After completion of orthodontic treatment, the teeth tend to slip back towards their original positions. This, if allowed to happen, is known as 'relapse'. If teeth are likely to relapse, they are referred to as 'unstable' and the part of treatment that prevents this is called 'retention'. Many orthodontists regard retention and the longterm management of stability as one of the most important and difficult parts of orthodontic care.
Certain types of dental problems such as twisted or overlapping front teeth and certain types of treatment such as arch widening or moving the lower incisors forward are more prone to relapse.
Retainers are the opposite of braces as they prevent movement rather than cause it. The main types are:
- Removable retainers consist of thin plastic in the roof of the mouth and a wire across the front teeth. Except for the first three months, they are worn just at night.
- Vacuum retainers are removable and made of a thin sheet of clear plastic moulded to fit over the upper or lower teeth.
- Fixed retainers consist of fine wires bonded to the inner surfaces of the upper or lower front teeth. They are invisible and only require inspection every year or two.
|Invisible fixed retainer behind the lower front teeth when first fitted and, in close up, in perfect condition 10 years later|
Duration of Retention
Sometimes retention is only necessary for a few months but for most young patients, upper removable night time retention lasts 18 months and lower fixed retention lasts until age 22 to 25. For some patients, particularly adults, it is necessary to recommend longterm retention to ensure continued enjoyment of the new smile.
Teeth move even without orthodontics
The teeth become more crowded and overlapping during the late teens and early twenties in people who have had no orthodontic treatment. This is so common it has to be regarded as normal. The reasons are complex but it is likely that the wisdom teeth are not the cause even though they are frequently blamed for this. In fact, the teeth tend to become more crowded throughout life.