varnika ortho
TRANSCRIPT
GOOD MORNING
INSTITUTE OF DENTAL SCIENCES
DEPARTMENT OF ORTHODONTICS
SEMINAR ON
Retention & Relapse
Guided by : Submitted by: Dr. P.S.Raju
Dr. D.K. Agarwal SHRIYA JAIN [80] Dr. Preeti Bhattacharya VARNIKA [94]
Dr. Abhishek Agarwal
Dr.Ankur Gupta
RETENTION &
RELAPSE
CONTENTS INTRODUCTION DEFINITION OF RETENTION NEED FOR RETENTION DEFINITION OF RELAPSE CAUSES OF RELAPSE SCHOOL OF THOUGHTS RIEDEL’S THEOREM OF RETENTION LEGNTH OF RETENTION RETENTION PLANNING SPECIAL CONSIDERATION IN RETENTION
OF CERTAIN MALOCCLUSION RETAINERS
INTRODUCTION Any treatment is failure until the results
can be retained. In orthodontics, although the patient may
feel that treatment is complete when appliances are removed, an important stage lies ahead, that is retention of orthodontically treated tooth & maintaining the results for the lifetime of patient.
What is Retention? DEFINITION: By Joondeph & Riedel “The holding of teeth in idealistic & functional positions”. By Moyer “Maintaining newly moved teeth in position, long enough to aid in
stabilizing their correction”.
Why Retention is Necessary?
Orthodontically treatment results are potentially unstable as number of factors influence the results.
Retention is planned to prevent the relapse from occurring.
What Is Relapse?
It is the loss of any correction achieved by orthodontic treatment.
Causes of Relapse1. Failure to remove the cause of
malocclusion 2. Incorrect diagnosis & failure to properly
plan treatment 3. Lack of normal cuspal interdigitation. 4. Arch expansion, laterally &/or anteriorly5. Incorrect arch size & harmony6. Incorrect axial inclinations 7. Failure to manage rotations 8. Improper contacts9. Tooth size disharmony 10. Pressure exerted by erupting third molar
Schools Of Thought/Philosophie
s Present concepts of retention are based
basically on four schools of thought as follows
1. The Occlusion School2. The Apical Base School3. The Mandibular Incisor School4. The Musculature School
The Occlusion School In 1880, Norman Kingsley suggested
that- “The occlusion of teeth is the most
important factor in determining the stability in a new position”.
Good interdigitation always aid in stability in a new position.
The Apical Base School Hay’s Nance concluded that
1. If a stable permanent result is to be obtained following orthodontic treatment, mandibular teeth must be positioned properly in relation to the basal bone.
2. Arch length may be permanently increased only to a limited extent.
3. Excessive lingual or labial tipping should be avoided.
The Mandibular Incisor School
It was proposed by Grieve & Tweed. For reasons of stability, the mandibular
incisors must be placed upright or slightly retroclined over the basal bone.
The Musculature School It was introduced by Paul Roger. Establishing a proper muscle balance is
necessary.
NOTE: All the four philosophies are interrelated .
RIEDEL’S THEOREMS OF RETENTION
Riedel summarized all the different philosophies into ten theorems:
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 because certain amount of relapse is to be expected after even the minutest of correction.
Theorem 4 Occlusion is an important factor in
retention. Interdigitation in post-treatment is
important for stability. There should be occlusal balance &
harmonious occlusal contact during functional movements like mastication.
Theorem 5 Bone & adjacent tissues must be allowed to
recognize around of newly positioned teeth. The bone & soft tissue surrounding the recently
moved teeth require time to reorganize themselves. The soft tissue surrounding the oral cavity takes
longer time to orient itself to new position of teeth.
Theorem 6 Lower incisor must be placed upright over the basal bone. By this we achieve the most stable results.
Theorem 7 Corrections carried out during period of
growth are less likely to relapse.
Theorem 8 The farther teeth have been moved, the
less the likelihood of relapse. (Controversial)
Theorem 9 Arch form, particularly in the
mandibular arch, cannot be permanently altered by appliance therapy.
Theorem 10: “many treated malocclusions require
permanent retaining devices” given by Moyer
RALEIGH WILLIAMS proposed six treatment keys during finishing to
enhance stability of most unstable part of dental arch i.e lower anterior segment.
