How Braces Move Teeth
During consultations, I am frequently asked, “How do braces move teeth?” While the look, size and force of orthodontic appliances has changed significantly compared to those used in treatment several decades ago, the means by which the teeth move remains essentially the same.
Small brackets are bonded to the teeth. Brackets are made to conform to the size and shape of a particular tooth and contain a prescription that will result in each tooth being placed at an ideal position for that type of tooth. A wire is then inserted into the slot in the center of the brackets. The wire is held in place by elastic ties placed around the wire and brackets. These days the ties can either match the metal or tooth-colored brackets, or come in a wide array of colors for those who prefer to decorate their appliances. Initially, while the teeth are the most misaligned, the wires are extremely flexible and are of small diameter, applying gentle pressure to the teeth. As the teeth gradually straighten, progressively larger diameter wires are placed, and they are less flexible. However, because the teeth are straighter as these larger wires are placed, the amount of pressure remains gentle. As treatment progresses, some patients will require the use of rubber bands, which are attached by patients to their braces. These do not straighten the teeth, but correct the way the teeth meet one another (the bite).
As gentle pressure is placed on the teeth, the bone and ligaments supporting the teeth respond by changing their shape. This change allows the teeth to move to the corrected positions and also loosens the teeth slightly. At the time treatment is completed and the braces are removed, the teeth are still slightly mobile, which is why retainers are given. Retainers are critical in allowing the changes obtained to be stabilized. As time goes by, the time required for retainer wear is reduced as the bone and ligaments accommodate to the changes brought about by the braces.
Today’s braces are more esthetic, smaller and more comfortable than the braces of yesteryear, but the processes occurring around the teeth to allow them to move have not changed since the human mouth has remained the same!