Abstract

Root Position Control with TADs Based on Cone Beam CT

by Lee Jang Yeol

The aim of orthodontic treatment is to establish a harmonious occlusion of the maxillary and mandibular teeth along with the proper jaw relationship. If the sagittal position of the maxilla and mandible is severely displaced, orthognathic surgery is necessary, but if the amount of skeletal discrepancy is not large, good occlusion and facial esthetics can be achieved through orthodontic camouflage treatment. Especially, it is fortunate that this kind of camouflage treatment has been more possible and successful since we used skeletal anchorage in orthodontic field. However, it is important to form a good occlusion at the crown level, but more in-depth consideration is required on how to set the position of the root, which is an important aspect in securing long-term stability from a physiological, periodontal, and biomechanical viewpoint. Dental cone beam CT is capable of three-dimensionally evaluating the spatial relationship between the apical root and the surrounding cortical bones. This is more accurate and visual than evaluation through the past panoramic X-rays or 2D lateral cephalometric radiograph. In addition, it is possible to predict and recognize the risk factors of root resorption or alveolar bone damage in advance through the evaluation of cortical bone proximity to apical roots, and it is possible to visually confirm the results of the bone remodeling process of the surrounding alveolar bone before and after treatment. Therefore, in this presentation, I will look at the considerations necessary for planning the location of the roots during orthodontic camouflage treatment according to each skeletal malocclusion and consider the problems that may arise when these parts are overlooked. In addition, I would like to discuss treatment strategies and biomechanical considerations to solve problems, look at changes in root position that can occur after long-term observation, and review how to control factors that affect long-term treatment stability. In addition, through this process, I will discuss the method of setting a more analytical and detailed goal-oriented treatment planning for the target position of the anterior crown and root from the initial treatment planning stage.

Learning Objectives

After this lecture, you will be able to understand the method of evaluation of root proximity to surrounding cortical bones in sagittal and axial way from dental cone beam CT.
After this lecture, you will be able to understand the considerations necessary for planning the location of the roots during orthodontic treatment.
After this lecture, you will be able to understand long-term changes in root position and controlling factors that affect long-term stability.