Retention And Relapse

Question 1

Define retention and relapse

Answer 1

Retention- holding teeth in idealistic and functional positions

Relapse- loss of any correction achieved by orthodontic treatment

Question 2

Causes of relapse

Answer 2

► 1.Failure to remove the cause of malocclusion
► 2.Incorrect diagnosis and failure to properly plan treatment
► 3.Lack of normal cuspal interdigitation
► 4.Arch expansion, laterally and/or anteriorly
► 5.Incorrect arch size and harmony
► 6.Incorrect axial inclinations
► 7.Failure to manage rotations
► 8.Improper contacts
► 9.Tooth size disharmony

Question 3

Methods of preventing relapse

Answer 3

Removable retainers
Fixed retainers
Active retainers

Question 4

Schools of thought

Answer 4

1. Occlusal school (Kingsley)- proper occlusion is key factor in determining stability of newly moved teeth
2. Apical base school (Alex Lundstorm)- intercanine and and intermolar width should be maintained
3. Mandibular incisor school-should be upright or slightly retroclined over the basal bone
4. Musculature school- functional muscle balance is necessary to ensure post treatment stability

Question 5

Riedel’s theorems of retention

Answer 5

► THEOREM 1 “Teeth that have been moved tend to return to their former positions

► THEOREM 2 “The elimination of the causes of a malocclusion should aid in the retention of its correction.”

► THEOREM 3 “Overcorrection of a malocclusion is a safety factor in retention”

► THEOREM 4 “Occlusion is an important factor in retention.”

► THEOREM 5 “Bone and adjacent tissues must be allowed to reorganize around of newly positioned teeth .“

► THEOREM 6 “Lower incisors must be placed upright over the basal bone”.

► THEOREM 7 “Corrections carried out during period of growth are less likely to relapse.”

► THEOREM 8 “The further teeth have been moved, the less the likelihood of relapse.”

► THEOREM 9 “Arch form, particularly in the mandibular arch, cannot be permanently altered by appliance therapy.”