How does an orthodontic spring work?

Low grade pressure: All active orthodontic appliances work by applying low grade pressure by either push or pull over a period of time. Cells in the bone are activated to decalcify and the bone actually gets soft allowing the tooth to move. Almost all movement of the targeted tooth is accompanied by looseness and some discomfort that stops when the tooth gets where it is intended to go.

Sustained Pressure: An orthodontic spring works by applying a consistant and continuous force to a tooth or group of teeth. Because of this continual pressure, it slowly moves a tooth (or teeth) in the direction that the spring is expanding. The idea is similar to elastic bands or wires, which also move teeth. Depending on the type and direction of movement, a spring may be better suited than those other options.

Many types: There are so many types of springs and spring forces used in orthodontics, it is difficult to ascertain what one you are asking about. There are springs designed to pull and those to push and they can be used in any number of ways. The intent is typically to move teeth in a desired direction.

Forces: An active spring that is compressed between teeth tries to expand, putting forces on both teeth on each side of the spring (pushing them apart). A passive spring placed between teeth exerts no force but prevents the teeth from moving together (towards each other).

Open or close spaces: There are two types of springs, open coiled springs and closed coiled springs. Open coiled springs are compressed between two teeth to open space. If a tooth is blocked out between two teeth, an open coilded spring can be used to open sufficient space to bring the blocked out tooth into alignment. A closed coiled spring can be used to close spaces between teeth or move a tooth unilaterally.

Force: Springs are used to push or pull teeth in specific directions. As spring is compressed or stretched, energy is stored in the spring. Over time that energy is expressed, producing the desired tooth movement.