Some people have naturally straight teeth that fit together. But if you have problems with your bite or the spacing of your teeth, you may need orthodontic care. Orthodontia is the branch of dentistry that deals with abnormalities of the teeth and jaw.

Orthodontic care involves the use of devices, such as braces, to

• Straighten teeth
• Correct problems with bite
• Close gaps between teeth
• Align lips and teeth properly

Most people who receive orthodontic care are kids, but adults get braces, too. In young children, orthodontic treatment may guide proper jaw growth. This can help permanent teeth to come in properly. Straight permanent teeth can help prevent tooth problems later on.

A dental specialty concerned with the prevention and correction of dental and oral anomalies (malocclusion).

Your teeth are made of a hard, bonelike material. There are four parts:

• Enamel, your tooth's hard surface
• Dentin, the hard yellow part under the enamel
• Cementum, the hard tissue that covers the root and keeps your teeth in place
• Pulp, the soft connective tissue in the center of your tooth. It contains nerves and blood vessels.

You need your teeth for many activities that you may take for granted. These include eating, speaking and even smiling.

• Teeth that are crooked or not arranged properly can lead to a variety of dental health problems.
• Orthodontics is a type of dentistry that improves the arrangement of teeth and jaw.
• Speak to an oral health professional –if you are worried about how you or your child’s teeth are.

Teeth of the upper and lower jaw should fit neatly together. When they don’t, it can increase the risk of tooth decay and gum disease. Orthodontics is an area of dentistry that diagnoses and improves the arrangement of the teeth and jaw using devices such as braces and plates.

Why orthodontic treatment might be needed

Crooked, crowded and overlapping teeth can cause a range of problems, including:

• tooth decay and gum disease – teeth that are very close together can be harder to clean properly. A build-up of plaque can lead to tooth decay and gum disease
• injury to the gum – if a tooth doesn’t meet with its partner on the opposite jaw properly, it may dig into the gum and cause damage
• it may be difficult to eat or chew properly, or affect your ability to speak properly, swallow or dries out your mouth.
• teeth that stick out may be more likely to be injured or traumatised during sports or in a fall.
• wear and tear – if teeth don’t come together properly the action of chewing can wear them down unevenly
• self-confidence – teeth problems can make people feel embarrassed and they may not feel comfortable to smile.

Treatment planning

Teeth can be successfully repositioned through the introduction of moderate and sustained mechanical forces in the mouth, sometimes in combination with surgery. An orthodontic treatment aims to improve the function and/or aesthetics of the mouth by realigning the teeth.

The planning of orthodontic treatment involves a precise characterization of the structure of the oral structure, consideration of the potential for change which can be strongly influenced by age and health condition, and the determination of the precise goal of the treatment. The planning phase can be challenging in its technical aspects. It requires a profound understanding of the mechanical forces involved in mastication and of the responses of the teeth, ligaments and bones to the added mechanical forces. Determining the origin of a malocclusion may not be easy, but it may be crucial for successful realignment and retention of the teeth in the new position.

The ethical aspects of the planning phase can also be challenging. The borderline between normal variation and malocclusion is not clearly delimited from either functional or aesthetical points of view. The plan should consider the patient’s age, diet, feeding habits, health condition, and need or desire for aesthetic modification. Similarly, the final alignment pursued with the treatment and how closely it needs to be matched are not absolutely defined and need to be decided in agreement with the patient.

Diagnosis

The diagnosis most commonly involves a detailed cephalometric analysis combined with careful analysis of a cast of the dentition, usually obtained through alginate impressions. The cast can be digitized and allow for tridimensional analysis in the computer.

The structure of the skull is analyzed with focus on the size and position of the jaw bones. The position and tilt of each tooth, erupted or developing is taken into account and each aspect of malocclusion is identified.

Treatment

Functional appliances

Malocclusions involving the structure of the jaws in children are usually treated with facial growth modification through the use of orthopedic devices. A variety of devices called functional appliances is available to address malocclusions. These appliances can be fixed (ex: Herbst appliance) or removable (chin cup, face mask, head gear) and they apply forces the the jaws that modify the growth of the bones, altering their final length and position.

