What is relapse?
Orthodontic treatment moves the teeth into a new position with fixed braces or clear aligners. Even if the teeth look straight when treatment is finished, the surrounding tissues may not yet have fully adapted to the new situation. In orthodontics, the teeth moving somewhat back towards their old position over time is called relapse. Relapse does not mean the treatment has failed; it is a natural tendency of the teeth and surrounding tissues and, in most cases, can be largely limited with a proper retention plan.
Why do teeth shift back? Biological causes
Gum fibres and the periodontal ligament
Each tooth is attached to the bone by fine fibres called the periodontal ligament. Within the gum there are also elastic fibres that connect the teeth to each other and to the surrounding tissue. When a tooth is moved, these fibres are stretched and reorganised. While the periodontal ligament adapts relatively quickly, some fibres in the gum can take longer to settle into the new position. For a while these fibres may tend to pull the teeth back, as if they "remember the old position"; this effect can be more marked in rotated teeth.
Bone remodelling
During tooth movement, bone is broken down on one side of the tooth and new bone forms on the other. This remodelling is not complete as soon as treatment ends. Until the bone matures and supports the new position, the teeth may be more sensitive to outside forces.
Tongue, lips and habits
Teeth sit in a position of balance between the forces of the tongue, lip and cheek muscles. Habits such as tongue thrusting, lip sucking, nail biting, clenching or grinding can upset this balance and contribute to the teeth shifting again. If such habits are present, your orthodontist takes them into account in the retention plan; for information on tongue thrusting, see our article on the tongue thrusting habit.
The type of original problem
Some orthodontic conditions are considered more prone to relapse. For example, marked gaps between teeth, severely rotated teeth, an open bite and severe crowding may be monitored more closely after treatment. Your orthodontist assesses these risks when planning treatment.
Changes in the teeth with age
Whether or not they have had orthodontic treatment, teeth keep moving very slowly throughout life. In adulthood, mild crowding developing in the lower front teeth in particular is common. Reasons include slow growth and change of the jaws, the teeth's tendency to move forward over time, changes in gum and bone support, and chewing forces. So even if treatment ended years ago, small changes in the teeth may be noticed. This is one of the main reasons retention is thought of as a long-term habit.
The role of the retainer
A retainer helps the teeth stay in their new position after treatment has finished. A fixed retainer is a thin wire bonded to the back of the front teeth; a removable retainer is usually a clear aligner-like tray that you put in and take out. Your orthodontist decides which type is used, for how long and on what schedule. For general information see our retainer guide, for wear time see how long is a retainer worn, and for details of the retention process see retention treatment.
- A removable retainer only works while it is being worn; following the recommended wear schedule is important.
- The area around a fixed retainer should be cleaned carefully; if the wire breaks or comes loose, you may not notice it. See fixed retainer care and problems.
- If your retainer feels tight, this may be a sign that the teeth have moved a little; let your orthodontist know.
- Check-up appointments make it possible to see the condition of the appliance and any changes in the teeth early.
What should you do if you notice a shift?
- Check your retainer: If you have a removable retainer, put it in and see how it fits. If it does not fit at all, do not force it.
- Contact the clinic: The earlier a shift is noticed, the simpler the options usually are. If your retainer is broken or lost, the article what to do if you lose your retainer may help.
- Examination: Your orthodontist assesses the amount and cause of the shift; if needed, a new impression or digital scan is taken.
- Options: For small shifts, a new retainer may be enough. For more marked changes, a short clear aligner or fixed braces treatment may be planned. This decision is made after the examination; the page on minor orthodontic corrections may give you an idea.
Frequently asked questions
If I wear my retainer, will my teeth never shift?
A retainer helps reduce the risk of shifting considerably, but because teeth can move very slowly throughout life, small changes may still be seen. Regular wear and check-ups make it possible to notice these changes early.
I had treatment years ago and my teeth have shifted. Is retreatment possible?
In most cases, yes. Orthodontic treatment can also be done in adults; depending on the amount of shift, a short treatment may be planned. Your orthodontist assesses suitability at the examination.
I didn't wear my retainer for a few nights and it feels tight. What should I do?
Slight tightness may show that the teeth have moved a little. If the appliance fits, keep wearing it on the recommended schedule and let your orthodontist know. If it does not fit, do not force it and contact the clinic; see retainer problems and solutions.
In which cases is the risk of relapse higher?
Marked gaps, rotated teeth, an open bite and ongoing habits can increase the risk. Your orthodontist adjusts the retention plan according to these factors.
For questions, you can call 0312 911 60 36 or use the form on the contact page.
This page is for general information only; diagnosis and the treatment plan are determined by an examination and your orthodontist's assessment.
