There are many different types of orthodontic treatment, depending on the exact problem with your teeth or jaw.

You're likely to achieve good results within 18 to 24 months of starting treatment as long as you:

• maintain good oral hygiene
• wear your appliances as instructed
• follow your orthodontist's dietary advice
• wear your retainer to maintain the results

Assessment

The first stage of treatment is to assess the state of your teeth and their likely development. This usually involves taking X-rays, making plaster models, and taking photographs of your teeth.

This will give the orthodontist an idea of the treatment needed and the likely results.

Orthodontic appliances

Orthodontic treatment uses appliances to correct the position of the teeth. The four main types are:

• fixed braces – a non-removable brace made up of brackets that are glued to each tooth and linked with wires
• removable braces – usually plastic plates that cover the roof of the mouth and clip on to some teeth; they can only carry out very limited tooth movements
• functional appliances – a pair of removable plastic braces that are joined together or designed to interact together and fit on to the upper and lower teeth
• headgear – this isn't an orthodontic appliance itself, but can be used with other appliances and is usually worn at night

In more severe cases, treatment may involve fixed braces and surgery to move the jaw. This treatment is carried out in hospitals.

These treatments are outlined in more detail below, and further information can be found on the British Orthodontic Society (BOS) website.

Fixed braces

Fixed braces are the most common type of orthodontic appliance. They can be used when a number of teeth need to be corrected, or when the treatment needs to be precise to prevent problems in the future.

You'll be able to eat normally while wearing a fixed appliance. However, you should avoid certain foods and drinks, such as toffee, hard sweets and fizzy drinks, because they can damage the appliance and your teeth. Your orthodontist will be able to give you further advice.

If you're using a fixed appliance and you play a contact sport such as rugby, you should wear a gum shield to protect both your mouth and the appliance.

Fixed braces are usually made out of metal, so will be noticeable on the front of your teeth. Many private orthodontists now offer ceramic or clear plastic braces, although they are usually more expensive. Their use also depends on the particular problem and tooth position.

Removable braces

Removable braces can be used to correct minor problems, such as slightly crooked teeth. They can also be used to discourage children from sucking their thumb.

These braces should only be taken out of the mouth for cleaning or as a precaution during certain activities, such as cycling or playing a wind instrument. Your orthodontist can advise you about this.

Functional appliances

Functional appliances can be used to treat problems with the position of the upper jaw and teeth, and the lower jaw and teeth.

Most people will need to wear them all of the time. It's very important to follow your orthodontist's instructions about how and when to wear the appliance. If it's not worn correctly, the treatment will be unsuccessful.

It may be necessary to remove your functional appliance for cleaning and while you are eating.

Headgear

Headgear is used to correct the position of the back teeth or to keep them in position while the front teeth are being treated. Most people only need to wear headgear for a few hours during the evening or when they are sleeping. You will not be able to eat or drink while wearing headgear.

Other treatments

There are other types of braces available privately, such as "invisible" or lingual braces that fit on the back of the teeth. You will need to discuss them with your orthodontist to see whether they can be used for your problem. The cost of these braces is usually higher.

Retainers

Retainers are often used near the end of a course of orthodontic treatment. Retainers hold newly fixed teeth in place while the surrounding gum and bone adjusts to the new position of the teeth. Retainers can either be removable or fixed.

Under the NHS, your orthodontist is responsible for your care for 12 months after normal treatment ends. After this period, you will have to pay privately for continuing care, re-treatment, and any replacement or repair of retainers.

Your orthodontist will advise you when to wear your retainer. It's likely there will be some tooth movement if you stop wearing your retainer.

Changes in the position of your teeth can continue throughout life and are part of the normal ageing process. The only way to have permanently straight teeth is to wear a retainer on a part-time basis for life.

Removing teeth

In some cases, it may be necessary to remove a tooth to correct the position and appearance of nearby teeth. But, as a result of recent advances in orthodontic treatment, removing teeth has become much less common. 

However, if baby teeth have been extracted, there is a greater likelihood that adult teeth will need to be extracted as part of orthodontic treatment.