What causes a tooth to rotate or tip when force is applied?

When force is applied to a tooth, the point of application affects how the tooth will move. The correct answer highlights that when force is applied anywhere other than the center of resistance, the tooth will experience a tipping or rotational effect.

The center of resistance is a crucial concept in orthodontics; it is the point around which a tooth will move without tipping. If a force is applied at any other point, such as the crown or incisal edge, it creates a moment or leverage that causes the tooth to rotate around the center of resistance. This results in either tipping (when a tooth's crown moves in one direction while the root moves in another) or complete rotation.

For instance, if you push the incisal edge, the crown of the tooth will move in the direction of the force, while the root will lag behind due to the resistance provided by the periodontal fibers. This results in a tipping motion rather than a translation (where the tooth would move straight without tipping). Understanding the mechanics of force application helps in planning tooth movement effectively during orthodontic treatment.