Orthodontic retention

Orthodontic retention

Aging of the face

  • Braces removal and enjoying a new esthetic and functional smile is the ultimate reward for patients who spent months or years in treatment and for the orthodontist who provided it. These benefits should last a lifetime.
  • However, even if we would all like to have “perfect stability for life”, it is unrealistic.
  • It must be realized that certain changes are possible, unavoidable and even desirable over the years as other changes will happen in the face with growth and aging.
  • The whole body, and especially the face, will undergo multiple changes during a lifetime. Even if they don’t occur at the same time in all individuals, most of these changes are normal and unavoidable!
  • For instance, as we age, most people expect to see changes in their hair (greying, loss, thinning), their skin (wrinkles), their waist, eyesight, flexibility, etc. but few expect changes in their mouth, dentition and smile because they were never told it could happen.
  • These “normal” changes will happen whether the person underwent orthodontic treatment or not and cannot be blamed on orthodontics.

Aging produces unavoidable changes in the face and dentition


 

Stability… all about balance of forces!

  • Teeth are not anchored into the bone like in cement. They are part of a complex masticatory system that is dynamic rather than static. Teeth constantly respond to forces that are applied to them so there is
  • always a slight normal mobility of teeth.
  • With or without orthodontics, stability of the position of teeth depends a lot on the influence of the muscular environment that surrounds them (tongue, lips, cheeks, masticatory muscles, etc.).
  • Teeth move under the effect of forces. Any force applied long enough to the teeth can move them. It is the principle used in orthodontics to correct dental malpositions by using various appliances that apply “controlled” forces.
  • If teeth move, that means that a force is acting on them. This force can come from orthodontic appliances during treatment or various sources after treatment.
  • There are outside forces of variable intensity that cannot always be predicted or controlled and that could have an effect on the position of teeth (e.g.: facial musculature, masticatory forces, tongue and lip pressure, etc.).

  • Orthodontic retention is aimed at controlling as many forces as possible, but they cannot always be detected and cannot be all neutralized.
  • Even if the interdigitation of the teeth is good or excellent at the end of treatment, it must be remembered that teeth are constantly under the influence of numerous forces. This alone should be a good enough reason to justify wearing retainers faithfully.
  • Certain dental malpositions, mostly the most severe ones, can tend to reappear slightly. Severe rotations and overlapping of anterior lower teeth are the most frequent examples of this situation.
  • The position of teeth can change anytime throughout life. It is why most patients have to wear a retainer for a period of one year or more after their treatment to help stabilize the position of teeth and delay natural changes.
  • Any force acting on dentition can influence the position of teeth. The perioral musculature is an important factor with regard to this. Forces applied by the tongue and lips can affect orthodontic corrections.


We always try to make orthodontic corrections with the most care and we offer to monitor the results carefully. When retention is discontinued, even after several years, it is always possible, even normal, to observe a certain relapse. Sustained cooperation during the retention period can decrease these risks to a minimum. If you notice important changes in the position of your teeth after treatment, communicate with us.

Stabilization or retention period

  • The orthodontic retention phase, also called orthodontic contention, is aimed at minimizing unwanted dental movements and maintaining the corrections obtained during the initial period following the removal of the braces or other appliances used for correction.
  • Even if the most critical period is the first few months and year following the end of treatment, it is often indicated to stabilize or retain the teeth for a much longer period (many years). Certain practitioners even advocate “lifetime” retention.
  • It is important that you follow closely the instructions given to you concerning the wearing of the retainers during the retention period. Any negligence in that respect may cause undesirable changes.
  • This alone should be a good enough reason to justify wearing retainers faithfully.
  • As a rule of thumb, removable retainer wear is progressively reduced over a period of 18 to 30 months but fixed retainers can stay in the mouth for many years.
  • If, during the retention period, you notice significant dental movements or changes, tell us immediately.

Corrections can be very stable over several decades as shown on the two following cases treated by Dr Lemay (father).

Excellent stability of orthodontic corrections 35 years after the end of treatment.

 

Acceptable dental alignment, more than 45 years after the end of the orthodontic treatment. Notice the presence of wisdom teeth (third molars) that erupted. The first premolars were extracted for the orthodontic treatment

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Following braces removal, patients must wear one or more retention appliances aimed at maintaining the stability of the corrections obtained during treatment.

