Retention and Relapse in
Orthodontics
Retention & Relapse
• Retention:
Maintaining newly moved teeth in a position long enough to aid in stabilizing correction.
-Moyer
• Relapse:
It has been defined as the loss of any correction achieved by orthodontic treatment.
-Moyer
Causes Of Relapse
• Failure to remove the cause of malocclusion.
• Incorrect diagnosis and failure to properly plan treatment.
• Lack of normal cuspal interdigitation.
• Arch expansion, laterally and/or anteriorly.
• Incorrect arch size and harmony.
• Incorrect axial inclination.
• Failure to manage rotation.
• Improper contacts.
• Tooth size disharmony.
Why Retention Needed?
Schools of Retention
•
1. The Occlusal School•
2. The Apical Base School•
3. The Mandibular Incisor School•
4. The Musculature SchoolOcclusion school of thought ( Normans Kinsley)
•
A/C to this, proper occlusion of teeth is a potent factor in maintaining the stability of the teeth.•
At the end of active orthodontic treatment there should be proper intercuspation and interdigitation.•
There should be cusp to fossa relationship between maxillary and mandibular teeth.Apical base school of thought (Axel lundstrom)
•
A/C to this, apical base is one of the most important factors in both correction of malocclusion as well as maintenance of correctoccusion.
•
Intercanine and intermolar width should not be altered to prevent relapse.•
Nance advised to increase the arch length only to a minimal extent.Mandibular incisor school of thought(Grieve and Tweed)
•
This theory postulated that the mandibular incisors should be placed upright and over the basal bone.Musculature school of thought(Roger’s)
•
Establishing proper functional muscle balance is a must to achieve stable occlusion.•
Improper muscle balance leads to relapse.THEOREMS ON RETENTION
•
There are 10 theorems of which 9 are put forward by•
Riedel and the last one by Moyer.• THEOREM 1
•
“Teeth that have been moved tend to return to their former positions”• THEOREM 2
•
“elimination of the cause of malocclusion will prevent recurrence”• THEOREM 3
“Malocclusion should be overcorrected as a safety factor”
• THEOREM 4
• “proper occlusion is a potent factor in holding teeth in their corrected positions”
• THEOREM 5
• “bone and adjacent tissues must be allowed to reorganize around newly positioned teeth”.
• THEOREM 6
• “if the lower incisors 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 teeth have been moved ,the less likelyhood of relapse.• THEOREM 9
•
“arch form particularly in the mandibular arch,cannot be altered permanently by appliance therapy”.• THEOREM 10
•
“many treated malocclusions require permanent retaining devices”.Types of Retention
•
Reidel has grouped retention planning into 3 groups:•
1. No retention required, Natural•
2. Limited or short term retention•
3. Prolonged or Permanent retentionNatural or no Retention
•
Anterior Cross bite•
Serial extraction procedures•
Posterior Cross bite with cusps having steep inclines•
Highly placed canines in Class I.Limited or short term Retention
•
Most of treated cases comes in this category•
Retention is given to allow bone and pdl tissue to adapt to new location•
Class l class ll div 1 class ll div 2 treated with extraction•
Deep bite•
Class l nonextraction treated by arch expansionPermanent Retention
Cases requiring permanent retention are:
•
1.Midline diastema.•
2.Severe rotations.•
3.Arch expansion achieved without ensuring good occlusion.•
4.Certain class II, div 2 deep bite cases.•
5.Patients with abnormal musculature or tongue habits.•
6.Expanded arches in cleft palate patientsRETAINERS
•
Retainers are passive orthodontic appliances that help in maintaining and stabilizing the position of a single tooth/teeth long enough to permit reorganization of supporting structures after the active phase of orthodontic therapy.•
Retainers can be simply classified as- 1. Removable Retainers2. Fixed Retainers
Ideal requirements of Retainers
• 1. Should restrain each tooth in its direction of relapse.
• 2. Should permit the forces associated with functional activity to act freely on the teeth, permitting them to respond in as nearly a physiologic manner as possible.
• 3. Should be self cleansing and should permit optimal oral hygiene maintenance.
• 4. Should be as inconspicuous as possible, esthetic.
• 5. Should be rigid enough to bear the rigors of day-to-day usage.
Classification of Retainers
•
Removal Retainer1. HAWLEYS Retainer 2. Begg’s retainer
3. Clip on Retainer
4. Wrap around retainer
5. Kesling Tooth positioner 6.Invisible Retainer
• Fixed Retainer
1. Band & Spur fixed
2. Bonded canine-canine 3. Banded canine-canine
Hawley’s appliance
• Designed by Charles Hawley in 1920.
• • Most frequently used retainer
• • Components:
• • Acrylic Component:
• • Acrylic base: supports all elements of the appliance.
• • Wire Component
• • Adam’s clasps: assures retention of the appliance.
• • Labial bow: provides anterior stabilization, controls the position of
• incisors that aren’t meant to move, or the loops can be adjusted for
• appliance activation.
Advantages:
• Can be used in most cases.
• Hygiene not an issue.
• Can be modified.
Disadvantages:
• Susceptible to fracture
• Requires patient compliance.
• Visible labial bow.
• Interproximal wire may cause opening of spaces.
• High incidence of breakage and loss.
Hawley’s Appliance Modifications
•
Hawley’s retainer with long labial bow -Simple modification to the original-Appliance where the labial bow has U loops on premolar distal to canine.
-This modification allows closure of spaces distal to canine.
