Specialist article: teeth and jaws
Retainers after bracesWhat they hold and what they do not solve
Teeth do not move by themselves. A force pushes them, in the mouth above all the tongue. The retainer locks this force in, it does not resolve it. Here you will learn why teeth move despite a retainer, which side effects are rarely mentioned and why we start with the function.
Does this sound familiar?
Your braces are off, and your teeth are moving again?
What applies to you?
Tap whatever applies to you.
If several points apply, it is worth looking beyond the teeth. In our view, the forces that act on them every day usually come from the pattern with which you breathe, swallow and balance your head. This pattern can be trained.
Why do teeth move at all?Side effects of the retainerRetainer come loose, what to do?The key points at a glance
- Teeth do not move by themselves. A force acts on them, in the mouth above all from the tongue, plus from the lips and cheeks. The retainer locks this force in, it does not resolve it. It is a purely symptomatic measure.
- If the function of breathing, swallowing and head balance is trained and established, in our view the teeth have no reason to move. That is why our goal is to reduce the retainer step by step with your orthodontic practice.
- Fixed retainers frequently come loose and can move teeth despite an intact wire. The tongue probes the wire and, in our view, practises exactly the pattern that shifted the teeth. Adhesives and wires release measurable amounts of bisphenol A and metals.
- In our view, the locked-in force finds another outlet, reaching as far as the jaw joint, neck and ear. Because years lie in between, hardly anyone thinks of the retainer.
Video
Retainers: what they hold and what side effects they can have
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Fundamentals
What a retainer does: hold, not resolve
Treatment with braces or aligners is usually followed by a holding phase, known as retention.
A retainer secures the tooth position achieved by orthodontic treatment. It comes in two forms. The fixed retainer is a thin wire bonded behind the front teeth, in the lower jaw often from canine to canine. The removable retainer is a clear aligner-type splint or a plate that you wear at night or for a few hours at a time.
A retainer no longer changes anything about the teeth. It holds in place what the treatment has achieved, as long as it is in place.
It is often said that tissue and bone first have to get used to the new position. But the long-term data show that teeth still move decades later. Behind this are forces that act every day and that the retainer does not touch. That is why, in our view, it is a symptomatic measure.
with 4,377 participants were evaluated by the Cochrane Collaboration on retention. The starting point is the statement that, without retention, teeth tend to move back1
had a high risk of bias, and most were observed for less than a year. No method proved to be reliably superior; the certainty of evidence is low to very low1
Anyone who has to hold teeth in place is reckoning with a force that pushes them back.The retention phase is the profession’s answer to the fact that teeth move back without it. It does not answer where the force comes from.
The key question
Why do teeth move at all? Because a force is acting
Teeth do not move by themselves. If a tooth moves, a force is acting on it, and in the mouth this comes above all from the tongue, plus from the lips and cheeks.
Teeth are suspended resiliently in the bone, held by elastic fibres that pull back a little after a displacement. When these were severed at the neck of the tooth, relapse was lower in 320 treated patients over almost 15 years2. But the fibres do not explain why teeth still move after decades.
The second force comes from inside and outside at the same time. In 1978, the orthodontist William Proffit summarised what determines the position of the teeth. As the most important factors, he names the resting pressures of the tongue and lips and the forces in the periodontal ligament3. The tongue presses from inside, the lips and cheeks counter it from outside.
The same paper contains a sentence that is rarely quoted along with it: breathing influences how the head, jaw and tongue are held, and thereby changes this balance. In our view, this is where the chain begins that, in many people, leads all the way to relapse.
What matters is the duration, not the strength. A swallow lasts only a moment. Proffit found that the resting pressure of the lips counts more for the dimensions of the dental arch than the tongue pressure during swallowing4. Using a rabbit tooth, he showed that a force applied for a tenth of the time has hardly any effect, but one applied half of the time acts like a constant force5.
In our view, what shifts the teeth in the long term is therefore usually the position of the tongue between swallows, together with the pressure of the lips and cheeks. If the tongue lies low and forward for hours, its pressure acts in one direction. We call the physiological starting position the tongue reference position, the so-called “tongue resting posture”.
Close your eyes for a moment and notice: where is your tongue right now?
The retainer locks the force in. It does not resolve it.If you follow this logic: if the function is trained and established, in our view the teeth have no reason to move. That is why we start with the function.
Relapse
Teeth shifting after braces: relapse
Relapse after orthodontic treatment is not a rare mishap. The longest observations on this come from Seattle.