In adults, orthognatic surgery may be required in combination with orthodontic treatment. For instance, a segment of bone may be surgically removed from the mandible of an adult with mandibular prognathism. The bone is exposed through an incision in the gums to leave no externally visible scars. The mandible is then shifted and the cut ends are held against each other by a small plate and screws as the mandible heals.

Space for the teeth on the arch can be managed with or without the extraction of permanent teeth. The discussion of the advantages and disadvantages of each approach has been controversial, and research has failed to provide evidence of a clear advantage to either approach in the function, aesthetics or stability of the final result of the treatment.

Braces

The teeth can be aligned through the use of fixed appliances (braces) or removable devices (clear aligners). Braces became popular during the 20th century, especially after 1970, when it became feasible to hold small brackets against the teeth using removable adhesives. The treatment involves the attachment of one bracket to the surface of each tooth and the installation of an archwire that goes through all brackets in the arch, connecting them. A different shape of bracket is designed for each tooth in the dentition. Arch wires vary in diameter and shape (round or square in cross-section). The choice of the precise placement for the bracket and the selection of wire diameter and shape make it possible to control the dislocation of each tooth and adjust its inclination and rotation. Elastics (rubber bands) may also be attached to the brackets to help position the teeth.

The appliance is adjusted with repositioning of brackets and archwires as the teeth move and new applied forces are necessary to conduct the teeth to the desired position. Several aspects of malocclusion may be dealt with at overlapping time frames. In general, the teeth are leveled and aligned to form a smooth curve of Spee, then class II and III malocclusions are corrected, the upper and lower arches are coordinated to achieve proper overbite and overjet, space is created and used to align the teeth and the final position, inclination and rotation of each tooth is fine-tuned. The treatment may also involve the use of other appliances, such as a headgear to promote anteroposterior jaw or tooth adjustments or a transpalatal bar or lingual arch to adjust the width of the arch and/or produce space anteriorly. Variations of braces include ceramic braces in which the tooth-colored brackets are less visually disruptive, lingual braces in which the brackets and arch wire are attached to the lingual surfaces of the teeth to conceal the entire appliance, and gold-plated or titanium braces for patients allergic to the nickel in the stainless steel.

Clear aligners

Clear aligners have been conceived in the middle of the 20^th century and became popular at the turn of the millennium. They are a less aesthetically disruptive alternative to braces. Treatment with clear aligners was initially only applicable when the necessary changes were small and restricted to the front teeth, but the development of the technique has greatly expanded its applicability to posterior teeth and to complex and profound corrections of tooth positioning. Its effect on skeletal elements is reduced, however, especially when lateral adjustments are needed. Hyrax or Herbst appliances are commonly included in the treatment to promote such adjustments.

A precise digital 3D model of the mouth of the patient is built and software is used to calculate the movements needed in each tooth for the dentition to reach the targeted alignment. The model is usually built after digitization of a cast of the patient's dentition. Intraoral scanners (wands with light and camera) are becoming available, however, for direct digitization at the clinic, eliminating the need for a cast.

Software is used to estimate the forces needed to be applied to each tooth. It then balances the forces and designs a series of aligners that will gradually reposition all teeth. Each clear aligner covers multiple teeth and has a fixed shape although it is slightly flexible. Small patches of composite material called “attachments” may be added at specific positions on some teeth to improve the anchorage of the aligner and facilitate specific tooth movements. The patient wears each aligner for a certain amount of time and switches to the next one, reaching aligned teeth at the end of the series. The treatment may be interrupted near the middle for a reevaluation with new aligners being produced based on a new scan of the mouth. This accounts for eruption or loss of teeth, modification of their shape due to restorative treatment (cavities), noncompliance of the patient or changes in plans. A second interruption (called refinement) with scanning and production of new aligners may take place near the end of the treatment. The goal is to correct for teeth that did not respond exactly as predicted to the applied forces. This final adjustment usually results in a fine-tuned alignment that closely matches the targeted one.

