When the center of rotation is at the incisal edge, what type of movement is attained?

When the center of rotation is positioned at the incisal edge, the type of movement achieved is known as reverse tipping. In this scenario, as the force is applied to the crown of the tooth, the root moves in the opposite direction compared to the crown. This results in the crown being displaced away from the center of rotation (the incisal edge), while the root moves mesially. This action is typically observed when the crown is pushed in a direction, and the root follows more slowly due to its anchorage in the bone.

Reverse tipping is particularly significant in orthodontics because it can lead to a more favorable movement of the tooth into the desired position without excessive root resorption or damage to the periodontal tissues, as the apex of the root tends to remain stable while the crown moves in the desired corrective direction. This understanding is crucial when planning orthodontic interventions to ensure effective and safe tooth movements.