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MALOCCLUSION.MALOCCLUSION.

A A malocclusionmalocclusion is a  is a misalignment of teeth misalignment of teeth incorrect relation between the teeth of the two incorrect relation between the teeth of the two

dental arches.dental arches. The term was coined byThe term was coined byEdwardEdward Angle Angle, the , the

"father of modern orthodontics", as a derivative "father of modern orthodontics", as a derivative of of occlusionocclusion, which refers to the manner in , which refers to the manner in which opposing teeth meet. which opposing teeth meet.

WHAT IS WHAT IS MALOCCLUSION?MALOCCLUSION?

Malocclusion is Malocclusion is notnot a disease, but a a disease, but a spectrumspectrum representing biological variability/diversityrepresenting biological variability/diversity

When the deviation from the normal reaches a When the deviation from the normal reaches a certain degree of severity (certain degree of severity (thresholdthreshold), then it is ), then it is termed malocclusion termed malocclusion

What is of relevance is “clinically significant” What is of relevance is “clinically significant” deviation from normal occlusiondeviation from normal occlusion

35%

5%

20%20%

20%

WHY ETIOLOGY?WHY ETIOLOGY?

Better understanding of the conditionBetter understanding of the condition PreventionPrevention PredictionPrediction ManagementManagement

ETIOLOGY OF ETIOLOGY OF MALOCCLUSIONMALOCCLUSION

The various classifications proposed are:The various classifications proposed are:

• • White and Gardiner's classificationWhite and Gardiner's classification

• • Salzmann's classificationSalzmann's classification

• • Moyer's classificationMoyer's classification

• • Graber's classification.Graber's classification.

White and Gardiner's White and Gardiner's classificationclassification

This was one of the first attempts to classify This was one of the first attempts to classify malocclusion.malocclusion.

It tried to make a distinction between the It tried to make a distinction between the skeletal and skeletal and dental etiologic factors. dental etiologic factors.

It also tried to distinguish between It also tried to distinguish between pre-eruptive and pre-eruptive and post-eruptive causes.post-eruptive causes.

DENTAL BASE ABNORMALITIESDENTAL BASE ABNORMALITIES

1. Antero-posterior mal relationship1. Antero-posterior mal relationship 2. Vertical mal relationship2. Vertical mal relationship 3. Lateral mal relationship3. Lateral mal relationship 4. Disproportion of size between teeth and basal bone4. Disproportion of size between teeth and basal bone 5. Congenital abnormalities.5. Congenital abnormalities.

PRE·ERUPTION ABNORMALITIESPRE·ERUPTION ABNORMALITIES

1. Abnormalities in position of developing tooth germ1. Abnormalities in position of developing tooth germ 2. Missing teeth2. Missing teeth 3. Supernumerary teeth and teeth abnormal in form3. Supernumerary teeth and teeth abnormal in form 4. Prolonged retention of deciduous teeth4. Prolonged retention of deciduous teeth 5. Large labial frenum5. Large labial frenum 6. Traumatic injury.6. Traumatic injury.

POST·ERUPTION ABNORMALITIESPOST·ERUPTION ABNORMALITIES

1. Muscular1. Muscular

a. Active muscle forcea. Active muscle force

b. Rest position of musculatureb. Rest position of musculature

c. Sucking habitsc. Sucking habits

d. Abnormalities in path of closured. Abnormalities in path of closure 2. Premature loss of deciduous teeth2. Premature loss of deciduous teeth 3. Extraction of permanent teeth.3. Extraction of permanent teeth.

SALZMANN'S SALZMANN'S CLASSIFICATIONCLASSIFICATION

Salzmann defined Salzmann defined three definite stages three definite stages in which in which malocclusions are likely to manifest:malocclusions are likely to manifest:

1. The genotypic1. The genotypic 2. The fetal environment2. The fetal environment 3. The postnatal environment.3. The postnatal environment.

