Etiology of Malocclusion II

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Introduction to Orthodontics
Fifth Year

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Etiology of Malocclusion II

  1. 1. Eighth Lecture Etiology of Malocclusion
  2. 2. General Causes 1.Evolution: 2. Congenital malformation: 3. Endocrinal disturbances: 4. Nutritional deficiency 5. Pathological Conditions: March 5, 2012 Local Causes 1. Congenital missing teeth: 2 Supernumerary teeth: Dr. Ahmed Basyouni 2
  3. 3. Continue B. Local Causes 3.Teeth of abnormal size and form: Size of teeth is largely determined by hereditary. This includes: a. Peg-lateral is the most frequent departure from normal. b. Gemination c. Fusion Fusion March 5, 2012 Dr. Ahmed Basyouni 3
  4. 4. B. Local Causes 3 Teeth of abnormal size and form: d. Macro- or microdontism e. Odontomes, Dens-in-dent, Hutchinson’s teeth & Mulberry molars. Jacket crowning, bridges or space closing may be necessary. March 5, 2012 Dr. Ahmed Basyouni L S 4
  5. 5. B. Local Causes 4. Abnormal path of eruption: This is usually a secondary manifestation of the following: a. Severe crowding & totally inadequate space to accommodate all teeth, so deflection of the erupting tooth occurs. March 5, 2012 Dr. Ahmed Basyouni 5
  6. 6. B. Local Causes 4. Abnormal path of eruption: b. Supernumerary tooth. c. Retained decid. teeth. March 5, 2012 Dr. Ahmed Basyouni Supplemental Teeth 6
  7. 7. B. Local Causes 4 Abnormal path of eruption: d. Trauma to decid. Teeth may turn the developing successor in an abnormal direction. e. Mechanical interference by early orthodontic treatment. f. Eruption cyst. March 5, 2012 Dr. Ahmed Basyouni 7
  8. 8. B. Local Causes 4 Abnormal path of eruption g. Ectopic eruption: a permanent tooth during its eruption may cause resorption of neighboring tooth. The most common is maxillary first molar may cause abnormal resorption of maxillary second decid. Molar, when erupts under the distal convexity of this tooth (Es). March 5, 2012 Dr. Ahmed Basyouni 8
  9. 9. B. Local Causes 5. Abnormal labial frenum: Before eruption of teeth, the upper median labial frenum is continuous with incisive papilla. As growth proceeds and teeth erupt, attachment of the frenum recedes to a midway between the alveolar border and reflection of lip mucosa (mucolabial fold). March 5, 2012 Dr. Ahmed Basyouni 9
  10. 10. B. Local Causes 5. Abnormal labial frenum: In the abnormal condition the frenum is wide and thick and passes between permanent central incisors into the incisive papilla, producing a wide space between central incisors called Median Diastema. Palatal mucosa blanches on raising upper lip. March 5, 2012 Dr. Ahmed Basyouni 10
  11. 11. B. Local Causes 5. Abnormal labial frenum: Treatment consists of bringing the central incisors together orthodontically first, then excising the frenum (Frenectomy), scar tissue formed will serve to help in retention. March 5, 2012 Dr. Ahmed Basyouni 11
  12. 12. 6. Abnormal pressure habits: B. Local Causes a. Thumb sucking: It is repeated forceful sucking of the thumb with associated strong buccal and lip contractions. Clinical aspect of this problem divided into 3 phases: March 5, 2012 Dr. Ahmed Basyouni 12
  13. 13. B. Local Causes 6. Abnormal pressure habits: a. Thumb sucking: Phase I: Normal & subclinically significant thumb sucking: This extends from 3 months to 2 years, as most infants display a certain amount of thumb sucking during this period. Particularly at time of weaning. March 5, 2012 Dr. Ahmed Basyouni 13
  14. 14. B. Local Causes 6. Abnormal pressure habits: a. Thumb sucking: Phase II: Clinically significant thumbsucking: This extends roughly from 2-4 years, sucking practiced during this time will result in temporary damage. If the child drops the habit by end of this period, he may have no more than reduced overbite & increased overjet with some spacing in the maxillary arch, and there may be also slight crowding of lower anterior teeth. March 5, 2012 Dr. Ahmed Basyouni Phase II 14
  15. 15. B. Local Causes 6. Abnormal pressure habits: a. Thumb sucking: Phase III: Active thumb-sucking: Child continuation of this habit after 4 years will develop malocclusion. Type of malocclusion is dependent upon the position of the thumb, associated musc. Contraction of the cheeks and position of the mandible during sucking. March 5, 2012 Dr. Ahmed Basyouni 15
  16. 16. B. Local Causes 6. Abnormal pressure habits: a. Thumb sucking: Effects: 1. Protraction of maxillary anterior teeth & mandibular retraction. 2. Anterior open bite. 3. Contraction of the maxillary arch and high vault. 4. Hypotonic upper lip and lower lip is usually caught beneath maxillary incisors, forcing them further forward. March 5, 2012 Dr. Ahmed Basyouni 16
