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Etiology of malocclusion


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TAriq hameed

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Etiology of malocclusion

  1. 1. ETIOLOGY OF MALOCCLUSION <ul><li>The various classifications proposed are: </li></ul><ul><li>• White and Gardiner's classification </li></ul><ul><li>• Salzmann's classification </li></ul><ul><li>• Moyer's classification </li></ul><ul><li>• Graber's classification. </li></ul>
  2. 2. White and Gardiner's classification <ul><li>This was one of the first attempts to classify malocclusion. </li></ul><ul><li>It tried to make a distinction between the skeletal and dental etiologic factors. </li></ul><ul><li>It also tried to distinguish between pre-eruptive and post-eruptive causes. </li></ul>
  3. 3. <ul><li>DENTAL BASE ABNORMALITIES </li></ul><ul><li>1. Antero-posterior mal relationship </li></ul><ul><li>2. Vertical mal relationship </li></ul><ul><li>3. Lateral mal relationship </li></ul><ul><li>4. Disproportion of size between teeth and basal bone </li></ul><ul><li>5. Congenital abnormalities. </li></ul>
  4. 4. <ul><li>PRE·ERUPTION ABNORMALITIES </li></ul><ul><li>1. Abnormalities in position of developing tooth germ </li></ul><ul><li>2. Missing teeth </li></ul><ul><li>3. Supernumerary teeth and teeth abnormal in form </li></ul><ul><li>4. Prolonged retention of deciduous teeth </li></ul><ul><li>5. Large labial frenum </li></ul><ul><li>6. Traumatic injury. </li></ul>
  5. 5. <ul><li>POST·ERUPTION ABNORMALITIES </li></ul><ul><li>1. Muscular </li></ul><ul><li>a. Active muscle force </li></ul><ul><li>b. Rest position of musculature </li></ul><ul><li>c. Sucking habits </li></ul><ul><li>d. Abnormalities in path of closure </li></ul><ul><li>2. Premature loss of deciduous teeth </li></ul><ul><li>3. Extraction of permanent teeth. </li></ul>
  6. 6. SALZMANN'S CLASSIFICATION <ul><li>Salzmann defined three definite stages in which malocclusions are likely to manifest: </li></ul><ul><li>1. The genotypic </li></ul><ul><li>2. The fetal environment </li></ul><ul><li>3. The postnatal environment. </li></ul><ul><li>Since different factors effect these different stages hence, the division of the etiologic factors into prenatal, postnatal, functional and environmental or acquired. </li></ul>
  7. 7. <ul><li>PRENATAL </li></ul><ul><li>1. Genetic - included malocclusions transmitted by genes, where the dentofacial anomalies may or may not be in evidence at birth. </li></ul><ul><li>2. Differentiative - malocclusions that are inborn, engrafted in the body in the prefunctional embryonic developmental stage. Can be subdivided into: </li></ul><ul><li>a. General -effect the body as a whole </li></ul><ul><li>b. Local -effect the face, jaws and teeth only. </li></ul><ul><li>3. Congenital - can be hereditary or acquired but existing at birth. Can be subdivided as: </li></ul><ul><li>a. General or constitutional </li></ul><ul><li>b. Local or dentofacial. </li></ul>
  8. 8. <ul><li>POSTNATAL </li></ul><ul><li>Developmental </li></ul><ul><li>A. General </li></ul><ul><li>a. Birth injuries </li></ul><ul><li>b. Abnormalities of relative rate of growth in different body organs </li></ul><ul><li>c. Hypo- or hypertonicity of muscles which may eventually affect the dentofacial development and function </li></ul><ul><li>d. Endocrine disturbances which may modify the growth pattern and eventually affect dentofacial growth </li></ul><ul><li>e. Nutritional disturbances </li></ul><ul><li>f. Childhood diseases that affect the growth pattern </li></ul><ul><li>g. Radiation. </li></ul>