Retainers

Relapse is a tendency of teeth to return to their original position after being dislocated through orthodontic treatment. It is a concern both when braces or clear aligner are used in the orthodontic treatment. Tooth relapse may occur due to recoil of periodontal fibers, pressure from surrounding soft tissues, occlusal forces, and the patient’s continued growth and development. Orthodontic retainers are custom-made devices, usually made of wires or clear plastic, that hold teeth in position after they reach their targeted positions. By using retainers to hold the teeth in their new position for some time, the surrounding tissues are allowed to stabilize in the new condition and reduce the risk of relapse. The advisable duration of retainer usage depends on many factors involving the extent and type of orthodontic procedure, and the physiology and behavior of the patient. Some patients are advised to wear retainers for life.

The most common retainers (Hawley type) are movable. They should be worn at night and the need to wear them during the day has not been established. They consist of wires that surround the anterior teeth and insert into an acrylic base. They are custom-molded for each patient. Other types of retainers include vacuum-formed removable retainers, which are made or plastic and can be transparent like clear aligners, and fixed retainers.

Orthodontic treatment in animals

Malocclusions are common in pets. These animals do not encounter in captivity the variety of food items that they would find in the wild. Their diet may be inappropriate or too limited, leading to gastrointestinal diseases, cavities and abscesses that develop into malocclusions. Animals with constantly growing teeth (ex: rodents, lagomorphs) are frequently fed insufficiently abrasive diets. They experience excessive growth of incisors and molars which inevitably lead to acquired malocclusion. Treatment frequently includes trimming with a diamond-impregnated cutting disc and dietary advising of the pet owner.

Animals such as dogs and cats naturally have canines that greatly exceed the length of the other teeth. In a normal bite, the mandibular canine remains anterior to the maxillary canine. Both teeth have a buccal inclination that prevents them from piercing the opposing arch. Developmental misalignment of the canines can lead to severe and painful damage to the palate, the gums or to neighboring teeth. Such conditions can be treated with extractions, bone surgery or with fixed appliances resembling “customized braces”. Fixed appliances can be highly effective but their use is complicated by the great variation in facial size and morphology present in the group and by the patient's attempts to remove the appliance.

Horses can present any of the basic three classes of malocclusions recognized in humans. Class II malocclusions are common and can result in overjets of 2-3 cm between mandibular and maxillary incisors. They are usually treated with a bite plane or with wiring techniques (braces). A bite plane is a rigid pad (usually acrylic) that is attached to the maxillary incisors, providing and anteriorly-inclined plane for the mandibular incisors to occlude against. Biting then produces anterior traction on the mandible which helps it to grow longer, in juveniles, reducing the malocclusion. Class III malocclusions are commonly seen in miniaturized breeds. Chewing in horses involves substantial lateral excursion of the mandible but also some antero-posterior movement. This later movement is impaired by abnormally long teeth during chewing. The treatment of a malocclusion can also include shortening of an overlong tooth to unlock the movements of the mandible for normal chewing.

Problems with teeth and jaw alignment are identified using

• a visual examination and photographs
• x-rays of the teeth and jaws
• impressions or scans of the teeth.

Some common orthodontic problems are:

• excessive overbite – when the top teeth bite over the bottom teeth more than usual. With teeth closed, you would usually expect to see about half of the lower teeth. If you see less than half, this could be an excessive overbite
• underbite – when the bottom jaw sits further forward than normal. When teeth are closed, the lower front teeth sit in front of the upper front teeth
• protruded teeth – when the upper jaw sits further forward than the lower jaw. With the teeth together, you would expect the upper teeth to sit on the inside of the lower lip. If they sit over the lower lip, this might be a sign of protruded teeth. A person with protruded teeth is more at risk of tooth damage or loss from accidents and may have speech or eating problems. Many people also choose to correct protruded teeth for cosmetic reasons
• crowded teeth – when there is not enough space for teeth to be straight and they overlap, grow crooked, or cant come out fully. This Can be caused by large teeth, a small jaw, or both.
• spacing and gaps – when there is too much space available. This can be caused by small teeth, misshaped teeth, missing teeth, teeth that don’t come out fully, a large jaw or a combination of causes.

