Retention after orthodontic treatment: why relapse happens and how long to wear retainers

Active orthodontic treatment, whether with braces or aligners, ends on the day your teeth reach their planned position. For your body, however, this is only the halfway point: the tissues around the teeth need time to "accept" the new position. The period during which the result is held in place with retainers is called retention. If you skip this stage, the teeth gradually drift back, and this is what we call relapse.

What relapse is and why it happens

Relapse is the partial or complete loss of the achieved result: crowding, rotated teeth, gaps or an incorrect bite reappear. The reason is that the dental system does not "memorise" the new position of the teeth instantly.

• Periodontal fibres. During treatment the ligaments that hold a tooth in the bone are stretched and partly rebuilt. New fibres form slowly, while the old ones keep pulling the tooth toward its original position.
• Bone tissue. The bone around the root keeps remodelling for months after the tooth has stopped moving. Until remodelling is complete, the tooth's position remains unstable.
• Muscle balance. The tongue, lips and cheeks press on the teeth every minute. If habits such as tongue thrusting, mouth breathing or infantile swallowing persist, they push the teeth back to where they had been for years.

Who is at higher risk

Relapse is possible after any orthodontic treatment, but some starting situations call for special attention:

• severe crowding: the ligament apparatus "remembers" the original position;
• pronounced tooth rotations: fibres around a rotated tooth take especially long to recover;
• diastemas and spacing: after gaps are closed, the tissues tend to push the teeth apart again, especially between the upper central incisors;
• open, deep and cross bites;
• macroglossia, mouth breathing, bruxism;
• unerupted wisdom teeth pressing on neighbouring teeth;
• a thin gum biotype and adolescence, when the jaws are still growing.

In such cases the iOrtho orthodontist plans a longer retention period before treatment even starts and, where needed, myofunctional therapy or removal of the wisdom teeth.

Types of retainers

A fixed retainer is a thin wire bonded to the inner surface of the front teeth. It is invisible, works around the clock and does not depend on the patient's discipline. It requires careful hygiene and regular checks: if the wire comes loose from even one tooth, that tooth may start to shift.

A removable retention tray is a clear tray shaped to your dental arch that you wear at night. It holds all the teeth, including the back ones, but its effectiveness depends entirely on whether you wear it every night. A tray has a limited lifespan: once it loses elasticity, cracks or fits poorly, it is replaced.

Most often the two types are combined: the wire holds the front teeth, and the tray holds the whole arch.

How long to wear retainers

There is no universal term, but there are general guidelines. The first months after the appliances are removed are the most vulnerable period: without retention, the periodontal fibres begin pulling the teeth back within 48–72 hours. During this time the removable tray is often recommended for most of the day, and later only at night. In adults the retention period is usually at least twice as long as the active treatment, and in complex cases it becomes lifelong: the fixed retainer stays on the teeth, and the tray is worn several nights a week. The exact regimen is set by the iOrtho orthodontist based on the initial complexity of the case, the type of retainers and the risk factors.

How to recognise the onset of relapse

• a gap has appeared between the front teeth, even 1 mm;
• one incisor slightly overlaps its neighbour or has visibly rotated;
• the usual contact of the teeth when biting has changed, or biting has become tender;
• the night tray has become tighter to put on, or a gap has appeared between its edge and the teeth;
• the wire retainer has come loose, sticks out or can be felt with the tongue.

If the tray feels tight after a few missed nights but the discomfort disappears after one or two nights of wear, that is adaptation, not relapse. If the sensations persist, book a check-up.

What to do if the teeth have shifted anyway

Shifting is almost always reversible. A minor relapse is corrected with a short course of aligners, usually a few months, after which new retainers are made. The sooner you come in, the simpler and faster the correction will be. Do not try to "push" the teeth back yourself with an old tray: a deformed or tight tray can damage the teeth and gums.

After treatment is complete, come in for preventive check-ups every 6–12 months: the orthodontist will check the condition of the retainers and the stability of the result, and will notice the first signs of shifting in time.