Etiology of malocclusion local factors /certified fixed orthodontic courses by Indian dental academy


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Etiology of malocclusion local factors /certified fixed orthodontic courses by Indian dental academy

  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education
  3. 3. LOCAL FACTORS 1. Anomalies of number a) Supernumerary teeth. b) Missing teeth (congenital absence or loss due to trauma,caries,etc.) 2. Anomalies of tooth size. 3. Anomalies of tooth shape. 4. Abnormal labial frenum.
  4. 4. 5. Premature loss 6. Prolonged retention 7. Delayed eruption of permanent teeth 8. Abnormal eruptive path 9. Ankylosis 10. Dental caries 11. Improper dental restorations
  5. 5. 1) Anomalies of number A) Supernumerary teeth: Supernumerary teeth is a teeth, which is various in size , shape and location when compared to the normal teeth. B)Supplemental teeth : Supplemental teeth is a teeth ,which is closely resembles the particular group of teeth. This is most commonly seen in premolar region and lateral incisor region.
  6. 6.  Supernumerary teeth result from disturbances during the initiation and proliferation stages of dental development.  Supernumerary teeth occur most commonly in the maxilla..  The most commonly seen supernumerary teeth is mesiodens.  Mesiodens is a small tooth with a cone shaped crown and short root.
  7. 7. Supernumerary teeth
  8. 8. Supernumerary teeth
  9. 9. It is seen between the two maxillary central incisors. The presence of teeth obviously has great potential to disturb normal occlusal development.  The frequency of other supernumerary teeth are paramolars and distomolars. Multiple supernumerary teeth are seen in cleidocranial dysplasia.
  10. 10. Cleidocranial dysplasia Cleidocranial dysplasia is characterized by - Abnormalities of skull,teeth,jaws and shoulder girdle. -The defect of shoulder girdle ranges from complete absence of clavicle to partial absence. - Multiple unerupted supernumerary teeth is also present in this condition.
  11. 11. Cleidocranial dysplasia
  12. 12. B)Congenitally Missing Teeth Congenital absence of teeth results from disturbances during the intial stages of tooth formation . Anodontia – Total absence of teeth Oligodontia - Absence of many but not all the teeth. Oligodontia showed a tendency for delayed tooth formation*. (* Angle orthodontist vol 63 No:1,1993).
  13. 13. Ectodermal dysplasia  Ectodermal dysplasia is characterized by soft , smooth , thin and dry skin with partial or complete absence of sweat glands.  The sebaceous glands and hair follicles are absence.  The bridge of the nose are depressed.  This also manifested with anodontia or Oligodontia.
  14. 14. Frequency of absence(Missing) Maxillary and Mandibular third molars Maxillary lateral incisors Mandibular second premolar Mandibular incisors Maxillary second premolar Congenitally missing teeth can lead to spacing between teeth and aberrant swallowing pattern.
  15. 15. Congenitally Misssing Lateral Incisors
  16. 16.
  17. 17. 2)Anomalies of Tooth Size : A tooth size is determined by heredity . Anomalies of Tooth Size Microdontia Macrodontia
  18. 18. True generalized microdontia is usually associated with pituitary dwarfism. True generalized macrodontia is usually associated with pituitary gigantism. The most commonly localized microdontia involves the maxillary lateral incisors (peglaterals).
  19. 19. Microdontia Macrodontia
  20. 20. 3)Anomalies of Tooth Shape :  Intimately related to tooth size is tooth shape.  Abnormal shaped teeth predispose to malocclusion.  Presence of maxillary-‘Peg lateral’ incisors  spacing will often occur in the maxillary anterior segment.
  21. 21.  Abnormally large cingulum on the maxillary incisor (Talons cusp) or heavy marginal ridge can force the teeth labially and prevent the establishment of a normal overbite-overjet relationship.  Mandibular second premolar also shows great variation in shape & size. It may have an extra lingual cusp , which usually serve to increase the mesiodistal dimension of the tooth.
  22. 22.  Anomalies of shape can also occur as a result of amelogenesis imperfecta, hypoplasia, gemination, dens in dente, odontomas , fusion and congenital syphilitic aberration such as Hutchinson‘s incisors and mulberry molars.
  23. 23. Dilaceration is a condition characterized by an abnormal angulation between the crown and root of a tooth .Dilacerated teeth fails to erupt to normal level and can cause malocclusion.
  24. 24.
  25. 25. Gemination
  26. 26. Twinning
  27. 27. Fusion
  28. 28. 4) Abnormal Labial Frenum :    Abnormalities of the maxillary labial frenum are  associated with a midline diastema .  At birth frenum is attached to the alveolar ridge   with fibers running into the incisive  papilla. The teeth  erupts and as alveolar bone is deposited, the frenum  attachment migrates superiorly with  the alveolar ridge.
  29. 29. Abnormal Labial Frenum
  30. 30. Fibers may persist between the maxillary central  incisors and in the ‘V’ shaped intermaxillary suture ,  attaching to the outer layer of the periosteum and  connective tissue of the suture. Faust in Weber ,noted that diastema may be due to  other factors, the possible  causative factors :       Microdontia, Macrognathia,Super numerary teeth,Peg  laterals,Missing lateral incisors ,Habits  as thumb  sucking, tongue thrusting & midline pathologies.