The best-known long-term observation comes from the University of Washington in Seattle. There, the research group led by orthodontist Robert Little collected treatment records over decades and measured the position of the lower front teeth before and after treatment and up to twenty years after the end of retention.
of 31 treated patients still had clinically acceptable alignment of the lower front teeth twenty years after the end of retention. No finding made it possible to predict in whom the result would hold6
were compared in a study over around four decades: treated versus untreated people with normal occlusion. After treatment, crowding increased more in the treated group7
An objection suggests itself: teeth also change with age without treatment. But that alone does not explain the finding, because the treated patients changed more, in small groups, yet clearly as a trend. If it cannot be predicted in whom the result will hold, in our view the reason lies not in the teeth themselves, but in what acts on them every day.
The treatment ends. The force behind it continues to act.What once pushed the teeth out of line does not stop when the brace is removed. The retainer absorbs this force day after day. If it weakens or comes loose, in our view the force reasserts itself in many people.
The triad
From pattern to crowding: the chain behind it
In our view, relapse does not, as a rule, begin at the teeth, but long before, with breathing, swallowing and head balance.
The pattern deviates
Mouth breathing, a low-lying tongue and altered head balance often develop early, for example through a dummy, bottle or thumb.
The body compensates
The lips, cheeks and chin take over tasks of the tongue. The nervous system stores this compensation as a preferred pattern.
Form follows
Without support from the inside, the palate and dental arch develop more narrowly, and the teeth become crowded or tilt.
The finding develops
Crowding or malocclusion is treated, and the retainer holds the result. The pattern continues to act, and in many treated patients the teeth move back.
In our view, this triadic functional circuit explains why a retainer can hold the teeth but does not resolve the relapse. It holds the shape while the pattern that formed it keeps working. You can read how closely this is connected with the jaw joint in the article on TMD, the swallowing pattern itself under Swallowing and swallowing disorders, and the consequences of open lips under Mouth breathing.
Side effects
Side effects and risks that are rarely talked about
The retainer is considered a minor routine after treatment. The specialist literature describes side effects that often get too little attention in the consultation.
With the fixed retainer, the most common problem is that it comes loose. A review of 34 studies with 3,484 participants found around 35 per cent loose bonding sites or broken wires, and 54 per cent over long observation8. The evidence is considered weak, the direction is clear.
Loose without being noticed
If only one bonding site comes loose, you often do not notice. The teeth next to it can move while the rest of the wire still holds14.
Twist and X effect
The canines tip in opposite directions, and two incisors suddenly have different inclinations11. This can also happen with a firmly attached wire13.
Roots move too
A deformed wire or one bonded under tension rotates teeth around their long axis. In severe cases, renewed treatment is needed14.
Read fairly: one review considers the fixed retainer overall to be compatible with healthy gums, while individual studies found poorer values17. For tooth decay, the Cochrane review found no difference, but explicitly calls for longer studies on side effects1. What has mainly been studied is whether the retainer holds, hardly what else it does in the mouth.
In our view, a point that no study measures weighs more heavily. The tip of the tongue is one of the most sensitive tactile organs of the body, and its reference point lies at the palatine papilla directly behind the upper incisors. A wire with bonding points behind the teeth attracts it. It probes, plays and presses against it, many times a day and often unconsciously.
The retainer holds the teeth and cements the pattern against which it holds them.The tongue works forwards on the wire against the teeth instead of broadly against the palate, and the act of swallowing is directed against the row of teeth. In our view, this is exactly the force that shifted the teeth, now practised and reinforced every day.
Removable aligner or plate
What this means for the tongue and lips
- The tongue works around the aligner. In a randomised study, both types of retainer changed sounds such as s and sh in an acoustically measurable way21
- A plate covers the palate, that is, exactly the surface against which the tongue rests in its reference position
- Whether aligners promote clenching or mouth breathing at night has not been studied. In our view, they act like a thin bite splint that covers up the pattern instead of ordering it
In studies, aligners tend to be gentler on the gums than a bonded wire, but only work if they are worn.
These side effects are no reason to panic. They are a reason for regular check-ups, even years after treatment, and for a look at the cause.
Material
Bisphenol A and metals: what adhesive and wire release
A retainer often stays in the mouth for many years. That is why it is worth taking a sober look at what it is made of.
Ironically, in December 2024 the EU Commission banned bisphenol A (BPA) in materials that come into contact with food. The basis was a 2023 re-evaluation by EFSA, which significantly lowered the tolerable daily intake22. By contrast, BPA is released in measurable amounts from orthodontic adhesives and from material for vacuum-formed aligners, including from the adhesive of a lingual retainer23.
