What is the result if no force is applied at the center of resistance during orthodontic movement?

In orthodontic mechanics, the center of resistance plays a critical role in determining how a force applied to a tooth influences its movement. If no force is applied at the center of resistance, the result is typically unwanted tipping of the tooth.

When a force is applied to a tooth, it acts through its center of resistance. If the force does not pass through this point, the tooth will experience not only translation (movement in a straight line) but also rotation about its center of resistance. This rotational movement leads to tipping, where the crown of the tooth moves in one direction while the apex moves in the opposite direction, rather than achieving the desired straight-line movement.

This phenomenon underscores the importance of understanding the locations and effects of forces in orthodontic treatment. Therefore, the presence of a force not aligned with the center of resistance leads to unintended tipping, complicating treatment outcomes and prolonging the process.