CBCT Imaging for Bracket Positioning with Consideration to Root Axes

Cone-beam computed tomography (CBCT) imaging and computer-aided manufacturing were used to produce stereolithographic trays for indirect-direct bonding. The ability to align teeth considering both the crown and the root decreases the chances for post treatment relapse. Three-dimensional (3D) images for separate brackets in a bracket kit were obtained from CBCT scanning in DICOM format and then converted to stereolithography format using Mimics software. Another CBCT image was obtained for the patients’ dentition. The images were saved in DICOM format and then placed into the Mimics image processing software. The images were enhanced, and the teeth were isolated to gain a clear view of their roots. With both images in the Mimics image-processing software, each bracket was placed on its designated tooth and positioned accurately. After the brackets were placed, a 3D image of a U-shaped stent was added to the project. Then, the image of the stent was placed over the teeth and half of the brackets. In the Mimics software, the teeth and brackets were then subtracted from the image of the tray to have a negative replica. The subtracted image of the tray in stereolithography format was printed with a 3D printer to obtain a 3D printed bracket positioning tray with indentations for bracket seating. This allowed brackets to be seated on the tray and bonded using conventional bonding steps.