotations
• crossbite etc.

14. CONGENITAL SYPHILLIS
• Syphilis of congenital origin is transmitted from
the infected mother to the child.
• The child exhibits one or more of the following
features:

15. • Hutchinson’s incisors

16. • Mulberry molars

17. • Enamel deficiencies

18. • Extensive dental decay

19. • Anterior crossbite

20. MATERNAL RUBELLA INFECTION
• Maternal rubella infection during pregnancy
believed to cause widespread congenital
malformation in the child because growth rate
of fetal cells are reduced.
• The following are some of the features that can
be seen:
• Dental hypoplasia
• Retarded eruption of teeth
• extensive caries.

21. MACRO AND MICROGLOSSIA

22. • Cledocranial dysostosis
• This is a congenital condition
characterized by unilateral or
bilateral,partial or complete
absence of the clavicle.
• The patient may exhibit the
following features:
• Maxillary retrusion and possible
mandibular protrusion
• Over retained deciduous teeth
and retarded eruption of
permanent teeth
• Presence of supernumerary teeth
• Presence of short and thin roots.

23. CEREBRAL PALSY
• This is a condition where
in the patient lacks
muscular co-ordination
• It usually occurs due to
birth injury.
• uncontrolled and
aberrant muscle activity
upset the muscle the
balance resulting in
malocclusion.

24. ❑ENVIRONMENT
• Various prenatal and postnatal evironmental
factors can cause malocclusion:

25. • PRENATAL FACTORS:
• The foetus is well protected against injuries
and nutritional deficiencies during pregnancy
but there are certain factor the pesence of
which can result in abnormal growth of the oro-
facial region thereby predisposing to
malocclusion.
• Abnormal fetal posture during gestastion is said
to interfere with symmetric development of the
face.

26. • Maternal infection such as german measles and
use of certain drugs during pregnancy such as
thalidomide can cause gross congenital
deformities including clefts.

27. • POSTNATAL FACTORS
• Forceps delivery can result in injury to the tmj
area,which can undergo ankylosis.such patients
show retarted mandibular growth and thus have a
hypoplastic mandible.
• Traumatic injuries that cause condylar fracture can
cause growth retardation resulting in marked facial
asymmetry.

28. Endocranial imbalance
Hypothyrodism
Hypoparathyrodism
Hyperthyrodism
hyperparathyrodism
❑PREDISPOSING METABOLIC, CLIMATE AND DISEASE
Number of endocranial disorders,infectious condiions and metabolic
disturbances can predispose to malocclusion

29. • Hypothyrodism
• Retardation in rate of calcium deposition in
bones and teeth.
• Marked delayed in tooth bud formation and
eruption of teeth.
• Deciduous teeth are often over retained and
permanent teeth are slow to erupt.
• Abnormal root resorption.
• Irregularities in tooth arrangement and
crowding of teeth can occur.

30. • Hyperthyrodism
• This condition is characterized by increase in
the rate of maturation and increase in
metabolic rate.
• The patient exhibits premature eruption of
deciduous teeth,disturbed root resorption of
primary teeth and early eruption of permanent
teeth.
• The patient may have osteoporosis which
contraindicates orthodontic treatment.

31. • Hypoparathyrodism ;
• Associated with changes in calcium metabolism.
• Can cause delayed eruption of deciduous and
permanent teeth,altered tooth morphology and
hypoplastic teeth.

32. • HYPERPARATHYRODISM:
• It produces increases in blood calcium.
• There is a demineralisation of bone and disruption
of trabecular pattern.
• Teeth may become mobile due to loss of cortical
bone and resorption of the alveolar process.

33. Hypopitutarism:
• Retarded growth.
• Delayed tooth eruption
• Incomplete root formation
with incomplete closure of
apical foramen.

34. • HYPERPITUTARISM:
• Accelerated
development seen
especially of the
mandible.
• Accelerated dental
development and
eruption.
• Thickening of
cortical bones.

35. METABOLIC DISTURBANCES:
• Acute febrile disease are believed to slow down
the pace of growth and development.
• This condition may cause a disturbance in tooth
eruption and shedding thereby increasing the risk
of malocclusion.

36. Infectious disease
 Osteomyelitis
 mumps

37. Osteomyelitis
• Bone response to force is altered

38. Mumps
• Rapid enlargement of salivary gland.
• Dental hypoplasia
• Delayed eruption.

39. • Nutritional imbalance
Nutritional imbalance Clinical features
Hypervitaminosis A Cleft lip and cleft palate
Riboflavin deficiency Cleft lip and cleft palate
Folic acid deficiency Cleft lip and cleft palate
Mental retardation
insulin deficiency Cleft lip and cleft palate
Iodine deficiency cretinism

40. Nutritional imbalance Clinical features
Protein deiciency Delayed eruption
Vitamin A deficiency Retarded eruption.
Thickened mandibular process.
Vitamin B complex deficiency Retarded growth

41. Abnormal pressure habits and functional
aberrations:
Abnormal sucking
Thumb and finger sucking
Tongue thrusting
Improper deglutition
Speech defects
Mouth breathing
Tonsils and adenoids
bruxism

