Dental retainer: what it is, what it does and how long to wear it

1 Why can teeth move after orthodontic treatment?

After orthodontic treatment, teeth may move because the bone and supporting tissues need time to adapt to their new position. Forces generated by chewing, the tongue, the lips and facial muscles may also gradually affect alignment. This process, known as orthodontic relapse, may occur after fixed braces, Invisalign or other clear aligner treatments.

Dental retention stabilises the result achieved and reduces the risk of teeth moving back towards their previous position. For this reason, a fixed or removable dental retainer is used at the end of treatment, selected according to the movements performed, the final position of the teeth and the patient’s individual risk of relapse.

2 Fixed retainer: how does it work and when is it recommended?

A fixed retainer is a thin retention wire bonded to the inner surface of the front teeth. It maintains alignment continuously without requiring the patient to insert or remove it. It is mainly recommended when the risk of relapse is high, when spaces closed during treatment need to remain closed, or when consistent use of a removable retainer may be unreliable.

A fixed retainer may be placed on the upper arch, lower arch or both, depending on the orthodontic movements performed and the stability of the result. It is discreet, does not affect the appearance of the smile and is selected when the position of the front teeth requires continuous long-term control.

3 Clear removable retainer or Hawley retainer: what are the differences?

The clear retainer and the Hawley retainer are both removable devices used to maintain the teeth in the position achieved after orthodontic treatment, but they have different characteristics.

• Clear retainer: It is made of transparent plastic material, fits closely over the dental arch, and is barely visible during use.

• Hawley retainer: It combines an acrylic base with a front metal wire and may be more visible than the clear model.

• Adjustment: The Hawley retainer can be adjusted in some cases, while a clear retainer that is deformed or no longer fits properly is generally replaced.

The choice depends on the previous treatment, the position of the teeth, and the retention requirements.

4 How is a dental retainer made and fitted?

A dental retainer is custom-made from an intraoral scan or dental impression and fitted at the end of orthodontic treatment. A clear retention tray is produced according to the exact shape of the dental arch so that it fits closely over the teeth, while a fixed retainer is shaped and bonded to the inner surface of the front teeth. The choice of appliance depends on the treatment completed, the final tooth position and the risk of relapse.

At the fitting appointment, the orthodontist checks the fit, stability, comfort and contacts between the dental arches, ensuring that the appliance does not interfere with the bite. The patient receives instructions on how to insert, remove and manage the retainer correctly. When necessary, the final aligner may be used temporarily until the definitive retainer is ready, but only under clinical guidance.

5 How long and how many hours a day should a retainer be worn?

A removable retainer is often worn full-time during the initial phase and later only at night, while a fixed retainer works 24 hours a day because it remains bonded to the teeth. The daily wear time and overall duration depend on the treatment performed, the stability of the alignment, the dental arch involved and the individual risk of orthodontic relapse.

Dental retention may continue for many years and, in some patients, may be maintained long term. The expression “lifelong dental retention” does not necessarily mean wearing a removable retainer day and night indefinitely, but often involves continuing night-time use according to a personalized schedule. The appliance should not be discontinued or worn less frequently without professional advice, because teeth may gradually change position even after several years.

6 How should fixed and removable retainers be cleaned and stored?

A fixed retainer should be cleaned every day along the retention wire and between the teeth using a toothbrush, suitable floss or interdental brushes recommended by the orthodontist. A clear removable retainer should be washed with cool or lukewarm water, a soft toothbrush and a mild cleaning product, while a Hawley retainer requires careful cleaning of both the acrylic base and the metal wire without bending it. Hot water and abrasive products should be avoided because they may deform, scratch or damage the appliance.

A removable retainer should be taken out before eating and before drinking anything other than water. After cleaning, it should be allowed to dry and stored in its rigid, ventilated case, away from heat, impact and contamination. Poor maintenance may promote plaque build-up, unpleasant odours, deformation or loss of fit. If the appliance no longer fits correctly, moves excessively or shows signs of damage, it should be checked by the orthodontist.

7 How often should a dental retainer be replaced?

A dental retainer does not have a fixed expiry date and should be replaced when it loses its fit, becomes deformed or no longer maintains the teeth correctly. A clear retention tray tends to wear out more quickly, especially when used every night, while a Hawley retainer may last longer if it remains stable, intact and correctly fitted to the dental arch.

A fixed retention wire is not replaced at predetermined intervals, but it should be checked periodically to confirm that it remains stable, intact and securely bonded to the teeth. The physical lifespan of the appliance is not the same as the duration of retention: even when a retainer is replaced, maintenance of the alignment may continue for many years according to the orthodontist’s instructions.