torque values built in so that each rectangluar archwire can be contorted to form a custom fit without inadvertently shifting any correctly positioned teeth. Without bracket angulation and torque, second-order or tip bends would still be required on each patient's archwire. Methods A typical treatment for incorrectly positioned teeth (malocclusion) takes from one to two years, with braces being adjusted every four to 10 weeks by specialists called orthodontists, university-trained dental specialists versed in the prevention, diagnosis and treatment of dental and facial irregularities. Orthodontists offer a wide range of treatment options to straighten crooked teeth, fix irregular bites, and align the jaws correctly. There are many ways to adjust malocclusion. In growing patients there are more options to treat skeletal discrepancies, either by promoting or restricting growth using functional appliances, orthodontic headgear or a reverse pull facemask. Most orthodontic work begins in the early permanent dentition stage before skeletal growth is completed. If skeletal growth has completed, jaw surgery is an option. Sometimes teeth are extracted to aid the orthodontic treatment (teeth are extracted in about half of all the cases, most commonly the premolars). Orthodontic therapy may include using fixed or removable appliances. Most orthodontic therapy is delivered using appliances that are fixed in place, for example, with braces that are adhesively bonded to the teeth. Fixed appliances may provide greater mechanical control of the teeth; optimal treatment outcome is improved by using fixed appliances. Fixed appliances may be used, for example, to rotate teeth if that do not fit the arch shape of the other teeth in the mouth, to adjust multiple teeth to different places, to change tooth angle of teeth, or to change the position of a tooth's root. This treatment course is not preferred where a patient has poor oral hygiene, (as decalcification, tooth decay or other complications may result. If a patient is unmotivated (insofar as treatment takes several months and requires commitment to oral hygiene), or if malocclusions are mild. Biology of tooth movement and how advances in gene therapy and molecular biology technology may shape the future of orthodontic treatment. Braces Braces are usually placed on the front side of the teeth, but they may also be placed on the side facing the tongue (called lingual braces). Brackets made out of stainless steel or porcelain are bonded to the center of the teeth using an adhesive. Wires are placed in a