  17. 17. b.Tongue thrusting: B. Local Causes 6. Abnormal pressure habits: It is usually of two types: 1. Simple: in which tongue thrust is associated with a normal or teeth together swallow. This usually accompanies thumb sucking habit, as it is necessary for the tongue to thrust forward through the open bite to maintain anterior seal with lips during swallowing. March 5, 2012 Dr. Ahmed Basyouni 17
  18. 18. B. Local Causes 6. Abnormal pressure habits: b.Tongue thrusting: 2. Complex: is originating from tonsillitis, or pharyngitis. When tonsils are swollen & sore, the root of the tongue encroaches on the enlarged pillars. This causes pain and reflexly the mandible is dropped down, teeth become separated and tongue is thrust between them during last stage of swallowing. March 5, 2012 Dr. Ahmed Basyouni 18
  19. 19. B. Local Causes 6. Abnormal pressure habits: b.Tongue thrusting: Anterior tongue thrust is an etiologic factor of anterior open bite as tongue will prevent normal vertical development of the dentoalveolar structures anteriorly. March 5, 2012 Dr. Ahmed Basyouni 19
  20. 20. Habit breaking appliance March 5, 2012 Dr. Ahmed Basyouni 20
  21. 21. B. Local Causes 6. Abnormal pressure habits: c. Nail biting: Nail biting is mentioned as a cause of tooth malposition. It is absent under 3 years, there is a rapid increase at 6 years of age. The incidence of nail biting drops sharply after 18 years. Clinical examination may reveal crowding, rotation and attrition of the incisal edges of the incisor teeth. Most commonly is seen in excitable children. March 5, 2012 Dr. Ahmed Basyouni 21
  22. 22. B. Local Causes 6. Abnormal pressure habits: d. Abnormal swallowing: Teeth are often separated, tongue thrusts forward into the excessive overjet and dorsum of the tongue drops away from the palatal vault. Enlarged tonsils may accentuate tongue thrust habit . March 5, 2012 Dr. Ahmed Basyouni 22
  23. 23. B. Local Causes 6. Abnormal pressure habits: e. Mouth breathing: Mouth breathers seem to have high incidence of malocclusions. Mouth breathing is prevented by 3 sphincter mechanism: 1. Anterior sphincter: formed by the lips. 2. Intermediate sphincter: formed by tongue and hard palate. 3. Posterior sphincter: formed between the soft palate & the dorsum of the tongue. March 5, 2012 Dr. Ahmed Basyouni 23
  24. 24. B. Local Causes 6. Abnormal pressure habits: e. Mouth breathing: Causes: 1. Partial nasal obstruction: due to a. deviated septum b. narrow nasal passages. c. Inflammatory reaction of nasal mucous membrane. d. Allergic reaction of nasal mucosa. e. Obstructive adenoids in postnasal space. March 5, 2012 Dr. Ahmed Basyouni 24
  25. 25. B. Local Causes 6. Abnormal pressure habits: e. Mouth breathing: Continu. Causes of mouth breathing: 2. Habit: formed during presence of one or more of the obstructive causes, and persisted after removal of the cause (habitual mouth breathing). 3. An increased free way space: in rare cases tongue falls away from the palate and therefore lips do not form an anterior seal. This type found in complete absence of any upper respiratory obstruction (True mouth breathing). March 5, 2012 Dr. Ahmed Basyouni 25
  26. 26. B. Local Causes 6. Abnormal pressure habits: e. Mouth breathing: Continu. Causes of mouth breathing: 4. Air hunger e.g. in children with heart disease and as a normal behaviour during exercise. March 5, 2012 Dr. Ahmed Basyouni 26
  27. 27. B. Local Causes 6. Abnormal pressure habits: e. Mouth breathing: Effects: Typical mouth breathing syndrome characterized by: 1. Contracted maxillary arch. 2. Protrusion of upper incisors. 3. Crowding of anterior teeth in both arches. March 5, 2012 Dr. Ahmed Basyouni 27
  28. 28. B. Local Causes 6. Abnormal pressure habits: e. Mouth breathing: Effects: lip. 4. Hypertrophy of the lower 5. Hypotonic and short upper lip & frequently increased over bite. 6. The molar relationship may be normal or distocclusion. March 5, 2012 Dr. Ahmed Basyouni 28
  29. 29. Summary General Causes 1.Evolution: 2. Congenital malformation: 3. Endocrinal disturbances: 4. Nutritional deficiency 5. Pathological Conditions: March 5, 2012 Dr. Ahmed Basyouni 29
  30. 30. Continue B. Local Causes Summary Local Causes 1. Congenital missing teeth: 2. Supernumerary teeth: 3. Teeth of abnormal size and form: 4. Abnormal path of eruption: 5. Abnormal labial frenum: 6. Abnormal pressure habits: a. Thumb sucking: b. Tongue thrusting: c. Nail biting: d. Abnormal swallowing: e. Mouth breathing: March 5, 2012 Dr. Ahmed Basyouni 30
  31. 31. March 5, 2012 Dr. Ahmed Basyouni 31

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