Raleigh williams six keys to lower retention
The incisal edge of the lower incisor should be placed on the A-P line or 1 mm in front of it. This is the optimum position for lower incisor stability
First Key
It also creates optimum balance of soft tissues (within the normal range) in the lower third of the face for all the variations in apical base differences
The lower incisor apices should be spread distally to the crowns more than is generally considered appropriate (parallel roots) and the apices of the lower lateral incisors must be spread more than those of the central incisors.
Second Key
The apex of the lower cuspid should be positioned distal to the crown.
Third Key
All four lower incisor apices must be in the same labiolingual plane.
Fourth Key
The lower cuspid root apex must be positioned slightly buccal to the crown.
Fifth Key
The lower incisors should be slenderized as needed after treatment.
Lower incisors without proximal wear have round and small contact points which are accentuated if the apices have been spread for stability.
Sixth Key
Consequently, the slightest amount of continuous mesial pressure can cause various degrees of collapse in the lower incisor segment.
Flattening lower incisior contact points create flat surface that help resist labiolingual crown displacement.
Length of Retention Period
The time table for soft tissue recovery from orthodontic treatment outlines the principle of retention against intra-arch instability.
A. Teeth require essentially full time retention
after comprehensive orthodontic treatment for the first 3 to 4 months after a fixed orthodontic appliance is removed.
For this a removable appliance can be given which is to be worn full time except during meals or a fixed appliance that is not too rigid.
B. Because of the slow response of the gingival fibres, retention should be continued for at least 12 months if the teeth were quite irregular initially but can be reduced to part time after 3 to 4 months.
After approximately 12 months, teeth should be stable & it should be possible to discontinue the retention in non growing patient.
In some patients who are not growing will require permanent retention to maintain the teeth which may be unstable due to lip, cheek & tongue pressure .
Retention Planning
Reidel has grouped malocclusion which require :
1. No Retention 2. Limited Retention 3. Permanent or Semi
permanent Retention
1. No Retention Required
A. Cross bite Anterior : When adequate overbite has
been achieved. Posterior : When axial inclination of
teeth remain reasonable after correction.B. Dentition treated with serial extractionsC. Correction achieved by retardation of
maxillary growth once the patient has completed growth
2. Limited Retention
A. Class I non-extraction cases with spacing & protrusion of maxillary incisor (until normal lip & tongue function has been achieved)
B. Class I & II extraction casesC. Early correction of rotated teeth to their normal
position before root completion D. Cases involving ectopic eruption or the presence
of supernumerary teethE. Corrected deep bitesF. Class II division 2 cases : Extended retention to
allow for muscle adaptation
3. Permanent or Semi permanent Retention
A. In many cases, to maintain existing esthetics extraction may not be done. The only way to create space in such cases is through expansion. These cases, especially in mandibular arch require permanent or semipermanent retention.
B. Cases of considerable generalized spacing C. Severe rotation or severe labiolingual
malposition D. Spacing between maxillary central incisors
with an otherwise normal occlusion
Special Consideration in Retention of Certain
Malocclusion
Retention after class II correction
Relapse toward a skeletal class II relationship must result from combination of tooth movement (forward in upper arch, backward in lower arch or both) & differential jaw growth of maxilla relative to the mandible.
Tooth movement which may occur due to local periodontal & gingival factors, could be a short term problem.
Whereas differential jaw growth is a more important long term problem
In such cases over correction of the occlusal relationship can be done.
If more than 2mm of the forward repositioning of the lower incisor has occurred during treatment , permanent retention will be required.
The relapse tendency after class II correction can be controlled by two ways :
First is to continue headgear to restrict maxillary growth in conjunction with a retainer to hold the teeth in alignment.
Other method is to use a functional appliance of activator bionator type to hold teeth & occlusal relationship.
Retention is often needed for 12 to 24 months or more in patients who had a severe skeletal problem initially.
Retention After Class III Correction
Chincap may be used to counter the continued growth tendency of mandible.
But the use of chincap is believed to increase the vertical growth of the mandible.
Mild class III cases are best retained using class III functional appliance such as reverse activator, FR 3 or class III bionator.
Severe class III cases that relapse from mandibular growth after treatment requires surgical correction after growth ceases.
At the completion of orthodontic treatment
3 years later of orthodontic treatment
Retention after Deep Bite Correction
A removable upper retainer is made with bite plate, which lower incisor will contact behind the maxillary anteriors if the bite begins to deepen.
The retainer does not separate the posterior teeth.
Retainer may be required for several years after fixed appliance, until the growth ceases.
Retention After Anterior Open Bite Correction
Relapse following correction of open bite is usually a result of molar extrusion or incisor intrusion.