BPA was the highest level researchers found in saliva directly after bonding a lower retainer, in 22 people. After that, the value was no longer clearly elevated24
BPA was released into artificial saliva in the laboratory by a material for vacuum-formed aligners, and 2.75 µg/g by an adhesive, each in the first three days25
for fixed retainers released metals in the laboratory over 34 days, some of them lead, nickel or molybdenum above the Australian drinking water limit26
The authors considered the BPA amounts to be small and below the guideline values at the time, that is, those before the EFSA re-evaluation, but advised reducing the release2425. Retainer wires also release nickel, more under acid and chewing load, even those described as nickel-free27. In the laboratory, only one of seven wires was damaging to cells, and only slightly26.
Damage to health from these amounts has not been demonstrated. What is released in the mouth over many years has hardly been studied. If you have a nickel allergy, ask your practice about the wire material.
Detours
Forces do not disappear, they find another outlet
Holding the teeth in place does not stop the forces behind them. They seek the path of least resistance.
This first shows in the teeth. In our view, unintended movements under an intact wire are forces taking a new route. In a study in Bonn, almost all 30 subjects showed three-dimensional changes in the retainer block just six months after bonding28. Another study found a deep fold between the lower lip and chin to be a risk factor13, which for us is an indication that the muscles are involved.
The pattern remains
The tongue, lips and cheeks keep pressing as they did before treatment, and you swallow many hundreds to a thousand times a day.
The retainer blocks
The force can no longer shift the splinted row of teeth and acts on the roots, gums and the tooth block.
The jaw compensates
In our view, load shifts to the masticatory muscles and jaw joint. Clenching and a lower jaw that searches for its centre are part of this picture.
Head and neck share the load
The lower jaw, hyoid bone and upper cervical joints are connected via muscle chains. If the position of the jaw changes, in our view head balance changes, and the neck works harder.
Complaints elsewhere
In our view, headaches, migraine, neck pain, jaw joint complaints, pressure on the ears, ear noises or dizziness can be part of this pattern in many of those affected.
Anatomically, these sites lie close together. The jaw joint sits directly in front of the ear canal. The masticatory muscles and the muscle that opens the Eustachian tube during swallowing are supplied by the same cranial nerve. In a review of studies of adults with TMD, around half reported ear noises and about four in ten dizziness29.
In the upper cervical spinal cord, nerve fibres from the face and jaw converge with those of the upper cervical vertebrae, which is why pain can move between the neck, face and head30. More on this under TMD, Migraine and cervicogenic headache, Neck pain, Tinnitus and Dizziness.
Dr. Berndsen frequently sees patients with severe pain in whom nobody thinks of the retainer. Years often lie between treatment and complaint, presumably also one reason why the connection has hardly been studied. Just because something has not been studied does not mean it is not so.
Unexplained migraine for years? Ask yourself whether a retainer could be involved.This is food for thought, not a diagnosis and not a promise. Raise the question at your orthodontic practice.
An honest assessment: that a retainer triggers such complaints has not been tested. We are describing our model, derived from anatomy and documented tooth movements. Not all complaints have this origin.
Retainer loose
Retainer loose or bent: what now?
Fixed retainers frequently come loose, often without you noticing straight away. That is no reason to worry, but a reason to act promptly.
Loose wire
A bonding point has come loose, and the wire wobbles or sticks out.
Sharp edge
The wire or leftover adhesive rubs against the tongue or lip.
A tooth feels different
A tooth seems loose, tilted or rotated, or a gap is opening.
Aligner no longer fits
The removable retainer presses noticeably or no longer sits properly.
Irritated gums
The gums around the retainer bleed or swell, and cleaning is difficult.
If you notice these signs, contact your orthodontic or dental practice promptly. Whether the retainer is re-bonded, replaced or supplemented with an aligner is decided by the practice. Until then, continue to wear a removable retainer as prescribed.
How quickly teeth move after a retainer comes loose varies greatly. Attend check-ups even years after treatment12.
Retention
Retainer for life? Why we set the goal differently
Today, it is often advised to wear the retainer for a very long time or for life. We draw a different conclusion from the same data.
In the Seattle collection of more than 600 cases, crowding of the lower front teeth continued to increase after treatment, up to the age of 20 to 40 and beyond31. With a retainer it remains more stable, in 200 of 221 treated patients for five years12, and the dental arches nevertheless became steadily shorter32. This shows what a wire achieves as long as it is in the mouth. Without it, Little answers with ten per cent after twenty years.
