ETIOLOGY OF MALOCCLUSION

1. ETIOLOGY OF MALOCCLUSION
• The various classifications proposed are:
• White and Gardiner's classification
• Salzmann's classification
• Moyer's classification
• Graber's classification.

2. White and Gardiner's classification
• This was one of the first attempts to classify malocclusion.
• It tried to make a distinction between the skeletal and
dental etiologic factors.
• It also tried to distinguish between pre-eruptive and post-
eruptive causes.

3. DENTAL BASE ABNORMALITIES
• 1. Antero-posterior mal relationship
• 2. Vertical mal relationship
• 3. Lateral mal relationship
• 4. Disproportion of size between teeth and basal bone
• 5. Congenital abnormalities.

4. PRE·ERUPTION ABNORMALITIES
• 1. Abnormalities in position of developing tooth germ
• 2. Missing teeth
• 3. Supernumerary teeth and teeth abnormal in form
• 4. Prolonged retention of deciduous teeth
• 5. Large labial frenum
• 6. Traumatic injury.

5. POST·ERUPTION ABNORMALITIES
• 1. Muscular
a. Active muscle force
b. Rest position of musculature
c. Sucking habits
d. Abnormalities in path of closure
• 2. Premature loss of deciduous teeth
• 3. Extraction of permanent teeth.

6. SALZMANN'S CLASSIFICATION
Salzmann defined three definite stages in which
malocclusions are likely to manifest:
• 1. The genotypic
• 2. The fetal environment
• 3. The postnatal environment.
• Since different factors effect these different stages hence,
the division of the etiologic factors into prenatal,
postnatal, functional and environmental or acquired.

7. PRENATAL
• 1. Genetic - included malocclusions transmitted by genes,
where the dentofacial anomalies may or may not be in
evidence at birth.
• 2. Differentiative - malocclusions that are inborn, engrafted in
the body in the prefunctional embryonic developmental stage.
Can be subdivided into:
a. General-effect the body as a whole
b. Local-effect the face, jaws and teeth only.
• 3. Congenital - can be hereditary or acquired but existing at
birth. Can be subdivided as:
a. General or constitutional
b. Local or dentofacial.

8. POSTNATAL
• Developmental
• A. General
a. Birth injuries
b. Abnormalities of relative rate of growth in different body
organs
c. Hypo- or hypertonicity of muscles which may eventually affect
the dentofacial development and function
d. Endocrine disturbances which may modify the growth pattern
and eventually affect dentofacial growth
e. Nutritional disturbances
f. Childhood diseases that affect the growth pattern
g. Radiation.

9. • B. Local
a. Abnormalities of the dentofacial complex:
• 1. Birth injuries of the head, face and jaws
• 2. Micro- or macrognathia
• 3. Micro- or macroglossia
• 4. Abnormal frenal attachments
• 5. Facial hemiatrophy.
b. Abnormalities of tooth development:
• 1. Delayed or premature eruption of the deciduous or permanent
teeth
• 2. Delayed or premature shedding of deciduous teeth
• 3. Ectopic eruption
• 4. Impacted teeth
• 5. Aplasia of teeth.

10. FUNCTIONAL
A. General
• 1. Muscular hyper- or hypotonicity
• 2. Endocrine disturbances
• 3. Neurotrophic disturbances
• 4. Nutritional deficiencies
• 5. Postural defects
• 6. Respiratory disturbances (mouth breathing).

11. B. Local
• 1. Malfunction of forces exerted by the inclined planes of
the cusps of the teeth
• 2. Loss of forces caused by failure of proximaI contact
between teeth
• 3. Temporomandibular articulation disturbances.
• 4. Masticatory and facial muscular hypo- or hyperactivity
• 5. Faulty masticatory functions, especially during the tooth
eruption period
• 6. Trauma from occlusion
• 7. Compromised periodontal condition.