Incisor intrusion may occur due to continued indulgence in habits such as thumb sucking or tongue thrusting.
Thus elimination of the associated etiologic factors would help in long term stability.
Excessive vertical growth tendencies & continued eruption of posterior may pose the risk of relapse.
In such cases corrected open bite is best maintained by high pull headgears to upper molar
or Use of posterior bite plane that stretches
the musculature & produces an intrusive force on the dentition.
Retainers
Definition “Passive Orthodontic Appliances that
help in maintaining and stabilizing the
position of a single tooth or group of
teeth to permit reorganization of the
supporting structures.”
IDEAL REQUIREMENTS OF RETAINERS
According to Graber a retaining appliance:
Should restrain each tooth in its direction of relapse.
Should permit the forces associated with functional activity to act freely on the teeth.
Should be self cleansing as possible and should easy to maintain oral hygiene.
Should be as inconspicuous as possible i.e. esthetic
Should be strong enough for day to day usage.
CLASSIFICATION OF RETAINERS
Classified as
Removable Fixed
REMOVABLE RETAINERS
Serve effectively for :
Retention against intra-arch instability
Retainers in patients with Growth Problems
Types Of Removable Appliances Used As
Retainers
I. Hawley’s Retainers.
II. Begg’s Retainer.
III. Removable Wraparound Retainers.
IV. Kesling’s Tooth Positioners.
V. Osamu’s Invisible Retainers
Hawley’s Retainer
Most common removable retainer.
Designed in the 1920’s as an active
removable appliance.
Components:
Clasps on Molar teeth
Labial Bow (from Canine to Canine)
ADVANTAGES
Palatal part : Automatically provides a
potential bite plane to control overbite.
Labial Bow : Excellent control of the
incisors.
DISADVANTAGESAfter the Extraction of First Premolars Standard Design of Hawley’s Retainer can not be used as :
It cannot Keep the extraction space closedIt can WEDGE the premolar extraction space open (as labial bow extends till there)
Lower Standard Hawley Retainer is
fragile. Also difficult to insert due to UNDERCUTS
in the molar and premolar region.
To overcome this :
Labial Bow Soldered to the buccal section of the Adam’s Clasps on the first molars bow.
Wrap Labial Bow around the entire arch, using C-clasps on second molars for retention.
Bring Labial wire from the baseplate between the lateral incisor and canine to solder a wire extension distally to control the canines.
MODIFICATIONS
Hawley’s Retainer With Long Labial Bow
Hawley’s Retainer with labial bow crossing distal to lateral incisor
Hawley’s Retainer with continuous Labial Bow soldered to clasps
Hawley's retainer labial Bow attached to c-clasps on
molars.
REMOVABLE WRAPAROUND
RETAINERS
Also known as :-
Full arch wrap around retainer keeps
every tooth in position.
This can be a disadvantage >>> as
retainer should allow tooth movement
individually, stimulating reorganization of
the PERIODONTAL LIGAMENT
‘’ Clip – on Retainer’’
INDICATED IN :
Periodontal breakdown
which requires splinting the
teeth together
A wrap around retainer of lower arch showing wire reinforcement of plastic material
More esthetic as compared to Hawley’s
Retainer.
Less comfortable than Hawley’s Retainer.
VARIANT: Canine to
Canine Clip on Retainer
Canine to Canine Clip on Retainer
Widely used in lower anterior region.
Can be used to realign irregular incisors if
mild crowding has developed after
treatment.
For Lower extraction case…..
Extend the wraparound wire distally on the lingual only to the central groove of the first molar.
It provides control of the second premolar and the extraction site.
BEGG’S RETAINER
Given by P.R. Begg .
Labial bow Extends distally posterior to
the last erupted molar to be embedded in
the acrylic base plate.
No clasp is used.
Ideal for cases where settling of occlusion
is required.
POSITIONERS AS RETAINERS
introduction Can be used as a -:
Removable retainer Continued as a retainer after serving initially
as a finishing device.
ADVANTAGES
It maintains the occlusal relationships as
intra-arch tooth positions.
DISADVANTAGES
Positioners do not retain incisor
irregularities and rotations as well as
standard retainers.
Because of its bulk, patients often have
difficulty in wearing a positioner full time
or nearly so.
KESLING’S TOOTH
POSITIONER
H.D. Kesling in 1945.
Made up of thermoplastic rubber
material.
Covers the upper and lower clinical
crowns and part of the adjacent gingiva.
OSAMU’S INVISIBLE
RETAINERS
Made of thin thermoplastic sheets.
