In uncontrolled tipping, where is the center of rotation located?

In the context of uncontrolled tipping, the center of rotation refers to the point around which a tooth rotates when subjected to orthodontic forces. Specifically, this concept is essential in understanding how teeth move when force is applied.

The correct placement of the center of rotation in uncontrolled tipping is at the middle of the tooth. This is because, during uncontrolled tipping movements, the tooth tilts around its long axis due to the force being applied. When the center of rotation is at the middle, the tooth experiences a combination of tilting and translation, primarily around that central point.

For example, if the force is applied above the center of rotation, the tooth will tip away from that force, creating a downward movement at one end (the apex) and an upward movement at the other end (the occlusal surface). This movement highlights how it is not confined solely to a rotational movement around the apex or occlusal surface but rather occurs in a manner that involves the central positioning in the middle of the tooth.

In contrast, other locations like the apex, gum line, or occlusal surface would imply different types of movements or mechanics, such as pure tipping or intrusion/extrusion, rather than uncontrolled tipping around a central point. Thus,