Orthodontics is a Greek word that literally means ‘to straighten teeth’. It is a type of dental treatment that aims to improve the appearance, position and function of crooked or abnormally arranged teeth.

Orthodontics uses mechanical devices, such as a brace, over a certain period of time (usually 18 months to two years) to correct the position of the teeth.

Healthcare professionals who specialise in orthodontics are known as orthodontists. They usually work in dental surgeries or specialist hospital units.

Who needs orthodontics?

Sometimes, a child’s teeth and jaw do not develop in the normal way. The medical term for teeth that are out of position is malocclusion.

Some cases of malocclusion occur for no obvious reason. Other cases are the result of certain behaviours, such as frequent thumb sucking, or an injury to the teeth or bones of the face.

Many cases of malocclusion do not pose serious health concerns. However, if malocclusion is not corrected during the teenage years, it may affect the appearance of the teeth and the shape of the face. This could cause psychological and emotional problems, such as lack of self-confidence, anxiety and depression.

More severe cases of malocclusion can affect the functioning ability of the teeth, mouth and jaw. For example, it can make it difficult for a person to eat food; cleaning the teeth may be harder and the teeth may be vulnerable to damage.

Malocclusion is much more common than most people think. For example, a recent study carried out in England found that around a third of 12 year olds would benefit from some degree of orthodontic treatment.

See Orthodontics - why it is used for more information.

Orthodontics on the NHS

Orthodontic treatment is only available free-of-charge on the NHS for young people who:

• are under 18 years old
• have a clear clinical need for treatment

NHS orthodontic care is not usually available for adults but may be approved on a case-by-case basis if the functional needs are great (see box, left).

A rating system, known as the Index of Orthodontic Treatment Need (IOTN), is used to assess the need and eligibility of individual cases. The IOTN consists of five grades, which are outlined below.

Grade 1

Grade 1 is used to describe almost perfect teeth.

Grade 2

Grade 2 is for minor irregularities with the teeth, such as:

• slightly protruding upper teeth
• slightly irregular teeth
• the position of the upper and lower teeth is not entirely symmetrical, such as a mild overbite or underbite, but this does not interfere with the normal function of the teeth

Grade 3

Grade 3 is for more marked irregularities with the teeth that do not usually need treatment for health reasons. For example:

• upper front teeth that protrude 4mm less than normal
• the upper teeth are slightly out of position which only interferes with normal function to a minor degree (less than 2mm)
• irregularly positioned teeth that are 4mm or less out of line
• the back teeth do not touch each other when the mouth is closed (this is known as an open bite)
• the lower teeth are overlapped by the upper teeth (this is known as a deep bite), but this does not interfere with normal function

Grade 4

Grade 4 is for severe irregularities with the teeth that need treatment for health reasons. For example:

• upper front teeth that protrude more than 6mm
• the position of the upper and lower teeth is more than 2mm out of their normal location in terms of symmetry and is interfering with normal function
• lower front teeth protrude in front of the upper teeth by more than 3.5mm
• irregularly positioned teeth that are more than 4mm out of line
• deep bite that interferes with normal function

Grade 5

Grade 5 is for severe dental health problems, such as:

• when teeth are unable to come through into the mouth due to an obstruction, crowding, additional teeth or any other cause
• a large number of missing teeth
• upper front teeth that protrude by more than 9mm
• the normal development of the skull and/or jaw has been disrupted, e.g. by a cleft lip and palate (a birth defect where there is a split in the roof of the mouth, the top lip or both)

The British Orthodontic Society’s website has more information about the Index of Orthodontic Treatment Need (IOTN).

NHS treatment is available for grade 4 and grade 5 cases. Grade 3 cases are usually judged on a case-by-case basis. Treatment may be made available if the appearance of a person’s teeth is particularly unattractive.

In some parts of the country there are currently not enough trained NHS orthodontists to meet patient demand. This means that even if your child qualifies for NHS orthodontic treatment, there may be a long waiting list before treatment becomes available.

Depending on your local primary care trust (PCT), the waiting time for orthodontic treatment can range from six months to two years.

Private treatment

If you or your child is having orthodontic treatment for purely cosmetic reasons (or you do not want to wait for NHS treatment), you will have to pay for private treatment.

Private orthodontic treatment is widely available but it can be quite expensive. The British Orthodontic Society (BOS) states that fees can vary from £2,000 to £6,000, depending on the complexity of treatment and the type of appliances that are used. However, in very complex cases, the cost of treatment may be even higher.

The BOS has an online service that you can use to find orthodontic treatment in your area. You may either be referred for treatment by your  dentist or you can seek treatment directly (self-referral).

The primary goal of orthodontics is to improve the appearance and function of misaligned or crooked teeth.

Sometimes, problems that affect the normal development of teeth run in families. This suggests that there may be certain genes that you inherit from your parents which disrupt the development of your teeth and jaw. Genes are units of genetic material that control how your body and characteristics develop.

In many cases, developmental problems with a person’s teeth and jaw occur for no apparent reason. However, a person’s teeth and jaw can sometimes be damaged in an accident, such as a fall, or as a result of activities, such as thumb sucking, that persist well into childhood.

In children, crooked or abnormally arranged teeth are not usually an immediate health problem. However, these types of abnormalities may affect the later development of the child’s teeth, mouth and jaw. In severe cases, such abnormal developments can affect a child’s physical appearance as they grow older.

Reasons for treatment

Some of the most common reasons why people are referred to an orthodontist for orthodontic treatment are listed below.