  31. 31. Diastema Due to Abnormal Frenum Age                 Incidence of Diastema      6                             97%  6-7                            88% 10-11                         40% 12-18                          7%
  32. 32. 5)Premature loss of Deciduous teeth :  Deciduous teeth are the space savers for the  permanent teeth.  They also maintaining the opposing teeth at the   proper occlusal level.
  33. 33.              Deciduous cuspids are frequently shed       pre-maturely and nature provide more space to  align the permanent incisor teeth that have already  erupted.  Pre mature removal of  posterior deciduous   teeth because  of  caries  Malocclusion   unless  space  maintainers are placed.
  34. 34. Lee way Space :  In the mandibular arch combined width of the  deciduous canine, First & second deciduous molar is  on the average of 1.7 mm greater on each side than the  permanent successors.       In the maxillary  arch “lee way space” average is      0.9mm  because of the greater size of the permanent  canine, first and second pre molar teeth.     This space differential is necessary for the occlusal  adjustment and final alignment of the incisors.
  35. 35.  Pre mature loss (Extraction) of the deciduous  second molar will lead to mesial drift  of the first  permanent molar and blocking  of the erupting  second premolars.       The  early  loss of permanent teeth should be  considered just as severe a ‘Malocclusion maker’  as loss of deciduous teeth.
  36. 36. 6)Prolonged retention of deciduous teeth :  Whatever the reason for the prolonged retention of  deciduous teeth, they have  a significant impact on the  dentition.   Whichever deciduous teeth may be retained beyond  the usual eruption age of their permanent successor   is  capable of causing buccal / labial  or Palatal / Lingual  deflection.   Impacted in the maxillary arch might lead to the  permanent tooth erupting  is a cross bite,which might be  difficult to treat at a later stage.
  37. 37.    Impacted Permanent teeth are more difficult to  correct orthodontically, by  surgical exposure most        commonly impacted tooth is the maxillary canine(3rd  molars not in consideration) the reason      It’s  the last anterior tooth to erupt.     Space occupied by the deciduous canine is lesser   than the mesiodistal width of the permanent canines.              It has longer path of eruption
  38. 38. 7 )Delayed eruption of permanent teeth:  Reasons: 1.Early loss of  adjacent  primary teeth with a  consequential flaring or spacing between erupted teeth   may lead to decreased space availability for eruption of  the succedaneous  teeth. 2. Early loss of primary tooth leading to mucosal  thickening over the succedaneous tooth . 3. Early loss of the  primary tooth might cause excessive  bone deposition over the succedaneous tooth.
  39. 39.      4.  Due to hereditary in certain children teeth erupt  much later than established norms.      5.Presence of supernumerary tooth can block the  erupting permanent tooth.      6. Presence of odontomas  or other cysts and tumors  might prevent  the permanent tooth from erupting.
  40. 40. 7. Presence of deciduous root fragment that are not resorbed can block these erupting tooth or may deflect it preventing its eruption in an ideal location. 8. Presence of ankylosed deciduous teeth,these might not get resorbed causing a delay in the eruption of the permanent tooth.
  41. 41. 9. The succedaneous tooth might be congenitally missing delaying the loss of the primary tooth. 10. In certain endocrine disorders the eruption of permanent teeth might be delayed. Eg: hypothyroidism.
  42. 42. 8)Abnormal Eruptive path : 1.Tooth bud facing and/or placed or displaced from its ideal location. 2.Presence of a supernumerary tooth may divert a tooth from its eruptive path. 3. Presence of odontomas or a cyst tumour may divert it if not altogether prevent its eruption.
  43. 43. Abnormal Eruptive path(cont..) 4. Un resorbed or retained deciduous teeth might force a tooth to erupt along a path of least resistance rather than in place of the deciduous tooth. 5. Retained root fragments may deflect an erupting permanent tooth. 6.Arch length deficiencies or excess of tooth material may cause one or more teeth to deviate from their eruptive path.
  44. 44. Ectopic Eruption :  Malposition of a permanent tooth bud can lead to eruption in wrong place.This condition is called ectopic eruption.  Most likely to occur in the eruption of maxillary first molars.  Ecotopic eruption may generally be considered a manifestation of arch length deficiency.
  45. 45. 9)Ankylosis :  Ankylosis is the condition which involves the union of the root or part of a root directly to the bone, without the intervening periodontal membrane.  Ankylosis or partial ankylosis is encountered relatively frequently during the 6 to 12 year age period.
  46. 46.  Ankylosis of teeth is more commonly associated with certain infections, endocrine disorders and congenital disorders. Ex : Cleidocranial dysostosis , but there are rare occurrences.  Ankylosis may be due to past history of trauma.
  47. 47. 10)Dental caries  Dental caries which leads to the premature loss of a deciduous or permanent tooth subsequent drifting of contiguous teeth ,abnormal axial inclination,over eruption and bone loss.
  48. 48. 11)Improper dental restorations :  Due to improper dental restoration under contoured proximal restoration can lead to a significant decrease in the arch length especially in the deciduous molars.
  49. 49. Conclusion  Proper knowledge of preventive and interceptive orthodontics can definitely reduce the occurrence of malocclusion ,if not prevent them from occuring.
  50. 50. Thank you Leader in continuing dental education