The retainer is a crutch. You cannot get rid of it as long as the cause continues to act.It takes over the system’s work of holding the teeth. As long as it has to do this, a function is missing that keeps the teeth in place on its own.
We therefore do not consider a lifelong retainer to be the goal. The original tooth position was adapted to a disturbed function. The treatment moved the teeth but left the function as it was. That is why the teeth push back to where the unchanged function leads them.
We recommend getting rid of the retainer in the long term, step by step and together with your orthodontic practice. In our view, the prerequisite is that the pattern that shifted the teeth changes first. Only when the tongue, lips and breathing support the position themselves does a reduction have a basis.
Retainers
- Holds the teeth mechanically in position
- Works as long as it is in place and intact
- Needs check-ups and thorough care
- Leaves the forces of tongue, lips and breathing as they are
Training the basic functions
- Addresses breathing, swallowing and head balance
- Practises lip closure, tongue reference position and nasal breathing in one sequence
- Needs time and regular repetition
- Goal: the function supports the position itself
The two are not mutually exclusive. The retainer secures the position as long as the pattern does not yet support it. Whether and when it is reduced is something you discuss with your orthodontic practice.
Research
Training against relapse? What the research shows
Whether training the tongue and lips reduces relapse is a legitimate question. The honest answer is that there are few studies on it.
The best-studied area is the open bite, in which the tongue often lies between the teeth. One analysis compared orthodontically treated patients with and without additional myofunctional training, i.e. targeted training of the tongue and lips. A review examined how robust the research on this is overall.
was the mean relapse of the open bite with additional muscle training compared with brace treatment alone. The comparison group consisted of people who had already relapsed; there was no random allocation33
met the criteria in a systematic review for evaluating myofunctional therapy as an adjunct to orthodontics. All had a high risk of bias34
The FaceFormer has not been studied with regard to relapse either. The only randomised study with the device, the Hamburg study of 45 children, measured basic functions, not tooth position. Both groups improved; with the FaceFormer, the tongue rested against the palate more often during swallowing, and lip closure was achieved more quickly35. You can find the classification of all studies under Studies and science.
Training
Training the pattern: so that the function supports the teeth
Resolving to keep your tongue up and your lips closed often only works as long as you are thinking about it. The position of the tongue and lips is a stored pattern, and it changes through repetition, not through insight. That is why our approach is to train the basic functions of breathing, swallowing and head balance in one combined sequence.
The brace works on the shape. The training works on the pattern that shapes it.Both have their place. The appliance positions the teeth, the training addresses the tongue, lips and breathing that act on them every day.
In FaceFormer training, the FaceFormer sits in the oral vestibule, behind the lips and in front of the teeth. A fixed retainer sits on the other side, behind the front teeth. The tip of your tongue rests against the reference point on the palate, you breathe through your nose, and your head is balanced upright.
In the basic exercise, you press the lip wedge together with your lips, bite down briefly with your back teeth and swallow once. The negative pressure draws the tongue up against the palate. Later, the pull exercise is added, in which you also pay attention to head balance.
- From day 1
Basic exercise
A few minutes three times a day with the FaceFormer ZERO; you increase the repetitions week by week.
- From around week 3
Pull exercise and night
The pull exercise is added, and the ZERO at night, as soon as the basic exercise is established. If you wear a retainer aligner at night, clarify with your practice how the two fit together.
- After a few weeks
Switching to the ONE
During the day, you train with the FaceFormer ONE. It is the same size and shape as the ZERO; the only difference is the material, the ONE is firmer.
- Over months
The pattern runs by itself
The exercise manual allows six to twelve months until the new patterns run without thinking, followed by maintenance training.
- With your practice
Reduce the retainer step by step
Once the pattern supports the position, you discuss with your orthodontic practice whether and how the retainer is reduced step by step, with the tooth position monitored.
Tongue up
The tip of your tongue rests at the reference point behind your upper incisors, and the back of your tongue against the palate. Check this a few times a day.
Lips gently closed
Your lips rest together without effort. If your chin tenses up while doing this, your mouth is working against your tongue instead of with it.
Breathe through your nose
Nasal breathing keeps your mouth closed and your tongue up. More on this in the article on the nasal septum. Taping your mouth shut at night is no substitute; more on this under Mouth taping.
Never remove the retainer on your own, not even after months of training. The training is also possible while wearing braces; with brackets, dental wax helps. The free FaceFormer app guides you through the basic exercises, and you can find all modules on the exercise pages. A separate plan applies to children, more under FaceFormer for children.
