Dental braces (also known as orthodontic braces) are a device used in orthodontics to correct alignment of teeth and their position with regard to bite. Braces are often used to correct malocclusions such as underbites, overbites, cross bites and open bites, or crooked teeth and various other flaws of teeth and jaws, whether cosmetic or structural. Orthodontic braces are often used in conjunction with other orthodontic appliances to widen the palate or jaws, create spaces between teeth, or otherwise shape the teeth and jaws. Most orthodontic patients are children or teenagers, however, recently, more adults have been seeking orthodontic treatment.

How braces work

Teeth move through the use of force. The force applied by the archwire pushes the tooth in a particular direction and a stress is created within the periodontal ligament. The modification of the periodontal blood supply determines a biological response which leads to bone remodelling, where bone is created on one side by osteoblast cells and resorbed on the other side by osteoclasts.

Two different kinds of bone resorption are possible. Direct resorption, starting from the lining cells of the alveolar bone, and indirect or retrograde resorption, where osteoclasts start their activity in the neighbour bone marrow. Indirect resorption takes place when the periodontal ligament has become acellular (necrosis or hyalinization), for an excessive amount and duration of compressive stress. In this case the quantity of bone resorbed is larger than the quantity of newly formed bone (negative balance). Bone resorption only occurs in the compressed periodontal ligament. Another important phenomenon associated with tooth movement is bone deposition. Bone deposition occurs in the distracted periodontal ligament. Without bone deposition, the tooth will loosen and voids will occur distal to the direction of tooth movement.

A tooth will usually move about a millimeter per month during orthodontic movement, but there is high individual variability. Orthodontic mechanics can vary in efficiency, thus explaining a wide range of response to orthodontic treatment.

Procedure

Orthodontic services may be provided by any licensed dentist trained in orthodontics. In North America most orthodontic treatment is done by orthodontists , dentists specializing in diagnosis and treatment of malocclusions—malalignments of the teeth, jaws, or both. A dentist must complete 2–3 years of additional post-doctoral training to earn a specialty certificate in orthodontics. There are many general practitioners who also provide orthodontic services.

The first step is to determine if braces are suitable for the patient. The doctor consults with the patient and inspects the teeth visually. If braces are appropriate, a records appointment is set up where X-rays, moulds, and impressions are made. These records are analyzed to determine the problems and proper course of action. Typical treatment times vary from six months to six years depending on the complexity and types of problems. Orthognathic surgery may be required in extreme cases.

Teeth to be braced will have an etchant applied to help the cement bond to the surface of the tooth. A bracket will be applied with dental cement, and then cured with light until hardened. This process usually takes a few seconds per tooth. If required, orthodontic spacers may be inserted between the molars to make room for molar bands to be placed at a later date. Molar bands are required to ensure brackets will stick. Bands are also utilized when dental fillings or other dental work make securing a bracket to a tooth unfeasible.

An archwire will be threaded between the brackets and affixed with elastic or metal ligatures. Archwires in the past had to be bent, shaped, and tightened frequently to achieve the desired results. Modern orthodontics makes frequent use of nickel-titanium archwires and temperature-sensitive materials. When cold, the archwire is limp and flexible, easily threaded between brackets of any configuration. Once heated to body temperature, the archwire will stiffen and seek to retain its shape, creating constant light force on the teeth.

Elastics are used to close open bites, shift the midline, or create a stronger force to pull teeth or jaws in the desired direction. Brackets with hooks can be placed, or hooks can be created and affixed to the archwire to affix the elastic to. The placement and configuration of the elastics will depend on the course of treatment and the individual patient. Elastics are made in different diameters, sizes, and strengths.

In many cases there is insufficient space in the mouth for all the teeth to fit properly. There are two main procedures to make room in these cases. One is extraction: teeth are removed to create more space. The second is expansion: the palate or arch is made larger by using an expander. Expanders can be used with both children and adults. Since the bones of adults are already fused, expanding the palate is not possible without surgery to unfuse them. An expander can be used on an adult without surgery, but to expand the dental arch, and not the palate.

For some patients, Invisalign might be a viable alternative to braces. The Invisalign system uses a series of clear plastic trays to move teeth into their position over a length of time. This system is not recommended for more difficult cases, or for people whose last molars have yet to erupt. However, one of the disadvantages of Invisalign is that it usually requires a longer treatment time, especially because the appliance is removable, whereas conventional braces are always working because they are fixed to the patient's teeth. This usually allows for a faster treatment because the patient is not tempted to remove the appliance, as they may be with Invisalign.

Patients may need post-orthodontic surgery, such as a fiberotomy or alternatively a gum lift, to prepare their teeth for retainer use and improve the gumline contours after the braces come off.

Each month or so the braces must be tighted. This helps shift the teeth, into the correct postition. When they get tighted the orthodontist takes off the colors, and the wire is very loose. The patient gets to chose color, and then the orthodontist tightens them, This may cause some discomfort, which is normal.

Post-treatment

In order to avoid the teeth moving back to their original position, retainers may be worn once treatment with braces is complete.

Even before getting braces some people receive spacers or separators. These go on the top and bottom back molars. Patients will wear them until their banding appointment. Spacers are small blue elastics placed between your molars. They will make space for the metal molar bands that will be fitted to the patient's mouth when the wires are added.

Surgery can also follow treatment with braces.

Some patients find braces can be discomforting in the mouth, which can affect the post-treatment of patients with braces.

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