56241260 Etiology of Malocclusion (1)

8/10/2019 56241260 Etiology of Malocclusion (1)

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SYED SOHAIB DAUD GILANI

FINAL YEAR BDS

ROLL#303


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MALOCCLUSION.

A malocclusionis a

misalignment of teeth

incorrect relation between the teeth of the twodental arches.

The term was coined byEdward Angle, the

"father of modern orthodontics", as a derivative

of occlusion, which refers to the manner in

which opposing teeth meet.
http://en.wikipedia.org/wiki/Edward_Anglehttp://en.wikipedia.org/wiki/Edward_Angle


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WHAT IS

MALOCCLUSION?

Malocclusion is not a disease, but a spectrum

representing biological variability/diversity

When the deviation from the normal reaches acertain degree of severity (threshold), then it is

termed malocclusion

What is of relevance is clinically significant

deviation from normal occlusion


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35%

5%

20%20%

20%


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WHY ETIOLOGY?

Better understanding of the condition

Prevention

Prediction

Management


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ETIOLOGY OF

MALOCCLUSION

The various classifications proposed are:

White and Gardiner's classificationSalzmann's classification

Moyer's classification

Graber's classification.


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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.


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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.


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PREERUPTION 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.


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POSTERUPTION 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.


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SALZMANN'S

CLASSIFICATIONSalzmann 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.


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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.


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POSTNATAL

Developmental

A. General

a. Birth injuries

b. Abnormalities of relative rate of growth in different bodyorgans

c. Hypo- or hypertonicity of muscles which may eventually

affect the dentofacial development and function

d. Endocrine disturbances which may modify the growthpattern and eventually affect dentofacial growth

e. Nutritional disturbances

f. Childhood diseases that affect the growth pattern

. Radiation.


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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.


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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).


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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


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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. Metabolicdisturbances

5. Trauma, accidental injuries

6. Radiation.

7. Tumours.


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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 jawbones.


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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.


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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 suckingb. Tongue thrusting

c. Lip sucking and lip biting

d. Posture

e. Nail biting

f. Other habits


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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.


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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).


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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


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LOCAL FACTORS

1. Anomalies of number:

a. Supernumerary teeth

b. Missing teeth (congenital absence or loss due toaccidents, caries, etc.).

2. Anomalies of tooth size

3. Anomalies of tooth shape 4. Abnormal labial frenum: mucosal barriers

5. Premature loss

6. Prolonged retention


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7. Delayed eruption of permanent teeth

8. Abnormal eruptive path

9. Ankylosis

10. Dental caries

11. Improper dental restorations.


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Infectious diseases


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DIETARY PROBLEMS


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DIETARY PROBLEMS

(NUTRITIONAL DEFICIENCY)


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RESPIRATORY PATTERN

ADENOID FACIESTHRESHOLD??


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DIGIT SUCKING HABIT

Threshold6 hrs


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TONGUE THRUSTING


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ETIOLOGY IN

CONTEMPORARY

PERSPECTIVE

Etiology of most malocclusions are

unknown

Role of genetic and environmentalinfluences

Skeletal traits have greater genetic

influence Dental traits have relatively greater

environmental influence


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THANK YOU

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56241260 Etiology of Malocclusion (1)

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