What occurs when the center of rotation is at the apex?

When the center of rotation is located at the apex of a tooth, it results in controlled tipping. This phenomenon refers to the specific type of movement where the crown of the tooth tilts in the direction of the applied force while the apex remains relatively stationary. In this scenario, the force applied creates a rotational movement around the apex, allowing for precise control over the tooth’s tipping motion.

Controlled tipping is particularly significant in orthodontics as it enables clinicians to achieve desired tooth movements while minimizing adverse effects on the surrounding tissues. By keeping the center of rotation at the apex, practitioners can carefully guide the tooth alignment without excessive movement, ensuring both effectiveness in achieving treatment goals and safety for the dental structures.

Other types of tooth movements, such as uncontrolled tipping or translation, involve different dynamics and patterns of force application that do not maintain the apex as the center of rotation, resulting in less predictable outcomes or more significant changes in position. Hence, controlled tipping is the specific movement associated with the center of rotation being located at the apex of the tooth.