Since different factors effect these different stages Since different factors effect these different stages hence, the division of the etiologic factors into hence, the division of the etiologic factors into prenatal, postnatal, functional and environmental prenatal, postnatal, functional and environmental or acquired.or acquired.

PRENATALPRENATAL 1. 1. GeneticGenetic - included malocclusions transmitted by genes, where the - included malocclusions transmitted by genes, where the

dentofacial anomalies may or may not be in evidence at birth.dentofacial anomalies may or may not be in evidence at birth. 2. 2. DifferentiativeDifferentiative - malocclusions that are inborn, engrafted in the - malocclusions that are inborn, engrafted in the

body in the prefunctional embryonic developmental stage. Can be body in the prefunctional embryonic developmental stage. Can be subdivided into:subdivided into:

a. a. GeneralGeneral-effect the body as a whole-effect the body as a whole

b. b. LocalLocal-effect the face, jaws and teeth only.-effect the face, jaws and teeth only. 3. 3. CongenitalCongenital - can be hereditary or acquired but existing at birth. - can be hereditary or acquired but existing at birth.

Can be subdivided as:Can be subdivided as:

a. General or constitutionala. General or constitutional

b. Local or dentofacial.b. Local or dentofacial.

POSTNATALPOSTNATAL DevelopmentalDevelopmental A. GeneralA. General

a. Birth injuriesa. Birth injuries

b. Abnormalities of relative rate of growth in different body organsb. Abnormalities of relative rate of growth in different body organs

c. Hypo- or hypertonicity of muscles which may eventually affect c. Hypo- or hypertonicity of muscles which may eventually affect the dentofacial development and functionthe dentofacial development and function

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

e. Nutritional disturbancese. Nutritional disturbances

f. Childhood diseases that affect the growth patternf. Childhood diseases that affect the growth pattern

g. Radiation.g. Radiation.

B. LocalB. Local

a. Abnormalities of the dentofacial complex:a. Abnormalities of the dentofacial complex: 1. Birth injuries of the head, face and jaws1. Birth injuries of the head, face and jaws 2. Micro- or macrognathia2. Micro- or macrognathia 3. Micro- or macroglossia3. Micro- or macroglossia 4. Abnormal frenal attachments4. Abnormal frenal attachments 5. Facial hemiatrophy.5. Facial hemiatrophy.

b. Abnormalities of tooth development:b. Abnormalities of tooth development: 1. Delayed or premature eruption of the deciduous or permanent teeth1. Delayed or premature eruption of the deciduous or permanent teeth 2. Delayed or premature shedding of deciduous teeth2. Delayed or premature shedding of deciduous teeth 3. Ectopic eruption3. Ectopic eruption 4. Impacted teeth4. Impacted teeth 5. Aplasia of teeth.5. Aplasia of teeth.

FUNCTIONALFUNCTIONAL

A. GeneralA. General 1. Muscular hyper- or hypotonicity1. Muscular hyper- or hypotonicity 2. Endocrine disturbances2. Endocrine disturbances 3. Neurotrophic disturbances3. Neurotrophic disturbances 4. Nutritional deficiencies4. Nutritional deficiencies 5. Postural defects5. Postural defects 6. Respiratory disturbances (mouth breathing).6. Respiratory disturbances (mouth breathing).

B. LocalB. Local 1. Malfunction of forces exerted by the inclined planes of the 1. Malfunction of forces exerted by the inclined planes of the

cusps of the teethcusps of the teeth 2. Loss of forces caused by failure of proximaI contact 2. Loss of forces caused by failure of proximaI contact

between teethbetween teeth 3. Temporomandibular articulation disturbances.3. Temporomandibular articulation disturbances. 4. Masticatory and facial muscular hypo- or hyperactivity4. Masticatory and facial muscular hypo- or hyperactivity 5. Faulty masticatory functions, especially during the tooth 5. Faulty masticatory functions, especially during the tooth

eruption perioderuption period 6. Trauma from occlusion6. Trauma from occlusion 7. Compromised periodontal condition.7. Compromised periodontal condition.