42. THUMB SUCKING
INCREASED
OVERBITE
RETROCLINED
LOWER
INCISORS
PROCLINED
UPPER
INCISOS

43. TONGUE THRUSTING
PROCLINED
ANTERIORS
ANTERIOR
OPEN BITE
POSTERIOR
CROSS BITE

44. NAIL BITING
DEEP
BITE
OVERJET
OVER
BITE

45. MOUTH
BREATHIG PROCLINED
ANTERIORS
CONTRACTED
UPPER ARCH
INCREASED
OVERJET

46. BRUXISM FRACTURE
OF TEETH
MOBILITY
TMJ PAIN

47. ❑POSTURE
• Poor postural habits are said to be a cause for
malocclusion
• May be associated with abnormal pressure and
muscle imbalance thereby increasing the risk of
malocclusion
• Childern who support their head by resting chin on
their hand are observed to have mandibular
deficiency

48. ❑ACCIDENTS AND TRAUMA
• Children are highly prone to injuries of the dento-
facial region during the early years of life when
they learns to crawl,walk or during play

49. ❑ANOMALIES IN NUMBER OF TEETH
• Presence of extra teeth or absence of one or more
teeth predisposes to malocclusion:
SUPERNUMERARY TEETH:
• Teeth that are extra to the normal complement are
termed supernumerary teeth that resemble normal
teeth are called supplemental teeth.

50. • Peg shape conical supernumerary teeth:

51. • BARREL SHAPED OR TUBERCULATE
SUPERNUMERARY:

52. • Supplemental teeth:

53. • ODONTOMES

54. • PROBLEM ASSOCIATED WITH SUPERNUMERARY
TEETH:
• Failure of eruption.
• Displacement or rotation of permanent teeth.
• Crowding.
• Pathology
• Incomplete space closure during orthodontic
treatment

55. • MISSING TEETH
• Congenitally missing teeth are by far more common
than supernumerary teeth and can occur in either
of the jaws.
• Congenitally absence of the teeth is reffered to as
hypodontia if some teeth are missing from the arch
or adontia if all of teeth are absent.
• If six or more permanent teeth are missing , the
used term ‘oligodontia’ is used.
• Hypodontia usually effects the last teeth in each
series,
3rd molars,upper laterals,second premolars.

56. • Following are some of the commonly missing
teeth in decreasing order of frequency.
• Third molars
• Maxillay lateral incisor
• Mandibular 2nd premolar
• Mandibular incisor
• Maxillary 2nd premolar

57. ❑ANOMALIES OF TOOTH SIZE
• The normal occlusion should be harmony between
the tooth size and arch length and also between
maxillary and mandibular tooth size.
• Macrodontia describes any tooth or teeth larger
than normal particular tooth type.
• Most common are upper central incisor and 2nd
premolar and lower 3rd molar

58. • Microdontia
• Seen in associated with downs syndrome.

59. • MACRODONTIA

60. • Abnormally shaped teeth predispose to
malocclusion
• Folllowing are the examples:
• Presence of peg shaped maxillary lateral
incisors is often accompanied by spacing and
migration of teeth.
• Abnormaly of tooth shape is the presence of an
abnormally large cingulum on a maxillary
incisor.
• Mandibular 2nd premolar may rarely have an
additional lingual cusp.

61. ABNORMAL LABIAL FRENUM
• Abnormalities of the maxillary labial frenum are
quite often associated with maxillary midline
spacing.
• Midline diastema may occur due to a number of
causes including presence of unerupted
mesiodens,anomalies of tooth size and number.

62. PREMATURE LOSS OF DECIDUOUS TEETH
• it refer to loss of a tooth before its permanent
successor is sufficiently advanced in development and
eruption occupy its place.
• Early loss of deciduous teeth can cause migration of
adjacent teeth into the space and can therefore prevent
the eruption of permanent successor.
• In a person having arch length deficiency or crowding
the early loss of deciduous teeth may worsen the
existing malocclusion.

63. PROLONGED RETENTION OF DECIDUOUS
TEETH
• This refer to a condition where there is undue
retention of primary teeth beyond the usual
eruption age of their permanent successors.
• Prolonged retention of primary anteriors usually
result in lingual or palatal eruption of their
permanent successors.

64. Reasons for prolonged retention of deciduoud teeth:
• Absence of underlying permanent teeth.
• Endocranial disturbances such as hypothyrodism
• Ankylosed deciduous teeth that fail to resorb
• Non vital deciduous teeth that do not resorb

65. DELAYED ERUPTION OF PERMANENT TEETH
• Congenital absence of the permanent tooth
• Presence of supernumerary tooth or pathology
such as odontomes can block the erupting
permanent tooth
• Endocranial disorder such as hypothyrodism
• Presence of deciduous root fragments that are not
resorbed can block the erupting permanent teeth.

66. • ABNORMAL ERUPTIVE PATH
• It could be due to arch length deficiency,presence
of supernumerary teeth,impacted teeth,retained
root fragment.
• The maxillary canines develop almost near the
floor of the orbit and travel down to their final
position in the oral cavity.

67. ANKYLOSIS
• It is a condition where in a part or whole of the
root surface is directly fused to the bone with the
absence of the intervening periodontal
membrane.

68. DENTAL CARIES
• Caries can lead to premature loss of deciduous or
permanent teeth thereby causing migration of
contiguous teeth,abnormal axial inclination and
supra eruption of opposing teeth.
• Proximal caries that has not been restored can cause
migration of the adjacent teeth into the space
leading to a redduction in arch length.

69. IMPROPER DENTAL RESTORATIONS
• Improper dental restorations may predispose to
malocclusion.
• Over countered occlusal restoration cause
premature contacts leading to functional shift
of the mandible during jaw closure
• Under-contoured occlusal restorations can
permit the opposing dentition to supraerupt.
• Proximal restorations that are under contoured
invariably result in loss of arch due to drifting of
adjacent teeth to occupy the space.