RETENTION AND RELAPSE O.ppt

RETENTION AND RELAPSE

1. RETENTION
AND
RELAPSE
Dr. Chandrika Katti
Reader, Dept Of
Orthodontics
Navodaya Dental
College, Raichur

2. INTRODUCTION
Anytreatmentisafailureunlessthetreatment
resultscanberetained.Thefinalresults
achievedfollowingorthodontictreatment,
presentlytheemphasisisforretainingresultsnot
forjustafewyearsbutmaintainingresultsfor
thelifetimeofthepatients.

3. THETERMRETENTIONHASBEENDEFINEDAS
MAINTAINING NEWLY MOVED TEETHIN
POSITION,LONGENOUGH TOAIDIN
STABILIZINGTHEIRCORRECTION.
MOYERS
THETERMRETENTIONHASBEENDEFINEDAS
LOSSOFANYCORRECTION ACHIEVEDBY
ORTHODONTICTREATMENT.

4. Causes of relapse
Periodontal ligament traction
Growth related changes
Bone adaptation
Muscular forces
Failure to eliminate the original cause
Role of third molars
Role of occlusion

5. Periodontal ligament traction
Whenever teeth are moved orthodontically the pdl
principles fibres and gingival fibres are streatched.
These streatched fibres can contract and cause
relapse
Pdl fibres rearrange themselves quite rapidly to
new position
Pdl reorganisation 4weeks and supra alveolar
gingival fibres take 40 weeks to reorganise

6. Growth factor
Patients with skeletal problems associated with
classII, classIII, open bite, deeepbite malocclusion
may exhibit relapse due to continuatuion of
abnormal growth pattern after orthodontic
therapy.prolonged retention is indicated untill
active growth is completed.

7. BONEADAPTATION
Teeth that have been moved recently are surrounded by
lightly calcified osteiod bone. Thus the teeth are not
adequately stabilised and have a tendency to move to their
original position. The bony trabecualae are normally
arranged perpendicularly arranged to the long axis to the
tooth . But during ortho treatment they get aligned
paralled to the direction of force , during retention phase
they revert back to original arrangement

8. Schools of thought
The occlusion school of thought teeth is the most
important factor in determining the stability in a
new position (Kingsley)
Apical base school (Lundstorm)
Both intercanine & intermolar width should be
maintained during orthodontic treatment to
minimize relapse (McCauley)

9. Mandibular incisor school (Grieves &
Tweed)
Musculature school (Rojers)
Schools of thought

10. THEORIES OF RETENTION(Riedel)
Theorem 1 : Teeth that have been moved tend to return to
their former position
Theorem 2 : Elimination of the cause of malocclusion will
prevent relapse
Theorem 3 : Malocclusion should be over corrected as a
safety factor
Theorem 4 : Proper occlusion is a potent factor in holding
teeth in their corrected position.

11. Theorem 5 : Bone and adjacent tissues must be allowed time
to re organise around newly positioned teeth
Theorem 6 : If the lower incisor are placed upright over
basal bone they are more likely to remain in
good alignment
Theorem 7 : Corrections carried out during periods of
growth are less likely to relapse
Theorem 8 : The farther the teeth have been moved the lesser
is the risk of relapse

12. Theorem 9 : Arch form particularly in the mandibular arch
cannot b permanently altered by appliance
therapy
Theorem 10 : Many treated malocclusions require
permanent retaining devices (Moyers).

13. RALEIGH WILLIAMS –KEYS TO ELIMINATE
LOWER RETENTION
1. The incisal edge of the lower incisor should be
placed on the A-P line or 1mm in front of it.
2. The lower incisor apices should be spread distally
to the crowns more than is generally considered
appropriate & the apices of the lower lateral
incisors must be spread more than those of central
incisors.

14. 3. The apex of the lower cuspid should be positioned
distal to the crown
4. All 4 lower incisor apices must be in the same
labiolingual plane
5. The lower cuspid root apex must be positioned
slightly buccal to the crown apex
6. The lower incisors should be slenderized as
needed after treatment.

15. Types of retention
Natural or no retention
Short term retention
Long term retention

16. Natural retention
Anterior crossbite
Serial extraction
Blocked out or highly placed canines
Post. Crossbite.

17. Short term retention
Class I non extraction cases
Deepbites
Class I , Class II div 1 & div 2 cases treated by
extraction

18. Prolonged or permanent retention
Midline diastema
Severe rotation
Arch expansion achieved without good occlusion
Patients with abnormal muscular habits,some deep
bite cases
Expanded arches in cleft palate cases

19. Retainers
Removable retainers
Hawley’s retainer

20. Begg’s retainer

21. Kesling’s tooth positioner

22. INVISIBLE RETAINERS

23. CLIP –ON RETAINER / SPRING ALIGNER

24. Fixed retainers
LINGUAL BANDED RETAINER

25. LINGUAL BONDED
RETAINER
FIXED LINGUAL
RETAINER

26. Band & spur attachment Mesh retainer

28. Retention in class II
Over correction of occlusion
Continued use of headgear
Passive bionator
ClassIII
Class III bionator , frankel,
Deep bite
Hawleys retainer with ant. Bite plate
Open bite
Hawleys retainer with post. Bite block