• Protruding upper front teeth - one of the most common reasons for needing orthodontic treatment, particularly as the teeth may be more prone to damage during falls or contact sports.
• Crowding - people with narrow jaws often lack enough space for their teeth, resulting in crowding.
• Impacted teeth - the adult teeth come through in the wrong position.
• Asymmetrical teeth - in some people, the centre of their upper and lower teeth do not match, giving their teeth an asymmetrical or crooked appearance.
• Deep bite - the upper teeth cover the lower teeth too much.
• Reverse bite - the upper teeth bite inside the lower teeth.
• Open bite -  the upper and lower front teeth do not meet when the mouth is closed; an open bite often occurs as a result of prolonged thumb sucking.

A course of orthodontic treatment will usually only be started after a child’s adult teeth have fully developed.

For most children this will be when they are about 12 or 13 years of age. However, in some cases, problems with a child’s teeth may only become apparent when they are 15 years of age.

In some cases, a child may need to have orthodontic treatment before their adult teeth have fully developed. For example, this could be due to an underlying condition that affects the normal development of their skull, jaw or teeth, such as a cleft lip and palate.

For adults, orthodontic treatment  can begin at any age.

Oral hygiene

Orthodontists (healthcare professionals who specialise in orthodontics) will not begin a course of orthodontic treatment until the patient has achieved a good standard of oral hygiene.

The appliances that are used in orthodontics can attract pieces of food, which can make teeth brushing more difficult and increase the risk of tooth decay during treatment. If your oral hygiene is poor and you have a significant level of tooth decay, orthodontic treatment can make these problems much worse.

Maintaining a good standard of oral hygiene during orthodontic treatment will also help to prevent tooth decay.

See the Live Well section about Dental Health  for more information and advice.

Assessment

In the first stage of orthodontic treatment, an assessment of the current state of the patient's teeth and their likely development is made. This usually involves taking X-rays and making plaster models of the teeth.

After completing the assessment, the orthodontist will be able to provide more information about the type of treatment that is needed, and the likely results.

Orthodontic appliances

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

• removable appliances - which are usually plastic plates that cover the roof of the mouth and clip on to some teeth; they can be taken out and cleaned
• functional appliances - a pair of removable plastic braces that are joined together or are designed to interact together and clip on to the upper and lower teeth
• fixed appliances - a non-removable brace that is fixed to each tooth with a metal or ceramic bracket or attachment
• headgear - this is not an orthodontic appliance itself, but it is used with other appliances to add a certain type and direction of pressure

The four types of orthodontic appliances are discussed in more detail below.

Removable appliances

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

Although the appliance is easily removable, it should only be taken out of the mouth for cleaning. However, removing the appliance may also sometimes be recommended 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 relative position of the upper jaw and teeth and the lower jaw and teeth, such as a retruded lower jaw and teeth (backward movement of the lower jaw).

Most people who use functional appliances will need to wear them all of the time. It is very important to follow your orthodontist’s instructions about how and when to wear the appliance because if it is not worn correctly, the treatment will be unsuccessful.

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

Fixed appliances

Fixed appliances are the most common type of orthodontic appliance. They can be used to treat cases where a number of teeth need to be corrected, or where a high degree of precision is required to guide the development of the teeth and prevent problems in the future.

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

If you are 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.

NHS braces are usually made out of metal, so they will be noticeable on the front of your teeth. Many private orthodontists now offer ceramic or clear plastic braces that are much less noticeable. However, these types of braces are usually more expensive than the metal variety.

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 you are wearing headgear.

It is important that you follow all of your orthodontist’s instructions relating to the use of your headgear, such as how to put it on and take it off, and how to use it at night. Failure to use headgear correctly could lead to a facial injury or, more seriously, an eye injury.

Your orthodontist will be able to train you to use your headgear correctly and safely.

Other treatments

Retainers

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

Tooth removal

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

Like any type of medical treatment, orthodontic treatment carries a risk of complications as well as benefits. The best way of minimising any possible risk is to maintain a high standard of oral hygiene and always follow your orthodontist’s instructions.

Enamel decay

Each tooth is covered with a hard outer surface called enamel. A common complication in people who are having a course of orthodontics is that the enamel in one or more of their teeth begins to decay. This can happen for a number of reasons.

Orthodontic appliances can sometimes stimulate the production of saliva, which combines with small particles of food and bacteria to form a sticky film known as plaque. The plaque causes the enamel to decay. In addition, many people with appliances find it difficult to keep their teeth clean.

In more severe cases of enamel decay, the outer layer of a tooth breaks down and the inside of the tooth can become infected, resulting in toothache. If the decay is extensive, it may need to be repaired with a filling or crown. See the Health A-Z topic about Tooth decay - treatment for more information.

Reducing the risk

To reduce your risk of enamel decay, your orthodontist may recommend that you use toothpaste with high levels of fluoride or a mouthwash that contains fluoride. Fluoride is a mineral that helps to strengthen enamel.

Avoid eating foods and drinking drinks that are high in sugary or starchy carbohydrates because they will stimulate the growth of bacteria in your mouth. Examples of sugary or starchy carbohydrates include:

• fizzy drinks
• coffee and tea with sugar added
• chocolate
• sweets
• cakes
• crisps
• biscuits
• white bread

Healthier alternatives include:

• cheese
• brown bread
• pasta
• rice
• potatoes
• leafy green vegetables
• eggs

See the Health A-Z topic about Tooth decay - prevention  for more information and advice.

Following your orthodontist’s instructions is the most important factor in determining the outcome of your orthodontic treatment.

If you maintain good oral hygiene, wear your appliances as instructed and follow your orthodontist's dietary advice, you are likely to achieve good results, usually within 18 to 24 months of starting treatment.

However, if you neglect your oral hygiene, do not wear your orthodontic appliance as instructed, and ignore the advice about what foods to avoid, you are likely to achieve poor results or, even worse, your teeth may end up in a worse state than before your treatment began.