Retention appliances

  • To ensure optimal stability at the end of a treatment, orthodontists all use retention appliances that need to be worn as prescribed to be efficient.
  • Even if the majority of results are usually stable, there can be a certain relapse in the position of one or several teeth for reasons beyond our or your control.
  • If relapse is significant, which is not frequent, re-evaluation will be necessary to determine if additional measures must be taken to slow down the evolution or if other corrections are indicated.
  • Many types of appliances exist but the choice of the retention appliance is made by the orthodontist depending on the treated malocclusion, the results obtained, and the evaluation of the potential for relapse of corrections.

Can retention appliances correct teeth?

  • NO, these appliances are passive appliances that do not have any active components (except a few exceptions) that can move or correct teeth. They are aimed at maintaining the corrections obtained rather than correcting the position of teeth.
  • Some variations of appliances exist to make modifications in order to achieve very slight dental movements when there are slight relapses or very slight corrections to complete when the corrective appliances are removed but this could not replace corrective fixed appliances (braces, multi-bracket appliances) to correct dental malpositions.

Lower fixed retainers

Lower fixed retainer

The standard lower retainer that we use is a fixed stabilizing wire for which a few characteristics are described below:

  • The wire is placed on the tongue side of the teeth and is practically invisible.
  • It is bonded (glued) to the canines and thus cannot be removed by the patient (fixed).
  • This lower retainer can stay in the mouth many years without any problems if the patient’s oral hygiene is adequate.
  • If the retainer becomes loose or falls off, communicate with our office so that we can evaluate if it is necessary to rebond it.
  • Do not throw it out because it can often be rebonded.
  • We do not use any removable retention shells in the lower jaw like we do for the maxillary arch because the fixed wire used is usually more than sufficient to maintain teeth in place. Moreover, patients find it more uncomfortable for the tongue.
  • In certain cases where important rotation of a lower incisor was present before treatment, we can bond this tooth to the retention wire. If a lower incisor really moved, it would be possible to correct it simply by using an elastic band attached to the retention wire.

 

Upper removable retainers

Different types of upper removable retainers

The orthodontist will determine which appliance is most suited for your condition. In the upper jaw, we use two main types of removable appliances (that can be removed by patients).

  • The main one, called Essix, is a clear plastic shell covering the teeth, sometimes only the six front teeth.
  • It must be worn full time for two weeks, except for meals and brushing, then at night only for a period of at least one year.
  • If you have this type of appliance, it is possible that it will show some signs of wear or perforation with time. This is normal and will not affect the performance of the retainer.
  • If the appliance breaks or cannot be worn or you lose it, call us.
  • A variation of this appliance can cover both dental arches and is used in particular cases.

We use this appliance more frequently but it is not ideal for every case. The other type of upper retainer is a “Hawley“. This appliance:

  • Is made of acrylic, clasps on the molars and a front wire helping maintaining the appliance and teeth in place.
  • Must also be worn full time (except for meals and brushing), during 6 to 8 months.
  • Can be worn at night only after the first 6-8 months or according to the instructions we will give you.

Upper fixed retainers

It is also possible that fixed splints be bonded on the tongue side of some anterior upper teeth that presented more severe malpositions before treatment. If these retainers become loose or fall off, save them and call our office so that we can determine if they need to be rebonded. These upper fixed retainers, just like the lower ones, can be left in the mouth for many years.

Always bring your removable retainers with you when you come for check-up visits.

It must be emphasized that certain types of malocclusion represent a greater risk of relapse after orthodontic corrections. In such cases, special retainers are often used. These particular retainers can be worn over a longer period of time and they may be indicated in occlusal problems such as:

  • Severe anterior open bites (front teeth that do not touch);
  • Tongue pressure” problems (exerting excessive forche on the teeth);
  • Severe dental rotations;
  • Significant jaw size discrepancies or malpositions (these cases may even require a surgical correction);
  • Adults having significant bone or gingiva loss around the teeth.

Upper retainers can hold 2 or several teeth depending on each case.

Upper retainers can hold 2 or several teeth depending on each case.

Additional information on stability

Stability of dentition and long-term orthodontic corrections; What do we know and what does the orthodontic literature say?