A range of orthodontic devices may be used to move teeth, or to keep them in place. These include:

• fixed braces – tiny brackets are attached to the front or back of each tooth, and a wire is tied to them. The constant gentle pressure of the wire slowly moves the teeth
• clear aligners – also known as ‘invisible braces’, clear aligners are a series of clear pieces of custom-moulded plastic that sit over the teeth and slowly move them. While you usually need to wear clear aligners for 20–22 hours a day, you are able to take them out to eat, drink and clean them
• elastics – these small rubber bands are stretched between upper and lower braces for extra force to move teeth
• plate – a plastic device that sits in the mouth and uses wires and springs to move teeth, or to hold them in place. Unlike fixed braces, a plate can be taken out of the mouth.
• surgery – in severe cases, surgery may be required to remove buried teeth, or make it easier for them to come out. Surgery can also be useful when there is a problem with the jaws, or to improve the outcome of orthodontic treatment.

Age for orthodontic treatment

Problems that may benefit from orthodontic treatment can be detected at an early age by an oral health professional . Most orthodontic treatment is done after all the permanent teeth have come through,. Some treatment can be started earlier,which can help avoid major treatment later on. . Adults of any age can have treatment as well if they have orthodontic problems.

Risks of orthodontic treatment

Some of the risks of orthodontic treatment include:

• dental hygiene problems – this makes cleaning the teeth more difficult and increases the chance of gum disease, tooth decay, stains and discolourations. It is important that teeth are cleaned thoroughly after every meal, at least twice a day, and to reduce snacking and unhealthy food and drinks during orthodontic treatment to avoid these problems
• soft tissue injury – braces may dig into the gums or cheeks, injuring them
• relapse – the corrected teeth can move again once braces are taken off. retainers are worn after braces have been taken off is to prevent this from happening.

Orthodontic treatment is provided by an orthodontist, and some dentists. An orthodontist is a dentist who has done additional study to specialise in the diagnosis, prevention and treatment of problems in the alignment of teeth and jaws.

The orthodontist or dentist will take detailed records of your teeth and jaw, diagnose any problem, plan the treatment and carry out the care as required.

Costs vary depending on the type of problem and the amount of treatment needed. Ask your oral health professional for advice.

Talk to your orthodontist or oral health professional about how to care for your teeth during treatment.

For example, if you’ve got braces, it’s even more important to brush, floss, and clean between your teeth regularly, as the brackets and wires can retain or trap more food particles and plaque. If using string or tape is too tricky, there are other methods to help keep the teeth and gums clean, such as floss threaders for braces or interdental toothbrushes.

Interdental toothbrushes are small brushes that have been designed to get into small spaces including around brackets and the gaps between teeth. They can be particularly helpful when undergoing braces treatment.

Your dentist tells you that you need braces, bringing back not-so-fond memories of kids being called “Metal Mouth.”

Take heart. Braces have evolved over the years and new alternatives in both look and materials are available. FDA is responsible for reviewing these devices for safety and effectiveness and, as appropriate, granting marketing authorization for the devices before they can be sold.

Here are answers to some of the most common questions about braces, provided by dental experts at FDA.

Some Common Questions

Q: I thought braces were just for kids. Not so?

A: Not anymore. According to the American Association of Orthodontics, these days, one out of five orthodontic patients is over the age of 21. (Orthodontics is a branch of dentistry dealing with irregularities in the teeth by straightening them.) So while you may have foregone wearing braces as a kid, you’re never really too old to do something about straightening your teeth.

Q: Why do I need to wear braces?

A: Simply put, braces will straighten your teeth. Not only will you look better, but it will also help you maintain good dental hygiene. Crooked or crowded teeth can be hard to clean, causing inflamed and infected gums and other forms of dental disease. Wearing braces now can go a long way toward helping you maintain healthy teeth and gums down the road.

Q: Do I have to have a mouth full of metal?

A: Your dentist or orthodontist will need to make that determination based on your dental exam. If metal braces will do the job the best, know that many metal braces today are smaller than they used to be, less obtrusive, and can be clear or colored to match the color of your teeth. And if you’re feeling expressive, the rubber bands that connect to the brackets in place now come in different colors.

In addition, you may know there are now clear braces (called aligners), such as Invisalign, that are nearly invisible. These tend to cost a little more than metal ones do and they don’t work for everyone’s teeth, but you can ask the orthodontist if they are an alternative for you.