ENVIRONMENTAL OR ACQUIREDENVIRONMENTAL OR ACQUIRED

A. GeneralA. General 1. Disease can affect the dentofacial tissues directly or by affecting 1. Disease can affect the dentofacial tissues directly or by affecting

other parts of the body indirectly disturb the teeth and jaws.other parts of the body indirectly disturb the teeth and jaws. 2. 2. NutritionalNutritional disturbances especially during the tooth formation disturbances especially during the tooth formation

stage.stage. 3. 3. Acquired endocrine Acquired endocrine disturbances that are not present at birthdisturbances that are not present at birth 4. 4. MetabolicMetabolic disturbances disturbances 5. 5. TraumaTrauma, accidental injuries, accidental injuries 6. Radiation.6. Radiation. 7. Tumours.7. Tumours. 8. Surgical pathologies.8. Surgical pathologies.

BB. Local. Local 1. Disturbed forces of occlusion1. Disturbed forces of occlusion 2. Early loss of deciduous teeth2. Early loss of deciduous teeth 3. Prolonged retention of deciduous teeth3. Prolonged retention of deciduous teeth 4. Delayed eruption of permanent teeth4. Delayed eruption of permanent teeth 5. Loss of permanent teeth5. Loss of permanent teeth 6. Periodontal diseases6. Periodontal diseases 7. Temporomandibular articulation disturbances7. Temporomandibular articulation disturbances 8. Infections of the oral cavity8. Infections of the oral cavity 9. Pressure habits9. Pressure habits 10. Traumatic injuries including fractures of the jaw bones.10. Traumatic injuries including fractures of the jaw bones.

MOyER'S CLASSIFICATIONMOyER'S CLASSIFICATION Moyer identified Moyer identified etiologic sitesetiologic sites, from where the , from where the

variations were expected to arise. These sites variations were expected to arise. These sites included:included:

A)A)the craniofacial skeleton, the craniofacial skeleton,

B)B)the dentition, the dentition,

C)C)the orofacial musculature, and the orofacial musculature, and

D)D)other 'soft tissues' of the masticatory system. other 'soft tissues' of the masticatory system.

He based his classification on the premise that various He based his classification on the premise that various factors may contribute to cause variations at these factors may contribute to cause variations at these sites, more often in groups rather than individually.sites, more often in groups rather than individually.

1. Heredity1. Heredity 2. Developmental defects of unknown origin2. Developmental defects of unknown origin 3. Trauma:3. Trauma:

a. Prenatal trauma and birth injuriesa. Prenatal trauma and birth injuries

b. Postnatal traumab. Postnatal trauma 4. Physical agents:4. Physical agents:

a. Premature extraction of primary teetha. Premature extraction of primary teeth

b. b. Nature of foodNature of food 5. Habits:5. Habits:

a. Thumb sucking and finger suckinga. Thumb sucking and finger sucking

b. Tongue thrustingb. Tongue thrusting

c. Lip sucking and lip bitingc. Lip sucking and lip biting d. Postured. Posture e. Nail bitinge. Nail biting f. Other habitsf. Other habits

6. Diseases:6. Diseases:

a. Systemic diseasesa. Systemic diseases

b. Endocrine disordersb. Endocrine disorders

c. Local diseases:c. Local diseases: • • Nasopharyngeal diseases and disturbed respiratory functionNasopharyngeal diseases and disturbed respiratory function • • Gingival and periodontal diseaseGingival and periodontal disease • • TumoursTumours • • Caries:Caries:

- Premature loss of deciduous teeth- Premature loss of deciduous teeth

- Disturbances in sequence of eruption of permanent teeth- Disturbances in sequence of eruption of permanent teeth

- Early loss of permanent teeth- Early loss of permanent teeth 7. Malnutrition.7. Malnutrition.