•
Hawley’s retainer with C-clasp- Indicated in tight occlusal contacts
•
Hawley’s retainer with contoured labial bow -Labial bow is contoured to anterior teeth.-Has better control over the anterior teeth.
•
Hawley’s retainer with a Z-spring- In cases of anterior single tooth cross bites, Z-springs incorporated into Hawley’s with posterior bite planes can open the bite sufficiently to allow the incisor to advance without occlusal interference
CLIP-ON RETAINER OR SPRING REALIGNER
• Appliance made of wire framework that runs labially over the incisors and then passes between canine and premolar and is recurved to lie over lingual surface.
Both the labial as well as lingual segments are embedded in
• a strip of clear acrylic.
Used to bring about correction of rotations Less comfortable than Hawley
Not as good in overbite maintenance
Indicated in perio cases where splinting is needed
WRAP AROUND RETAINER
•
Extended version of spring aligner that•
covers all the teeth.Consists of wire that passes along the labial as well as lingual surfaces of all erupted teeth
•
which is embedded in a strip of acrylic.Use : In stabilizing a periodontally weak dentition.
Not routinely used.
Begg’s retainer
•
• Named after late P.R. Begg
• • The labial bow extends distally posterior to the last erupted molar to be embedded in the acrylic base plate.
• • Ideal for cases where settling of occlusion is required, especially in the posterior segments, as there is no wire framework crossing the occlusion.
Advantage :
• There is no cross over wire that extends between the
canine and premolar thereby eliminating the risk of space opening.
KESLING’S TOOTH POSITIONER
• Described by H.D Kesling in 1945
• Made of thermoplastic rubber like material that spans the inter –
• occlusal space and covers the clinical crowns of the U/L portion of
• teeth and a small portion of the gingiva.
Disadvantages
• 1. Bulky and difficult to wear full-time.
• 2. Difficulty in speech and risk of TMJ problems
• 3. Do not retain incisor position
• 4. Overbite increases due to limited patient wear
Invisible Retainers
• Plastic removable appliance
Made of thin thermoplastic sheets.
Advantages:
Esthetic
Well accepted by patients High strength
Material fully covers the clinical crown and extends partly on to the adjacent gingiva.
FIXED RETAINERS
• Used in the situations where intra arch instability is anticipated and
• “prolonged retention” is planned.
They are generally cemented or bonded to the teeth.
Indications:
1. Maintaining lower incisor position.
2. Following diastema closure.
3. Pontic space maintenance
4. Retaining closed extraction spaces.
5. Prevention of rotational relapse.
Advantages of Fixed Retainer:
• Do not affect speech.
• Better tolerated by patients
• Recall visits are reduced
• Reduced need for patient corporation
• Can be used when conventional retainers cannot provide same degree of stability.
• Bonded retainers are more esthetic
• No tissue irritation unlike what may been seen in tissue bearing areas of Hawley’s retainer
• Can be used for permanent and semi permanent retention.
Disadvantages of Fixed Retainers
•
More cumbersome to insert•
Increased chair side time•
More expensive•
Banded variety may interfere with oral•
Hygiene maintenance.•
More prone to breakages•
Loss of healthy tooth materialBand and spur retainer
•
Used in cases where single tooth has been orthodontically treated for rotation correction.•
Banded canine to canine retainerCanines are banded and a thick wire is contoured over the lingual aspects and soldered to the canine bands
The bands predispose to poor oral hygiene and are unaesthetic.
• Bonded Lingual Retainer
-Retainers bonded on the lingual aspect
-S.S wire is adapted lingually to follow the anterior curvature.
-Recently use of spiral wire is recommended that can be bonded to each tooth individually.
Advantages:
• • Invisible from front
• • Reduced caries risk
•
Holding Diastema Closed:• This is another indication for fixed permanent retention, especially if the diastema between the maxillary central incisors has been closed.
• A bonded section of flexible wire can be used, contoured in such a way that it lies near the cingulum to keep it away from the occlusal contact.
• Can prevent bite deepening if lower incisors erupt.
Tooth Positioner
ACTIVE RETAINERS
•
Is a contradiction in term !•
Since the device can not be actively moving teeth•
and serving as a retainer at the same time.•
this usually accomplished with a removable•
appliance that continues as a retainers after it•
has repositioned the teeth.•
The term usually reserved for two specific situations:•
1) Realignment of irregular incisors with spring retainers.•
2) Management of class II or class III relapse tendencies with modified functional appliance.Spring Retainers
• Its a variation type from Removable Wraparound
• Retainer knows also as clip-on retainer
• The major indication for this retainer is recrowding of the lower incisors which is usually caused by late mandibular growth.
• if late crowding has developed, it often necessary to reduce the
interproximal width of lower incisors so that the crown do not tip labially into an obviously unstable position.
Its not indicated as a routine procedure.
• just 0.25mm on each.
• interproximal enamel can be removed with abrasive strips or thin flame-shaped diamond stone.
• Modified Functional Appliance as Active Retainers
• When functional appliance used as retainer it known as Modified F.A.
EX: The Bionator which is a 1 piece removable appliance designed to produce a forward positioning of the mandible correcting a skeletal Class II relationship.
• A typical use for bionator as an active retainer would be a male adolescent who had slipped back 2 to 3 mm toward a Class II relationship after early correction.
•
functional appliance as an active retainer can be used in teenagers but is of no value in adults!!•
This is because differential anterioposerior growth is not necessary to correct a small occlusal discrepancy (because tooth movement isadequate) but some vertical growth is required to prevent downward and backward rotation of the mandible.