12. ENVIRONMENTAL OR ACQUIRED
A. General
• 1. Disease can affect the dentofacial tissues directly or by affecting
other parts of the body indirectly disturb the teeth and jaws.
• 2. Nutritional disturbances especially during the tooth formation
stage.
• 3. Acquired endocrine disturbances that are not present at birth
• 4. Metabolic disturbances
• 5. Trauma, accidental injuries
• 6. Radiation.
• 7. Tumours.
• 8. Surgical pathologies.

13. B. Local
• 1. Disturbed forces of occlusion
• 2. Early loss of deciduous teeth
• 3. Prolonged retention of deciduous teeth
• 4. Delayed eruption of permanent teeth
• 5. Loss of permanent teeth
• 6. Periodontal diseases
• 7. Temporomandibular articulation disturbances
• 8. Infections of the oral cavity
• 9. Pressure habits
• 10. Traumatic injuries including fractures of the jaw bones.

14. MOyER'S CLASSIFICATION
• Moyer identified etiologic sites, from where the variations
were expected to arise. These sites included:
A)the craniofacial skeleton,
B) the dentition,
C) the orofacial musculature, and
D)other 'soft tissues' of the masticatory system.
He based his classification on the premise that various factors
may contribute to cause variations at these sites, more
often in groups rather than individually.

15. • 1. Heredity
• 2. Developmental defects of unknown origin
• 3. Trauma:
a. Prenatal trauma and birth injuries
b. Postnatal trauma
• 4. Physical agents:
a. Premature extraction of primary teeth
b. Nature of food
• 5. Habits:
a. Thumb sucking and finger sucking
b. Tongue thrusting
c. Lip sucking and lip biting
• d. Posture
• e. Nail biting
• f. Other habits

16. • 6. Diseases:
a. Systemic diseases
b. Endocrine disorders
c. Local diseases:
• • Nasopharyngeal diseases and disturbed respiratory function
• • Gingival and periodontal disease
• • Tumours
• • Caries:
- Premature loss of deciduous teeth
- Disturbances in sequence of eruption of permanent teeth
- Early loss of permanent teeth
• 7. Malnutrition.

17. GRABER'S CLASSIFICATION
• Graber divided the etiologic factors as general or local
factors and presented a very comprehensive classification.
• This helped in clubbing together of factors which make it
easier to understand and associate a malocclusion with the
etiologic factors.

18. GENERAL FACTORS
• 1. Heredity
• 2. Congenital
• 3. Environment:
a. Prenatal (trauma, maternal diet, German measles,
material maternal metabolism, etc).
b. Postnatal (birth injury, cerebral palsy, TMJ injury)
• 4. Predisposing metabolic climate and disease:
a. Endocrine imbalance
b. Metabolic disturbances
c. Infectious diseases (poliomyelitis, etc).

19. • 5. Dietary problems (nutritional deficiency)
• 6. Abnormal pressure habits and functional aberrations:
a. Abnormal sucking
b. Thumb and finger sucking
c. Tongue thrust and tongue sucking
d. Lip and nail biting
e. Abnormal swallowing habits (improper deglutition)
f. Speech defects
g. Respiratory abnormalities (mouth breathing, etc.)
h. Tonsils and adenoids
i. Psychogenetics and bruxism
• 7. Posture

20. • LOCAL FACTORS
• 1. Anomalies of number:
a. Supernumerary teeth
b. Missing teeth (congenital absence or loss due to accidents,
caries, etc.).
• 2. Anomalies of tooth size
• 3. Anomalies of tooth shape
• 4. Abnormal labial frenum: mucosal barriers
• 5. Premature loss
• 6. Prolonged retention

21. • 7. Delayed eruption of permanent teeth
• 8. Abnormal eruptive path
• 9. Ankylosis
• 10. Dental caries
• 11. Improper dental restorations.

25. Infectious diseases

27. DIETARY PROBLEMS
(NUTRITIONAL DEFICIENCY)

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