Here are a few conclusions of studies about stability of orthodontic corrections several years after the end of treatment.

    • One thing is for sure, dental movements or displacements are expected as years go by, with or without an orthodontic treatment.

      Several incisors in rotation and a lateral incisor severely tilted inward. Retainer fixing the four incisors together

       

    • The origin and extent of changes during the retention period are unknown before, during and after treatment.
  • It is hard to predict for sure:
    • Which types of cases will be most stable once the treatment ends.
    • How will the dentition react once the retainers are removed.
    • Teeth having severe rotations before treatment tend to go back more to their initial position.
    • It is why several clinicians advocate wearing the retainers “for life”.
    • Stability of corrections of upper anterior teeth is better than lower teeth stability.
    • Teeth most likely to move are the lower anterior teeth.
    • It is expected that every case, treated or not, presents a decrease in mandibular width with time, which can lead to crowding.
    • Dentitions with spaces before treatment tend to have less overlapping after the retention period than those that are importantly cluttered at the beginning.
    • Orthodontic corrections can be stable several years and show changes after decades.
    • Stability for life” is more a myth and a wish than a reality.
    • Orthodontic retention slows down the unavoidable tendency to relapse but does not eliminate it.
    • The only way to ensure a certain stability of the lower anterior teeth is to wear a permanent fixed retention wire.

    And it bears repeating that it is not because fixed retention wires and/or removable appliances are used that there will not be any dental movements with time.

The influence of wisdom teeth on stability of teeth

  • Dental crowding is a normal and unavoidable phenomenon throughout the years. The age at which it will occur, the severity of crowding and where it will occur may vary from one person to another and this will happen whether an orthodontic treatment was performed or not.
  • Since the period when wisdom teeth erupt or try to erupt (end of adolescence, adulthood) is also the moment when dental crowding often appears, several people link these two phenomena together and come to the conclusion that the eruption of third molars (wisdom teeth) causes the tooth movement observed. These changes are particularly frequent in the area where the anterior lower teeth (incisors and canines) are located, but may also occur anywhere in the mouth at different degrees and during different periods.
  • Summarizing everything that has been published in the dental and scientific literature on this subject would take a very long time and would be complex to do because several theories, controversies and opinions that are more or less valid exist.

  • For this section on orthodontic retention, we will only mention that consensuses of international associations of orthodontists and maxillofacial surgeons, that have been in place for a few decades now, conclude that wisdom teeth have little or no influence on what we call “secondary crowding”, that is the kind of dental crowding that appears in adults or when growth stops.
  • Consequently, it is not justified nor is it recommended to extract wisdom teeth, impacted or not, in the only and unique goal to avoid dental crowding, tooth movement or a relapse of orthodontic corrections since wisdom teeth do not cause these movements.
  • Multi-factorial causes: Several factors contribute to secondary tooth movement (this will be the subject of another section of this site – under construction), but let’s mention that residual growth or jaw “remodeling” that occurs on a small scale throughout life is a factor that is considered as vital in order to explain tooth movement throughout the years. Other variables can contribute even more, such as periodontal problems that decrease the support provided to teeth, excessive or parafunctional forces acting on teeth (see bruxism), perioral muscles (tongue, lips, cheeks), the loss of teeth for any reason and function in general.
  • In short, any force that acts on the dentition may impact the position of teeth. Multiple origins of these forces exist, but the scientific community does not consider that wisdom teeth play an important role in this matter.
  • Orthodontic retention helps contain these forces and minimize their bad effects, but it is impossible to eliminate them completely. Wearing a retainer over a long period of time does not “guarantee” that no movement will occur with time, but it can minimize and delay these movements.
  • The question should then not be “IF” teeth will move but rather “WHEN” they will move. 🙁
  • However, there are multiple reasons to extract wisdom teeth. To learn more on this subject and on wisdom teeth.

How long will I have to wear my retainers?