  9. 9. <ul><li>B. Local </li></ul><ul><li>a. Abnormalities of the dentofacial complex: </li></ul><ul><li>1. Birth injuries of the head, face and jaws </li></ul><ul><li>2. Micro- or macrognathia </li></ul><ul><li>3. Micro- or macroglossia </li></ul><ul><li>4. Abnormal frenal attachments </li></ul><ul><li>5. Facial hemiatrophy. </li></ul><ul><li>b. Abnormalities of tooth development: </li></ul><ul><li>1. Delayed or premature eruption of the deciduous or permanent teeth </li></ul><ul><li>2. Delayed or premature shedding of deciduous teeth </li></ul><ul><li>3. Ectopic eruption </li></ul><ul><li>4. Impacted teeth </li></ul><ul><li>5. Aplasia of teeth. </li></ul>
  10. 10. <ul><li>FUNCTIONAL </li></ul><ul><li>A. General </li></ul><ul><li>1. Muscular hyper- or hypotonicity </li></ul><ul><li>2. Endocrine disturbances </li></ul><ul><li>3. Neurotrophic disturbances </li></ul><ul><li>4. Nutritional deficiencies </li></ul><ul><li>5. Postural defects </li></ul><ul><li>6. Respiratory disturbances (mouth breathing). </li></ul>
  11. 11. <ul><li>B. Local </li></ul><ul><li>1. Malfunction of forces exerted by the inclined planes of the cusps of the teeth </li></ul><ul><li>2. Loss of forces caused by failure of proximaI contact between teeth </li></ul><ul><li>3. Temporomandibular articulation disturbances. </li></ul><ul><li>4. Masticatory and facial muscular hypo- or hyperactivity </li></ul><ul><li>5. Faulty masticatory functions, especially during the tooth eruption period </li></ul><ul><li>6. Trauma from occlusion </li></ul><ul><li>7. Compromised periodontal condition. </li></ul>
  12. 12. <ul><li>ENVIRONMENTAL OR ACQUIRED </li></ul><ul><li>A. General </li></ul><ul><li>1. Disease can affect the dentofacial tissues directly or by affecting other parts of the body indirectly disturb the teeth and jaws. </li></ul><ul><li>2. Nutritional disturbances especially during the tooth formation stage. </li></ul><ul><li>3. Acquired endocrine disturbances that are not present at birth </li></ul><ul><li>4. Metabolic disturbances </li></ul><ul><li>5. Trauma , accidental injuries </li></ul><ul><li>6. Radiation. </li></ul><ul><li>7. Tumours. </li></ul><ul><li>8. Surgical pathologies. </li></ul>
  13. 13. <ul><li>B . Local </li></ul><ul><li>1. Disturbed forces of occlusion </li></ul><ul><li>2. Early loss of deciduous teeth </li></ul><ul><li>3. Prolonged retention of deciduous teeth </li></ul><ul><li>4. Delayed eruption of permanent teeth </li></ul><ul><li>5. Loss of permanent teeth </li></ul><ul><li>6. Periodontal diseases </li></ul><ul><li>7. Temporomandibular articulation disturbances </li></ul><ul><li>8. Infections of the oral cavity </li></ul><ul><li>9. Pressure habits </li></ul><ul><li>10. Traumatic injuries including fractures of the jaw bones. </li></ul>
  14. 14. MOyER'S CLASSIFICATION <ul><li>Moyer identified etiologic sites , from where the variations were expected to arise. These sites included: </li></ul><ul><li>the craniofacial skeleton, </li></ul><ul><li>the dentition, </li></ul><ul><li>the orofacial musculature, and </li></ul><ul><li>other 'soft tissues' of the masticatory system. </li></ul><ul><li>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. </li></ul>
