Etiology of Malocclusion (Graber's Classification)
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Etiology of Malocclusion (Graber's Classification)

Etiology Of Maloccusion


Etiology of Malocclusion


  • Cause or causes of malocclusion is the study
  • Recognition and elimination of the etiological factors is important so that one can prevent and correct the malocclusion and obtain a permanent result.
  • Etiological factors contribute to the variations more often than simple cause.

The Orthodontic Equation:


         ↓ act at
     ↓ on
                ↓ producing


Graber's Classification:

Graber classified the etiologic factors as local and general factors.


General Factors:


Following human traits are influenced by genes:


  • Frenum
  • Interarch variation
  • Tooth Size
  • Arch dimensions
  • Crowding
  • Spacing
  • Overjet
  • Tooth number
  • Tooth shape

Congenital Defects

Following are congenital defect causing malocclusion:


  • Cleft palate
  • Torticollis
  • Syphillis
  • Cerebral palsy
  • Cleidocranial Dysostosis



  1. Trauma
  2. German Measles
  3. Maternal diet
  4. Maternal metabolism



  1. Birth injury
  2. Cerebral palsy
  3. TMJ injury

Predisposing metabolic Climate and Disease


  • Endocrine imbalance
  • Metabolic Disturbances
  • Infectious diseases (Poliomyelitis)


Dietary problems

Abnormal pressure habits and functional aberrations


  • Abnormal sucking
  • Psychogenic aberrations- clenching/bruxism
  • Speech defects
  • Lip/nail biting
  • Tongue thrusting and sucking
  • Thumb and Finger sucking
  • Abnormal Swallowing
  • Tonsils/ adenoids
  • Respiratory abnormalities




Local Factors:

1. Anomalies of number:


  • Missing- congenital absence or loss due to accidents, caries
  • Supernumerary- teeth that are extra to the normal complement are called as supernumerary teeth.



  • Peg shaped conical
  • Barrel shaped/tuberculate
  • Supplemental
  • Odontomes

2. Abnormalities in tooth size:

  i. Macrodontia: 

  • Any teeth or tooth larger than normal for that particular tooth type
  • Result in crowding

  ii. Microdontia:

  • Teeth that appear smaller in size
  • Result in spacing

  iii. Most of these conditions show a positive family history

3. Abnormalities in tooth shape:

  • Presence of peg shaped maxillary lateral incisors-spacing and migration
  • Presence of large cingulum-prevent normal overjet and overbite

4. Abnormal labial frenum, mucosal barriers

5. Premature loss

6. Prolonged retention-lead to malocclusion

     Causes of prolong retention of deciduous teeth:


  • Absence of underlying permanent teeth
  • Endocrine disturbances (hypothyroidism)
  • Ankylosed deciduous teeth that fail for resorb
  • Nonvital deciduous teeth that do not resorb

7. Delayed eruption of permanent teeth:


  • Congenital absence
  • Presence of supernumerary teeth or pathology
  • Heavy mucosal barriers
  • Presence of deciduous root fragments.

8. Abnormal eruptive path

9. Ankylosis

10. Dental caries

11. Improper dental restorations



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