  • As long as you like!
  • We recommend that you wear the removable upper appliance at least one year and often longer part time. This can vary from one person to another depending on the type of malocclusion corrected.
  • Fixed appliances (upper and lower wires) can be kept in the mouth “indefinitely” if oral hygiene is adequate.
  • Some practitioners use lower retention wires that are bonded to the 6 anterior teeth. We do not use this kind of appliance because we find that it is harder to clean and, since the glue covers the wire, it tends to wear more rapidly, which ends up with more appliance breakings. If a tooth gets loose from the wire without the patient knowing, dental plaque can accumulate and cause caries (see pictures).
  • The kind of lower wire that we prefer to use is very resistant and relatively easy to maintain. It is a very stiff wire that is only bonded to the canines with a little plate that covers the glue, making it less vulnerable to wearing (less susceptible to get loose).
  • With a good hygiene and regular check-ups to the dentist, the lingual wire can stay in the mouth for a very long time, like this wire that never got loose in 25 years!

 

(A) Twisted retention wire with glue in excess. This makes cleaning difficult and facilitates accumulation of plaque. (B) The arrows indicate 2 areas where the glue does not hold on the teeth anymore and, (C) when the wire is removed, we discover dental carie and gingival inflammation. (D) Another example of carie that developed under a retention wire.

Am I obliged to wear my retainers?

This question is frequently asked to us so we present information allowing each patient to make an informed decision concerning the retention phase following their orthodontic treatment.

  • Retention is an integral part of an orthodontic treatment. It allows maintaining the corrections obtained during the treatment as best and as long as possible. However, it is not guaranteed that the teeth will remain stable because too many uncontrollable factors influence stability of teeth.
  • Wearing retainers is not an “obligation” because we cannot demand it from patients, but it is a very strong recommendation made by the great majority of orthodontists for all patients having undergone significant corrections.
  • Fixed appliances or wires are easier to wear because they cannot be removed, but they have certain disadvantages; they must be cleaned thoroughly to avoid facilitating the accumulation of dental plaque and can be inconvenient for certain people. Their lifetime can be several years.
  • Removable appliances, like their name indicates, can be removed from the mouth, but they can be damaged and lost more easily. They also have a shorter lifetime depending on the model used.
  • Choosing to wear retainers or not is finally up to the patient who needs to decide in which measure he/she is ready to accept a certain relapse of the corrections. There are usually no problems in having slight dental displacement if the patient finds it acceptable esthetically and if function is not affected.
  • Certain types of malocclusions and dental corrections tend to relapse more so retention is more critical in these cases.
  • Some practitioners recommend wearing retainers “for life”. Although this can ensure some stability, it cannot guarantee it. Removable retainers having a shorter lifetime, they must be replaced regularly if someone accepts to wear them “for life”, which we find unrealistic. However, fixed appliances can stay in the mouth for decades if the patient wishes so and are easily replaceable if they break. If they become loose, they can often be rebonded.
  • Not wearing retainers is neither a certainty leading to teeth retrieving their initial position. It all depends on the corrections that were made and the type of malocclusion treated. Most of the time, orthodontic corrections do not only involve dental movements but dentoalveolar, skeletal (jaw) changes as well and influence perioral musculature. It is less likely that a relapse would allow all these changes to “undo” themselves and the occlusion to go back to square one, mostly if growth occurred.
  • Some consider that most patients would not need retention. However, the problem is that it is hard to identify for sure those who absolutely need it, so we do not take any chances and prescribe retainers to all patients.

In conclusion, retention is not “mandatory”, but strongly recommended and is part of the protocols of any major orthodontic treatment. The orthodontist only recommends a retention protocol to patients and it is up to the patients to decide what they wish to do! It all depends on what they wish in the long term.

My teeth are no longer moving, do I need to keep my retainers?