GRABER'S CLASSIFICATIONGRABER'S CLASSIFICATION

Graber divided the etiologic factors as Graber divided the etiologic factors as general or general or local factorslocal factors and presented a very and presented a very comprehensive comprehensive classification.classification.

This helped in clubbing together of factors which make This helped in clubbing together of factors which make it easier to understand and associate a malocclusion it easier to understand and associate a malocclusion with the etiologic factors.with the etiologic factors.

GENERAL FACTORSGENERAL FACTORS 1. Heredity1. Heredity 2. Congenital2. Congenital 3. Environment:3. Environment:

a. Prenatal (trauma, maternal diet, German measles, material a. Prenatal (trauma, maternal diet, German measles, material maternal metabolism, etc).maternal metabolism, etc).

b. Postnatal (birth injury, cerebral palsy, TMJ injury)b. Postnatal (birth injury, cerebral palsy, TMJ injury) 4. Predisposing metabolic climate and disease:4. Predisposing metabolic climate and disease:

a. Endocrine imbalancea. Endocrine imbalance

b. Metabolic disturbancesb. Metabolic disturbances

c. Infectious diseases (poliomyelitis, etc).c. Infectious diseases (poliomyelitis, etc).

5. Dietary problems (nutritional deficiency)5. Dietary problems (nutritional deficiency) 6. Abnormal pressure habits and functional aberrations:6. Abnormal pressure habits and functional aberrations:

a. Abnormal suckinga. Abnormal sucking

b. Thumb and finger suckingb. Thumb and finger sucking

c. Tongue thrust and tongue suckingc. Tongue thrust and tongue sucking

d. Lip and nail bitingd. Lip and nail biting

e. Abnormal swallowing habits (improper deglutition)e. Abnormal swallowing habits (improper deglutition)

f. Speech defectsf. Speech defects

g. Respiratory abnormalities (mouth breathing, etc.)g. Respiratory abnormalities (mouth breathing, etc.)

h. Tonsils and adenoidsh. Tonsils and adenoids

i. Psychogenetics and bruxismi. Psychogenetics and bruxism 7. Posture7. Posture 8. Trauma and accidents8. Trauma and accidents..

LOCAL FACTORSLOCAL FACTORS

1. Anomalies of 1. Anomalies of numbernumber::

a. Supernumerary teetha. Supernumerary teeth

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

2. Anomalies of 2. Anomalies of tooth sizetooth size 3. Anomalies of 3. Anomalies of tooth shapetooth shape 4. Abnormal labial frenum: mucosal barriers4. Abnormal labial frenum: mucosal barriers 5. Premature loss5. Premature loss 6. Prolonged retention6. Prolonged retention

7. Delayed eruption of permanent teeth7. Delayed eruption of permanent teeth 8. Abnormal eruptive path8. Abnormal eruptive path 9. Ankylosis9. Ankylosis 10. Dental caries10. Dental caries 11. Improper dental restorations.11. Improper dental restorations.

Infectious diseasesInfectious diseases

DIETARY PROBLEMSDIETARY PROBLEMS(NUTRITIONAL DEFICIENCY)(NUTRITIONAL DEFICIENCY)

RESPIRATORY PATTERNRESPIRATORY PATTERN

ADENOID FACIES – THRESHOLD??

DIGIT SUCKING HABITDIGIT SUCKING HABIT

Threshold – 6 hrs

TONGUE THRUSTINGTONGUE THRUSTING

ETIOLOGY IN ETIOLOGY IN CONTEMPORARY CONTEMPORARY PERSPECTIVEPERSPECTIVE

Etiology of most malocclusions are Etiology of most malocclusions are unknownunknown

Role of genetic and environmental Role of genetic and environmental influencesinfluences

Skeletal traits have greater genetic Skeletal traits have greater genetic influenceinfluence

Dental traits have relatively greater Dental traits have relatively greater environmental influenceenvironmental influence

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