Questions
Frequently asked
What side effects does a retainer have?
Fixed retainers frequently come loose, in more than half of cases over long observation, often unnoticed. They can unintentionally tip or rotate teeth despite an intact wire, and more tartar collects on the wire. Removable aligners only work if they are worn. In our view, the tongue also practises a pattern on the wire that works against the teeth. In studies, adhesives and wires release small, measurable amounts of bisphenol A and metals.
Why do teeth shift again after braces?
Teeth do not move by themselves. A force acts on them, above all the resting pressure of the tongue, plus that of the lips and cheeks. In our view, these forces are connected with breathing, swallowing and head balance, and a brace does not change those. In addition, the elastic fibres of the periodontal ligament pull displaced teeth back a little.
Why do teeth shift despite a fixed retainer?
The most common reason is a loose bonding site, which can go unnoticed for a long time. But there are also movements with an intact wire, for example canines tipped in opposite directions or rotated incisors. In our view, they show that the forces of the tongue, lips and cheeks continue to act and take a different route past the wire. Have this checked promptly at your practice.
Can a retainer cause headaches, migraine or jaw problems?
This has hardly been studied, partly because years often lie between treatment and complaints. In our view, it is possible, because the retainer holds the teeth in place, but the forces behind them find another outlet, via the masticatory muscles and jaw joint up to head balance and the neck. Anyone who has suffered from unexplained migraine for years can therefore ask themselves whether a retainer is involved and raise this at their practice.
Does a retainer contain bisphenol A or nickel?
In studies, bisphenol A is released from orthodontic adhesives and some aligner materials, especially shortly after bonding and in small amounts. In the laboratory, retainer wires release nickel and other metals. Damage to health from this has not been demonstrated. If you have a nickel allergy, ask about the wire material.
Do I have to wear my retainer for life?
This is frequently recommended today, because crowding can increase after treatment up to the age of 20 to 40 and beyond, and it is unpredictable in whom. We set the goal differently: train the pattern of breathing, swallowing and head balance so that it supports the tooth position itself, and then reduce the retainer step by step with your practice.
Can I get rid of the retainer at some point if I train with the FaceFormer?
That is our goal, but no one can promise it. The training addresses the pattern that shifted the teeth. If this pattern supports the position itself, the retainer can be reduced step by step with your orthodontic practice, with the tooth position monitored. Never remove it on your own.
My retainer has come loose. What should I do?
Contact your practice promptly and do not bend the wire back. Continue to wear a removable retainer as prescribed until your appointment. In a long-term study, shifting under a fixed retainer was closely linked to loose bonding sites.
What is the difference between a fixed and a removable retainer?
The fixed retainer is a wire behind the front teeth. It holds around the clock, but frequently comes loose and makes cleaning more difficult. The removable aligner or plate is gentler on the gums, but only works if you wear it. According to the Cochrane review, no method reliably holds better.
Can I train with the FaceFormer if I have a fixed retainer?
Yes. The FaceFormer sits in the oral vestibule in front of the teeth; the fixed retainer sits behind them. Like everyone, you start with the FaceFormer ZERO. If you wear a removable retainer at night, check with your practice how to combine wearing time and night-time use.
Can I train with fixed braces, even at night?
Yes, training is also possible while you have fixed braces. If something presses or rubs on the brackets, dental wax helps. Whether and from when you also use the FaceFormer ZERO at night is something to discuss with your orthodontic practice, especially if other appliances are added at night.
Can I use the FaceFormer alongside aligners such as Invisalign or a retainer splint?
In principle, the two are not mutually exclusive. The FaceFormer addresses the pattern of breathing, swallowing and head balance; the splint changes or secures the position of the teeth. Because such splints are worn for many hours a day and often at night as well, check with your orthodontic practice how wearing and training times can be combined.
More articles from the knowledge section
Where to go next
Sources
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Get started
Ready for the training?
The free FaceFormer app guides you through the basic exercises, counts along and reminds you of your sessions. If you wish, a practice from the practitioner directory can support you.
FaceFormer ZERO + ONE
Both material hardnesses for getting started, day and night. The set for adults.
FaceFormer ZERO
The softer FaceFormer for getting started, for children and for the night.
FaceFormer ZERO Children’s Set
ZERO with hygiene box, plush bag and success book with stamp.
FaceFormer training aims to restore the physiological setting of the basic functions of breathing, swallowing and head balance, with lip closure and the tongue reference position, thereby creating the conditions under which symptoms can improve. It does not replace a medical assessment. You can find practitioners near you in the practitioner directory.