  • Patients who have finished their orthodontic treatment several years ago frequently ask us this question. The ultimate decision to wear, keep or remove orthodontic retainers, whether they be fixed or removable, is up to the patient even if all orthodontists recommend a certain retention protocol.
  • Most patients will stop wearing removable appliances after a while or the orthodontist will eventually give them the “permission” to stop wearing them. These appliances will wear out progressively and will become unusable one day or another anyway. The limited lifetime of most removable appliances is shorter than the lifetime of fixed appliances.
  • The fixed appliances (wires and splints) can stay properly bonded and intact in the mouth for years and they are the kind of appliances that patients sometimes ask to remove. The reasons can be varied: difficulty to clean (dental plaque and tartar easily accumulate), discomfort or irritation for the tongue (this is very rare), they believe that they do not need them anymore (after growth has stopped or when wisdom teeth) are extracted), etc.
  • As described previously, there are always forces acting on teeth throughout life and not having observed changes months or years after the end of an orthodontic treatment cannot guarantee that none will occur eventually. Some of these forces or causes explaining the main relapses occurring during the immediate period (12-18 months) following the removal of corrective appliances become less significant with time. This is the case of the effect that gingival periodontal fibers that bond teeth together can have and can contribute to rotations of teeth. However, other forces, difficult to measure and evaluate, are and will always be present: residual growth, effect of the perioral musculature, mastication forces, parafunctions (bruxism and teeth clenching), other oral habits, etc.
  • In summary, if you would not accept any changes in the position of your teeth, keep the retention wires and splints “indefinitely”, but if small movements would not bother you, they will not bother your orthodontist either, so you can have them removed. The decision is yours. If a small dental displacement does not cause any functional problems (interferences, wear, gingival recession, etc.) and does not bother the patient esthetically, it will certainly not bother your orthodontist!

I bite differently after wearing my removable appliance

  • Patients sometimes report having the sensation that their teeth “do not fit together” after wearing a retention shell for several hours. This mainly occurs in the morning after wearing the appliance during the night.
  • The removable retainer that covers the teeth (Essix shell) or has a bite plane prevents the teeth in each arch to come into contact when the mouth closes. This then acts as an occlusal splint used in the treatment of temporomandibular joints by “deprogramming” the mandible and by allowing it to move slightly, most often in a backward movement, in a new position.
  • The teeth of both jaws normally determine the position of the mandible at the end of the closing movement. This is determined by the relationship of teeth, their shape, the occlusion, etc., but if an appliance is placed between both arches, as it is the case with a retainer, this precise interdigitation of teeth is no longer possible and the mandible can take another position which is independent of teeth.
  • This change is not caused by dental displacements but rather by a new mandibular position which is usually temporary; as soon as the appliance is removed and the teeth in each arch start functioning together again, the mandible will progressively move back to its position that is dictated by the teeth and the occlusion. This can take from a few minutes to more than an hour. This is why patients may be under the impression that their “teeth do not fit together” in the morning when they remove the retainer.
  • The sensation of imbalance between the teeth and the jaws after wearing a retainer can vary from one person to another depending on their occlusion, the tension that they apply on the appliance when they wear it, the presence of bruxism and teeth clenching, etc.
  • The same phenomenon can occur with an occlusal splint which can be worn at night to help people suffering from bruxism.

Follow-up during the retention period

  • The removal of corrective appliances is an important step of an orthodontic treatment, but it does not mean that it is finished. Although the end of the corrective phase is the ultimate goal for the patients, maintaining the corrections obtained during the retention phase is as important.
  • To ensure that the corrections stay as stable as possible, a regular follow-up with the orthodontist is required for a certain period of time after the end of the treatment.
  • Control visits, a lot less frequent than during the treatment, are essential.
  • Each time you visit your general dentist, ask him (or his hygienist) to verify the integrity and solidity of the fixed retention splints or wires and ensure that they are well bonded. It is not always obvious for a patient to detect micro-fractures or the debonding of a splint on only one tooth. To learn more on broken retention appliances.
  • Frequency of visits:
    • When the corrective appliances are removed, fixed retention appliances and a removable upper clear retainer are immediately installed during this same visit. Certain special appliances, used in certain cases, take longer to make and are more complex to make in the lab and will be installed one or two weeks later.
    • A few weeks (2 or 3) after the corrective appliances are removed, we will see the patients again to take the final diagnostic material that allows us to document the results obtained during the treatment and will be used as a future reference to verify the stability of the corrections.
    • The patients are then re-evaluated after ± 3 months to verify the stability of the corrections and the integrity of the retention appliances.
    • If everything is OK and the corrections are stable, the patient may be seen again after ± 12 months and once per year afterward.
  • Depending on the patient’s age and the type of malocclusion corrected, the “official” follow-up may end after ± 2 years for the adult patients having finished growing, but may still last for several years for those whose growth is still active.
  • During the post-treatment follow-up, recommendations will be made about the wisdom teeth and a panoramic radiograph will be taken every few years if indicated.
  • It is important to always bring your removable appliance(s) for us to verify them during the control visits.
  • Once the last recommendations are made, growth is completed and the wisdom teeth’s fate is handled, it is not necessary for the patient to be followed regularly and may come back only if needed if problems arise with his/her retention appliances (breakage, debonding, which will occur one day or another) or if he/she is worried about significant changes in his/her occlusion that occurred.
  • This retention protocol may slightly vary from one patient to another depending on their condition and may vary from one orthodontist to another.