Relatively inconspicuous.
Well accepted by all patients.
Provide retention by : material fully
covers the clinical crown and extends to
adjacent gingiva.
Spring retainer
It was designed to be used in the lower
anterior segments. It is capable of
aligning as well as retaining the corrected
alignment of these teeth.
FIXED RETAINERS
INTRODUCTION INDICATED where:
Intra-arch instability is anticipated
Prolonged retention is planned.
IMPORTANT INDICATIONS
Maintenance of lower incisor
position during late
growth
Diastema maintenance
& Generalised
Spacing
Maintenance of Pontic/ Implant Space
Keeping extraction
spaces closed in
adults
They are cemented or bonded to the teeth.
Gaining popularity due to their relative invisibility and reduced dependence on the patient for wearing.
Of two types :
1. Temporary Fixed Intra-coronal Retainers
2. Temporary Fixed Extra Coronal Retentive appliances
TEMPORARY FIXED INTRACORONAL
RETAINERS
INTRODUCTION
Materials used :
Combinations of Amalgam and/ or wire and
acrylic
or composite restorative material.
These are not usually used in day –to –
day practice.
Disadvantages
Loss of healthy tooth material.
Tends to discolor.
Potential sights of sensitivity and caries.
Maintenance of oral hygiene might get
compromised.
TEMPORARY FIXED EXTRA-CORONAL
RETENTIVE APPLIANCES
Employs :
Direct contact splinting.
Flexible Spiral Wire Retainer.
Mesh Pad Retainers.
Direct Contact Splinting
Adjacent teeth are bonded together at contact points using composite resins.
Disadvantages:
Breakage of adhesive.
less hygienic.
difficult to remove.
Lingual 3 to 3 Retainers
They can be banded or bonded.
Banded – 0.036/0.04” wire.
Bonded – 0.036” + mesh on canine
Bonded is preferred over Banded retainers.
WHY ARE BONDED RETAINERS PREFERRED
OVER BANDED?? Bonded retainers are:
Completely invisible from the front.
Reduced Caries risk, as complete adhesion to
the tooth surface.
No time gap between removal of fixed
appliance and bonding of retainer.
Reduced need for long term patient
cooperation.
Can be bonded directly or indirectly.
Flexible Spiral Wire Retainer
Two dimensions of the wire are used :
THICK WIRE -0.032’’
THIN WIRE- 0.02’’
Thin wires are more frequently used.
Thin wire is used in retainers in which all
teeth in a segment are bonded.
Advantages Economical.
Twists in the wire provide adequate retention.
Allow slight movement of teeth (functional movements only).
Generally thin (hence do not interfere with occlusion).
Can be used with other removable retainers/ appliances.
Disadvantages
Mandatory : Good Oral Hygiene.
Movement of teeth may occur if wire is
not passive.
Can interfere with occlusion in deep bite
cases.
Mesh Pad Retainers
Wire mesh pad directly bonded to lingual/
palatal aspect of teeth.
Bonded mesh retainers
FUNCTIONAL APPLIANCE
Functional Appliance as an active retainer can be used in teenagers but not in adults.
This is because simulating skeletal growth with a device does not happen in adults especially to a clinical useful extent.
An activator can be used as an active retainer. Not indicated if more than 3mm of occlusal
correction is sought(over this distance, tooth movement as a means of correction is a possibility)
An activator corrects teeth by restraining the eruption of maxillary teeth posteriorly and directing the erupting mandibular teeth anteriorly.
Important Considerations While Using Activators As
An Active Retainer The more the flexible removable
appliances are the more they become less suited for the retention part of active retention.
Hence an activator or bionator with an acrylic framework that contacts most teeth can be used.
Summary
Retainer Used
Class II Malocclusion Fixed Appliance-->>>> Activator
Class III Malocclusion (Mild Cases) Chin Cap, Reverse Activator, Fr3, Class III Bionator
Deep Bite Removable Upper Retainers
Open Bite High Pull Headgear to Upper Molars; Bite Block Appliance s/a Posterior Bite Plane
Realignment Of Irregular Incisors Spring Retainers (esp. lower anteriors)
Severe Rotations Fixed Lingual Retainers
Diastema Maintenance Bonded Lingual Retainer
Maintenance of Pontic/Implant Space Anteriorly-->Bonded Bridges using segments of braided wire to attach the pontic to the abutment tooth.Posteriorly-->Heavy Intracoronal Wire
Closed Extraction Spaces(In adults) Bonded Retainers
THANK YOU
THANK YOU