Theorems Of Retention In Orthodontics

Theorems of Retention

Riedel had given 9 theories of retention and Moyers put forward the 10th theory which are as follows:

Theorem 1

‘Teeth that have been moved tend to return to their former Position’.

Orthodontically moved teeth have tendency to move back to their original position after orthodontic treatment.
Causes for this relapse are many and a single etiology cannot be highlighted.

Read And Learn More: Retention and Relapse in Orthodontics: Causes, Types, Functions

Theorem 2

‘Elimination of the cause of malocclusion will prevent relapse’.

Cause for malocclusion is identifid at time of diagnosis and adequate steps should be taken in treatment plan to eliminate it. Failure to remove the causes increases the relapse potential.
This theorem is applied in existing malocclusion such as thumb sucking, tongue thrusting, etc. and not in any malocclusion where cause is elusive.

Theorem 3

‘Malocclusion should be over corrected as a safety factor’.

Overcorrection is done so that after treatment the relapse which will occur can lead to normal occlusion.
It is done while treating Class 2 and Class 3 malocclusion.
Data is not available to validate the theorem.

Theorem 4

‘Proper occlusion is a potent factor in holding teeth in their corrected positions’.

Post treatment stability get increased by the good occlusion.
Orthodontist should not restrict the treatment to achieve good intercuspation when the jaws are closed but should aim at good functional occlusion.

Theorem 5

‘Bone and adjacent tissues must be allowed time to reorganize around newly positioned teeth’.

As orthodontic tooth movement occur, numerous changes occur in bone and surrounding tissues. So there is considerable time for reorganization to get complete.
Newly deposited osteoid around recently moved teeth take time to mature and offer inadequate retention.
Periodontal as well as other gingival fibers take time to mature and reorganize.

Theorem 6

‘If the lower incisors are placed upright over the basal bones they are more likely to remain in good alignment’.

When mandibular incisors are placed upright over the basal bone results are stable.
Mandibular or occlusal plane is used as a reference plane.
Treatment should be aimed at positioning the lower incisor perpendicular to mandibular plane or even retroclined.

Theorem 7

‘Corrections carried out during period of growth are less likely to relapse’.

Orthodontic treatment should be instituted at earliest possible age.
Early treatment procedures involve the growth modulation aimed at intercepting skeletal malrelations, prevent fullfldged malocclusions and compensation from occurring.
Treatment carried at active growth period is more stable allowing tissue systems to adapt well and therefore reduce relapse potential.

Theorem 8

‘The farther the teeth have been moved, the lesser is the risk of the relapse’.

As the tooth moves away from its position lesser are the chances of the tooth to come back to its original position.
Extensive tooth movement should be minimized.
There is only a little evidence to support this concept.

Theorem 9

‘Arch form, particular in the mandibular arch, cannot be permanently altered by appliance therapy’.

Alteration in the existing arch leads to increased risk of relapse.
It is mandatory to maintain the existing molar & canine width and build arches around them.

Theorem 10

‘Many treated malocclusions require permanent retaining Devices’.

This theorem was added by Moyers.
Some malocclusions require a patient to be fitd with a permanent retaining device.
This is true in cases that are not treated to achieve occlusal goals which stand for stability.

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