Maintenance of retainers (plastic shells)

  • The plastic of the retention shells that we use is initially clear or transparent but it is expected that these appliances change colors with time. This can be caused by normal oxidation of the plastic or by the patient’s diet; coffee, wine, etc. can leave residues in the mouth that will discolor the appliance more rapidly. The plastic will become more opaque, darker, whiter or more yellow quite rapidly, sometimes in just a few weeks. The speed at which the appliance changes color will vary with the patient’s diet and the maintenance of the appliance.
  • Cleaning these appliances aims mostly at avoiding accumulation of plaque on the appliance. Plaque will not destroy the plastic like it attacks tooth enamel but will cause odors and unpleasant taste!
  • You can use a simple toothbrush (with or without toothpaste) and brush gently the inside and outside of the appliance with warm or cold water. Never use very hot water. Do not put your appliance in the dishwasher (we have already seen that!) and avoid putting it aside an important source of heat. This plastic is thermoformed (the heated plastic is shaped under positive pressure) and can be distorted under intense heat.
  • You can occasionally let your appliance soak in mouthwash.
  • Do not “chew” or bite the appliance like athletes chew their mouth protector because this can distort and even destroy it.
  • Once a retention shell is distorted, it cannot be repaired or reshaped and could be unrecoverable. Depending on the time elapsed since the end of treatment, the appliance may have to be replaced.

Emergencies and problems with retainers

Breaking of retainers

In case of relapse

  • It is almost certain that there will be dental displacements at different degrees (relapse) during the years following an orthodontic treatment. As explained earlier, this is not due to the orthodontic treatment but rather depends on the nature of the forces acting on stability of dentition. It is normal that the position of teeth changes throughout the years.
  • Several slight displacements have no esthetic or functional consequences but if you observe displacements that go beyond what you are ready to “accept”, call us. Sometimes, these slight movements can be neutralized in an acceptable way. In other cases, it can be relatively easy to correct a slight displacement again.
  • However, if a displacement is more important and the treatment ended a long time ago, it will be harder to correct such relapse in a simple way (depending on the nature of the displacement). Additional corrections may be necessary. In case of doubt, do not wait until relapses are too important before you consult us.
  • Simple relapses such as reopening of a space or diastema can be easily corrected whereas others, such as dental rotations necessitating obtaining space to align them or the appearance of an anterior open bite can necessitate wearing corrective appliances.

 

But results are not guaranteed for life? – “There is nothing permanent… except change”!

 

  • NO, absolutely not. In fact, as discussed in this section, we can “guarantee” you that there will be certain changes in your mouth and dental displacements throughout your life after your orthodontic treatment. This is unavoidable and even normal up to a certain point. It is only a matter of time before it happens, which can vary from one person to another depending on the type of malocclusion and several other factors. However, it is true that certain cases stay very stable years or even decades without significant changes, but these are the minority and it is hard to predict which cases they will be.
  • Whoever pretends the opposite or suggests that he/she “guarantees stability for life” should be questioned on his/her motivation of making such a statement that is not supported by any serious scientific literature.
  • So what is the purpose of retainers? Wearing retainers minimizes the chances that certain relapse movements occur more rapidly, but does not eliminate the possibility completely, no matter what others pretend. Even wearing retainers “for life” would not ensure eternal stability.

  • And if someone made you such a “promise”, this person is either badly informed or better than us!
  • The best way to summarize the myth of “permanent stability” in orthodontics is to quote an old wise man and Greek philosopher, Heraclitus of Ephesus, who lived in the 6th century B.C. and who said: “There is nothing permanent, except change.” This maxim is still as true more than 2,500 years later!

➡ To know more on the “warranties in orthodontics” and obligations of results.

 

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