  15. 15. <ul><li>1. Heredity </li></ul><ul><li>2. Developmental defects of unknown origin </li></ul><ul><li>3. Trauma: </li></ul><ul><li>a. Prenatal trauma and birth injuries </li></ul><ul><li>b. Postnatal trauma </li></ul><ul><li>4. Physical agents: </li></ul><ul><li>a. Premature extraction of primary teeth </li></ul><ul><li>b. Nature of food </li></ul><ul><li>5. Habits: </li></ul><ul><li>a. Thumb sucking and finger sucking </li></ul><ul><li>b. Tongue thrusting </li></ul><ul><li>c. Lip sucking and lip biting </li></ul><ul><li>d. Posture </li></ul><ul><li>e. Nail biting </li></ul><ul><li>f. Other habits </li></ul>
  16. 16. <ul><li>6. Diseases: </li></ul><ul><li>a. Systemic diseases </li></ul><ul><li>b. Endocrine disorders </li></ul><ul><li>c. Local diseases: </li></ul><ul><li>• Nasopharyngeal diseases and disturbed respiratory function </li></ul><ul><li>• Gingival and periodontal disease </li></ul><ul><li>• Tumours </li></ul><ul><li>• Caries: </li></ul><ul><li>- Premature loss of deciduous teeth </li></ul><ul><li>- Disturbances in sequence of eruption of permanent teeth </li></ul><ul><li>- Early loss of permanent teeth </li></ul><ul><li>7. Malnutrition. </li></ul>
  17. 17. GRABER'S CLASSIFICATION <ul><li>Graber divided the etiologic factors as general or local factors and presented a very comprehensive classification. </li></ul><ul><li>This helped in clubbing together of factors which make it easier to understand and associate a malocclusion with the etiologic factors. </li></ul>
  18. 18. <ul><li>GENERAL FACTORS </li></ul><ul><li>1. Heredity </li></ul><ul><li>2. Congenital </li></ul><ul><li>3. Environment: </li></ul><ul><li>a. Prenatal (trauma, maternal diet, German measles, material maternal metabolism, etc). </li></ul><ul><li>b. Postnatal (birth injury, cerebral palsy, TMJ injury) </li></ul><ul><li>4. Predisposing metabolic climate and disease: </li></ul><ul><li>a. Endocrine imbalance </li></ul><ul><li>b. Metabolic disturbances </li></ul><ul><li>c. Infectious diseases (poliomyelitis, etc). </li></ul>
  19. 19. <ul><li>5. Dietary problems (nutritional deficiency) </li></ul><ul><li>6. Abnormal pressure habits and functional aberrations: </li></ul><ul><li>a. Abnormal sucking </li></ul><ul><li>b. Thumb and finger sucking </li></ul><ul><li>c. Tongue thrust and tongue sucking </li></ul><ul><li>d. Lip and nail biting </li></ul><ul><li>e. Abnormal swallowing habits (improper deglutition) </li></ul><ul><li>f. Speech defects </li></ul><ul><li>g. Respiratory abnormalities (mouth breathing, etc.) </li></ul><ul><li>h. Tonsils and adenoids </li></ul><ul><li>i. Psychogenetics and bruxism </li></ul><ul><li>7. Posture </li></ul><ul><li>8. Trauma and accidents . </li></ul>
  20. 20. <ul><li>LOCAL FACTORS </li></ul><ul><li>1. Anomalies of number : </li></ul><ul><li>a. Supernumerary teeth </li></ul><ul><li>b. Missing teeth (congenital absence or loss due to accidents, caries, etc.). </li></ul><ul><li>2. Anomalies of tooth size </li></ul><ul><li>3. Anomalies of tooth shape </li></ul><ul><li>4. Abnormal labial frenum: mucosal barriers </li></ul><ul><li>5. Premature loss </li></ul><ul><li>6. Prolonged retention </li></ul>
  21. 21. <ul><li>7. Delayed eruption of permanent teeth </li></ul><ul><li>8. Abnormal eruptive path </li></ul><ul><li>9. Ankylosis </li></ul><ul><li>10. Dental caries </li></ul><ul><li>11. Improper dental restorations. </li></ul>
  22. 25. Infectious diseases
  24. 38. THANK YOU