Q: How do metal braces work?

A: Braces move teeth by applying pressure. The braces usually consist of small brackets cemented to your teeth, connected by a wire and held to the brackets by rubber bands. The wire is regularly tightened by the dentist or orthodontist to gradually shift your teeth and jaw. The brackets may be metal or tooth colored.

Q: How do “invisible” braces work?

A: Invisible braces, called aligners, are made of clear plastic material and are worn over your teeth to straighten them. You’ll wear each custom-made aligner for a few weeks or maybe a month. Then you get a new set for the next stage of your treatment. This way, your teeth are gradually moved into the correct position according to your personal treatment plan.

Aligners are removable and need to be taken out before you eat, brush, and floss, making maintaining good dental hygiene much easier than with metal braces. Because they are removable, you must be sure to follow your dentist or orthodontist’s instructions on how long to wear them each day (typically, about 22 hours).

Q: How long will I have to wear braces?

A: That depends on how problematic the dentist or orthodontist thinks your teeth are. An average time period is two years; it may be take a little more time or a little less.

There really is no “faster” method of straightening teeth. Orthodontics work by applying slow pressure that affects the bone surrounding a tooth to allow it to move. If movement is too rapid, tooth loss or a breakdown of the bone can occur.

Q: Isn’t it hard to clean teeth when you have metal braces?

A: Yes. It’s easy for food to get stuck in metal braces, so you have to be extra careful to keep your teeth clean and free of food material. Not cleaning your teeth really carefully can cause cavities, limit the effectiveness of your braces, and prolong the amount of time you’ll have to wear them. You may want to check in at the dentist’s office every 3 or 4 months rather than the usual twice a year to ensure that your teeth are well cleaned.

Q: Now my orthodontist says I need to wear a retainer. What’s that for?

A: Retainers, worn nightly after you’re done with the braces, help maintain tooth position so that the bone in the tooth can solidify in the new position.

Q: Are there certain types of food I should avoid eating when I have braces?

A: Yes. You should avoid eating anything chewy or sticky, like gummi bears, and chewing gum, and should try not to eat hard candies, as these can damage the braces, prolonging the time you have to wear them.

Technique combining controlled eruptive TOOTH MOVEMENT TECHNIQUES and incision of the supracrestal gingival attachment to allow for proper restoration of a destroyed or damaged crown of a tooth. Controlled eruption of the tooth is obtained using ORTHODONTIC APPLIANCES. During this eruptive phase, repeated incisions are made at the junctional epithelium of the sulcus and the supracrestal connective tissue to prevent coronal displacement of the gingiva and of the attachment apparatus.

Selective grinding of occlusal surfaces of the teeth in an effort to eliminate premature contacts and occlusal interferences; to establish optimal masticatory effectiveness, stable occlusal relationships, direction of main occlusal forces, and efficient multidirectional patterns, to improve functional relations and to induce physiologic stimulation of the masticatory system; to eliminate occlusal trauma; to eliminate abnormal muscle tension; to aid in the stabilization of orthodontic results; to treat periodontal and temporomandibular joint problems; and in restorative procedures. (From Jablonski, Dictionary of Dentistry, 1992)

Orthodontic movement in the coronal direction achieved by outward tension on the PERIODONTAL LIGAMENT. It does not include the operative procedure that CROWN LENGTHENING involves.

Orthodontic appliances, fixed or removable, used to maintain teeth in corrected positions during the period of functional adaptation following corrective treatment. These appliances are also used to maintain the positions of the teeth and jaws gained by orthodontic procedures. (From Zwemer, Boucher's Clinical Dental Terminology, 4th ed, p263)

Therapeutic closure of spaces caused by the extraction of teeth, the congenital absence of teeth, or the excessive space between teeth.

Wires of various dimensions and grades made of stainless steel or precious metal. They are used in orthodontic treatment.

An orthodontic method used for correcting narrow or collapsed maxillary arches and functional cross-bite. (From Jablonski's Dictionary of Dentistry)

Orthodontic techniques used to correct the malposition of a tooth or teeth.