What is the movement of the center of resistance with root resorption in a single-rooted tooth?

The center of resistance in a single-rooted tooth typically moves up when root resorption occurs. This phenomenon can be attributed to the loss of the root structure, which affects the anchorage of the tooth in the bone. As root resorption progresses, the remaining root length decreases, consequently altering the position of the center of resistance.

The center of resistance is generally located in the area of the root that provides the most stability during force application. With root resorption leading to a reduced root size, the center of resistance shifts upward relative to the original tooth anatomy. This shift is significant for orthodontic treatment because it influences the biomechanics of tooth movement; orthodontists must take into account the new position of the center of resistance when planning movement strategies.

This upward movement contrasts with the other possibilities where one might assume the center remains static or disappears, which does not align with the physiological changes that occur during resorption. The understanding of how the center of resistance is affected by root resorption is crucial for effectively designing and implementing orthodontic force systems.