Final answer:
Wolff's law is demonstrated when braces apply stress to the teeth and cause remodeling of the jaw bones to accommodate and support the new positions of the teeth. The law explains how bones adapt to the stresses placed on them, thereby strengthening in areas of high stress. Orthodontic treatment is carefully planned to leverage Wolff's law without exceeding the limited elastic region of bone before fracture as per Hooke's law.
Step-by-step explanation:
When braces apply stress to the teeth, causing remodeling of the jaw bones, this is an example of Wolff's law in action. Wolff's law describes the adaption of bones in response to the stresses placed upon them, leading to changes in the bone's structure to better accommodate those stresses. This biological principle dictates that bone density increases in areas subjected to stress, while it decreases in areas that are not stressed. It implies that the mechanical forces acting on bones can remodel the bone structure, thereby strengthening it in response to consistent stress.
In the case of orthodontic braces, the wires exert force on the teeth. This force, Fapp, points toward the back of the mouth and applies tension to the teeth that need to be realigned. Over time, the bone remodels itself to accommodate the new positions of the teeth, facilitated by the principle of Wolff's law. The jaw bones gradually adapt to the sustained pressure by allowing teeth to move, and ultimately leads to an altered and usually improved bone architecture, aligning the teeth into their desired positions.
Unlike metals or springs, which have a larger region in which Hooke's law applies, bones are not as flexible and have a smaller elastic region before fracture occurs. Hooke's law states that deformation is proportional to the applied force, which can be visualized with the extension AL of a spring or human bone. However, due to the brittleness of bones, they have a small elastic region, and applying a force beyond this limit can lead to breaking or fracturing rather than simply deforming elastically.