Pathologic Tooth Migration
Pathologic tooth migration refers to the tooth displacement that results when balance among the factors that maintain physiologic tooth position is disturbed by periodontal disease.
- Pathologic tooth migration occurs most frequently in the anterior region, but posterior teeth may also be affected.
- The teeth may move in any direction and migration is accompanied by mobility and rotation.
- Pathological migration in occlusal or incisal direction is called as extrusion.
- Pathologic tooth migration is important to detect in its early stages and prevent more serious involvement by eliminating the causative factors.
Pathological Migration of Tooth Pathogenesis
The two major factors play an important role in maintaining normal position of teeth:
Health and Normal Height of Periodontium
- A tooth with weakened periodontal support is able to withstand the forces and moves away from opposing force.
- It is important to understand that abnormality rests with the weakened periodontium. Forces that are acceptable to an intact periodontium become injurious when periodontals upport is reduced. Pathologic migration may continue even after a tooth no longer contacts its antagonist.
Changes in the Force Exerted on Teeth
May occur as a result of:
- Unreplaced missing teeth.
- Failure to replace first molars.
- Others.
- Unreplaced missing teeth: This leads to driftng of teeth into the spaces created by unreplaced missing teeth, driftng results from pathologic migration, in that, it does not results from destruction of periodontal tissues. However, it usually creates conditions that lead to periodontal disease and thus initial tooth movement is aggravated by loss of periodontal support.
- Failure to replace first molars:
- The second and third molars tilt resulting in decrease in vertical dimension.
- The premolars move distally and mandibular incisors tilt or drift lingually.
- Anterior overbite is increased.
- Maxillary incisors are put labially and laterally.
- Anterior teeth extrude due to disappearance of incisal apposition.
- Diastema is created by separation of anterior teeth.
- Other causes:
- Trauma from occlusion may cause a shif in tooth position either by itself or in combination with inflammatory periodontal disease. Direction of movement depends on occlusal force.
- Pressure from tongue may cause driftng of teeth with reduced periodontal support.
- In tooth support weakened by periodontal destruction, pressure from granulation tissue of periodontal pockets has been mentioned as contributing to pathologic migration.
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