RETENTION AND RELAPSE IN ORTHODONTICS

Retention
According to MOYERS :holding of teeth following orthodontic treatment in the treated position for a period of time necessary for the maintenance of the result.
According to JOANDEPH AND RIEDEL :holding of teeth in ideal esthetic and functional position


Relapse is a return towards the preexisting(pretreatment condition).
According to MOYERS :loss of any correction achieved by orthodontic treatment
According to HOROWITZ and HUXLEY :changes in the tooth position after orthodontic treatment

Rapid relapse occurs during remodelling period .
Slow relapse occurs during post retention period.

SCHOOLS OF THOUGHTS OF RELAPSE :
OCCLUSION THEORY :Occlusion is the most potent factor in determining stability of teeth in a new position.

APICAL BASE THEORY : Apical base is important for the correction of malocclusion and maintenance of a correct occlusion.
MANDIBULAR INCISAL THEORY : Mandibular incisors must be kept upright and over basal bone.

MUSCULATURE THEORY :There is a necessity of establishing proper functional balance.

BASIC THEORIES OF RETENTION:
1.Teeth that have been moved tend to return to their former positions.
2.Elimination of cause of malooclusion will prevent reoccurence.
3.Malocclusion should be over corrected a safety factor.
4.Proper occlusion is an important factor in the holding of teeth in their corrected positions.
5.Bone and adjacent tissues must be allowed to reorganise around newly positioned teeth.
6.If the lower incisors are placed upright and over basal bone ,they are more likely to be retained.
7.Correction carried out during periods of growth are less likely to relapse.
8.Farther the teeth have been moved ,less likely they will relapse.
9.Arch form ,particularly mandibular arch form cannot br permanently altered.
10.Many treated malocclusions require permanent retaining devices.

CAUSATIVE FACTORS FOR RELAPSE :
Patient's age
Third molars
Skill of the operator
Arch form
Length of retention
Tooth size
Apical base
Mandibular rotation
Abnormal Oral habits

these may be affected by
Craniofacial growth
dentofacial growth
muscle function

RALEIGH WILLIAMS KEY'S TO ELIMINATE LOWER RELAPSE :
1.Incisal edge of lower incisors should be in an anteroposterior line or 1mm in front of it.
2.all four mandibular incisors must be in the same labiolingual plane.
3.Lower incisors apices should be spread distally to the crowns
4.Lower incisors should be slendered as neede after treatment.
5.Apex of lower cuspids should be distal to the crown.
6.Apex of lower cuspid should be slightly buccal to the crown apex.

RETAINERS are the passive orthodontic appliances that help in maintaining and stabilising the position of teeth long enough to permit reorganisation of the supporting structure after the active phase of orthodontic therapy.

REMOVABLE RETAINERS
Begg's
Hawley's
Invisible
Clip on
Kesling's tooth positioner

FIXED RETAINERS
Banded canine to canine
Band and spur
Bonded Lingual