varnika ortho

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