Retention and Retention and RelapseRelapse

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RELAPSERELAPSEDefinition : It has been defined as the loss of any correction Definition : It has been defined as the loss of any correction

achieved by orthodontic treatment.achieved by orthodontic treatment.

Causes of relapse: Causes of relapse:

1.1. Periodontal ligament traction:Periodontal ligament traction:

Teeth moved orthodonticallyTeeth moved orthodontically

streching of periodontal principal fibres and the gingival streching of periodontal principal fibres and the gingival fibres encircling the teethfibres encircling the teeth

Fibres contract RELAPSEFibres contract RELAPSE

2.Due to growth related 2.Due to growth related changeschanges

Patient with skeltal problems Patient with skeltal problems associated with class 2 and class 3 associated with class 2 and class 3

continued abnormal growth pattern continued abnormal growth pattern after orthodontic therapyafter orthodontic therapy

RELAPSERELAPSE

3.Bone adaptation:3.Bone adaptation:

Teeth moved recently are surrounded Teeth moved recently are surrounded by lightly calcified osteoid bone.by lightly calcified osteoid bone.

No adequate stablisation of No adequate stablisation of teeth.teeth.

RELAPSERELAPSE

4.MUSCULAR FORCES:4.MUSCULAR FORCES:

Teeth are encapsulated in all Teeth are encapsulated in all directions by muscles.directions by muscles.

If muscular imbalance at the end of If muscular imbalance at the end of orthodontic therapy. orthodontic therapy.

RELAPSERELAPSE

5. Persistent etiology5. Persistent etiology: : Cause of malocclusion not eliminated.Cause of malocclusion not eliminated.

RELAPSERELAPSE

6.Role of occlusion:6.Role of occlusion:Presence of occlusal mannerisms. E.g. Presence of occlusal mannerisms. E.g.

clenching, nail biting,grinding. clenching, nail biting,grinding.

RELAPSERELAPSE

7.Role of third molars:7.Role of third molars:

If third molar erupt after the If third molar erupt after the orthodontic treatment .orthodontic treatment .

Exert pressure on the teeth. Exert pressure on the teeth.

Late anterior crowding .Late anterior crowding . RELAPSERELAPSE

Theories of RETENTIONTheories of RETENTION

Theorem 1Theorem 1..““Teeth that have been moved tend to Teeth that have been moved tend to

return to their former position”return to their former position”Theorem 2Theorem 2..““Elimination of the cause of Elimination of the cause of

malocclusion will prevent relapse”malocclusion will prevent relapse”Theorem 3.Theorem 3.““Malocclusion should be over corrected Malocclusion should be over corrected

as a safety factor”as a safety factor”

Theorem 4.Theorem 4.

““Proper occlusion is a potent factor in Proper occlusion is a potent factor in holding teeth in their corrected holding teeth in their corrected positions”positions”

Theorem 5Theorem 5..

““Bone adjacent the tissue must be allowed Bone adjacent the tissue must be allowed time to reorganize around newly time to reorganize around newly positioned teeth”positioned teeth”

Theorem 6.Theorem 6.

““If the lower incisors are based upright If the lower incisors are based upright over basal bone they are more likely to over basal bone they are more likely to remain in good alignment”remain in good alignment”

Theorem 7.Theorem 7.““Corrections carried out during periods of Corrections carried out during periods of

growth are less likely to relapse”growth are less likely to relapse”Theorem 8.Theorem 8.““The farther the teeth have been moved , The farther the teeth have been moved ,

the lesser is the risk of relapse”the lesser is the risk of relapse”Theorem 9.Theorem 9.““Arch form, particularly in the mandibular Arch form, particularly in the mandibular

arch, cannot be permanently altered by arch, cannot be permanently altered by appliance therapy”appliance therapy”

Theorem 10.Theorem 10.““Many treated malocclusions require Many treated malocclusions require

permanent retaining devices”permanent retaining devices”

Types of retention:Types of retention:

Retention can be three types :Retention can be three types :1.1. Natural or no retentionNatural or no retention2.2. Limited or short term retentionLimited or short term retention3.3. Prolonged or permanent retentionProlonged or permanent retention

Natural or No retention:Natural or No retention: Some of the conditions that do not Some of the conditions that do not

require any retention include :require any retention include :

Anterior cross bite Anterior cross bite Serial extraction procedureSerial extraction procedureBlocked out or highly placed canines Blocked out or highly placed canines

in class I extraction cases in class I extraction cases Posterior crossbite in patients having Posterior crossbite in patients having

steep cusps.steep cusps.Limited or short term retention:Limited or short term retention:Recommended in:Recommended in:Class I non extraction with dental Class I non extraction with dental

arches showing proclination and arches showing proclination and spacing.spacing.

Deep bitesDeep bitesClass I , class II , div 1 , div 2 cases Class I , class II , div 1 , div 2 cases

treated by extraction.treated by extraction.

Prolonged or permanent Prolonged or permanent retention:retention:

Midline diastemaMidline diastemaSevere relationsSevere relationsArch expansion achieved without Arch expansion achieved without

ensuring good occlusionensuring good occlusionCertain class 2, div 2 deep bite Certain class 2, div 2 deep bite

casescasesPatients exhibiting abnormal Patients exhibiting abnormal

musculature or tongue habits.musculature or tongue habits.Expanded arches in cleft palate Expanded arches in cleft palate

patients.patients.

Retainers are passive orthodontic Retainers are passive orthodontic appliances that help in appliances that help in maintaining and stabilizing the maintaining and stabilizing the position of teeth long enough to position of teeth long enough to permit reorganization of the permit reorganization of the supporting structures after the supporting structures after the active phase of orthodontic active phase of orthodontic therapy.therapy.

RETAINERSRETAINERS

Criteria's for a good retainer :Criteria's for a good retainer :

Should retain all teeth that have Should retain all teeth that have been moved into desired positions.been moved into desired positions.

Should permit normal functional Should permit normal functional forces to act on the dentition.forces to act on the dentition.

Should be self cleansing and should Should be self cleansing and should permit oral hygiene maintainence.permit oral hygiene maintainence.

Should be inconspicuous as possible.Should be inconspicuous as possible.

Leyin’s classification of Leyin’s classification of retainers:retainers:

1.1. TemporaryTemporary A. FixedA. Fixed - Intra-coronal- Intra-coronal -Extra-coronal-Extra-coronal B. RemovableB. Removable -Extra-coronal-Extra-coronal2. 2. A. Fixed A. Fixed - Intra-coronal- Intra-coronal -Extra-coronal-Extra-coronal B. RemovableB. Removable -Extra-coronal-Extra-coronal

Removable RetainersRemovable Retainers

1.1. Hawley’s Hawley’s applianceappliance

- Designed in 1920 - Designed in 1920 by Charles Hawley.by Charles Hawley.

Most frequently Most frequently used retainerused retainer

Consists of claps on Consists of claps on molars and a short molars and a short labial bow extending labial bow extending from canine to from canine to canine having canine having adjustment loopsadjustment loops

HAWLEY’S retainer HAWLEY’S retainer HAWLEY’S retainer with HAWLEY’S retainer with long labial bowslong labial bows

Hawley’s Retainer with Begg wrap around rt.Hawley’s Retainer with Begg wrap around rt.

labial bow solderedlabial bow soldered

with Adam's claspwith Adam's clasp

Begg retainerBegg retainer

Consists of a labial wire that extends Consists of a labial wire that extends till the last erupted molar and curves till the last erupted molar and curves around it to get embeded in acrylic around it to get embeded in acrylic that spans the palate.that spans the palate.

Advantage :Advantage :

There is no cross over wire that There is no cross over wire that extends between the canine and extends between the canine and premolar thereby eliminating the risk premolar thereby eliminating the risk of space opening.of space opening.

Clip – on retainer / spring Clip – on retainer / spring aligneraligner

This appliance is made of a wire frame This appliance is made of a wire frame work that runs labially over the work that runs labially over the incisors and then passes b/w the incisors and then passes b/w the canine and premolar and is reserved canine and premolar and is reserved to lie over the lingual surface. Both to lie over the lingual surface. Both the labial as well as lingual segments the labial as well as lingual segments are embedded in a strip of clear are embedded in a strip of clear acrylic.acrylic.

Use: To bring about corrections of Use: To bring about corrections of rotations commonly seen in lower rotations commonly seen in lower anterior region.anterior region.

Wrap around retainerWrap around retainer

Extended version of spring alignerExtended version of spring alignerConsists of wire that passes along Consists of wire that passes along

the labial as well as lingual surfaces the labial as well as lingual surfaces of all erupted teeth which is of all erupted teeth which is embedded in a strip of acrylic.embedded in a strip of acrylic.

Use : In stabilizing a periodontally Use : In stabilizing a periodontally weak dentition.weak dentition.

Kesling tooth positionerKesling tooth positioner

Made of thermoplastic rubber like Made of thermoplastic rubber like material that spans the inter – material that spans the inter – occlusal space and covers the clinical occlusal space and covers the clinical crowns of the U/L portion of teeth crowns of the U/L portion of teeth and a small portion of the gingiva.and a small portion of the gingiva.

Needs no activation at regular Needs no activation at regular intervals and is durable.intervals and is durable.

Drawbacks : - difficulty in speechDrawbacks : - difficulty in speech - risk of TMJ problems- risk of TMJ problems

Invisible retainersInvisible retainers

Fully cover the Fully cover the clinical crowns and a clinical crowns and a part of the gingival part of the gingival tissue.tissue.

Made of ultra thin Made of ultra thin transparent transparent thermoplastic sheets thermoplastic sheets using a Biostar using a Biostar machine.machine.

Esthetical and go Esthetical and go unnoticed.unnoticed.

Fixed RetainersFixed Retainers The fixed applianceThe fixed appliance Banded canine to canine retainer:Banded canine to canine retainer:

-Commonly used in lower anterior region.-Commonly used in lower anterior region.

-Canines are banded and a thick wire is -Canines are banded and a thick wire is contoured over the lingual aspects and contoured over the lingual aspects and soldered to canine bandssoldered to canine bands

Bonded lingual retainers:Bonded lingual retainers:

-Bonded on lingual aspects following anterior -Bonded on lingual aspects following anterior curvature.curvature.

-Ends are curved over the canines where it is -Ends are curved over the canines where it is bonded.bonded.

Banded and bondedBanded and bonded

Lingual bonded retainer from Lingual bonded retainer from canine to canine.canine to canine.

Band and spur retainersBand and spur retainers

Used where a single tooth Used where a single tooth has been orthodontcally has been orthodontcally treated for rotation treated for rotation correction or labiolingual correction or labiolingual displacement.displacement.

The tooth that has been The tooth that has been moved banded and spurs moved banded and spurs are soldered onto the are soldered onto the bands so as to overlap bands so as to overlap the adjacent teeth.the adjacent teeth.

Advantages of fixed retainer:Advantages of fixed retainer:Reduced need for patient corporationReduced need for patient corporationCan be used when conventional Can be used when conventional

retainers cannot provide same degree retainers cannot provide same degree of stability.of stability.

Bonded retainers are more estheticsBonded retainers are more estheticsNo tissue irritation unlike what may No tissue irritation unlike what may

been seen in tissue bearing areas of been seen in tissue bearing areas of Hawley’s retainerHawley’s retainer

Can be used for permanent and semi Can be used for permanent and semi permanent retention.permanent retention.

Do not effect speech.Do not effect speech.

Disadvantages of fixed Disadvantages of fixed retainers:retainers:

More cumbersome to insertMore cumbersome to insert Increased chair side timeIncreased chair side timeMore expensiveMore expensiveBanded variety may interfere with Banded variety may interfere with

oral hygiene maintainenceoral hygiene maintainenceMore prone to breakagesMore prone to breakagesLoss of healthy tooth materialLoss of healthy tooth materialTend to discolorTend to discolor