Chi-Ching Chang (1) (2) (3), Sung K. Kim (4), Chun-Teh Lee (1)
Journal of Dentistry. Volume 120 (May 2022). DOI: https://doi.org/10.1016/j.jdent.2022.104083

Keywords

CBCT imaging, immediate implants, alveolar bone remodeling, digital dentistry

Abstract

Objectives: Studies have evaluated changes in hard tissue following immediate implant placement (IIP) through cone beam computed tomography (CBCT) imaging. This study compared the 3D volumetric changes of the alveolar bone at immediate implant sites with 2D linear measurement outcomes by using a novel image analysis workflow. Methods: Preoperative and 6-month postoperative CBCT images of patients who underwent IIP and bone grafting in the maxillary esthetic area were acquired. Linear and volumetric measurements of buccal bone dimensions were taken using a specially designed workflow. The 2D and 3D measurements were compared, and their correlations were determined. Results: Images from 13 patients (13 implants) were analyzed. Linear measurements revealed that the general linear buccal bone loss was less than 1mm in all segments. The 3D volumetric bone reduction (reported as median [first quantile, third quantile]) in the vertical, cervical, middle, and apical segments was 14.27 [11.33, 30.66] mm3 (51.30 [42.78, 66.91]%), 16.20 [10.35, 30.52] mm3 (18.20 [9.88, 24.74]%), 17.48 [8.42, 21.17] mm3(24.05 [12.39, 28.22]%), and 6.87 [3.88, 9.45] mm3 (11.34 [5.14, 22.54]%), respectively. Significant positive correlations between 2D and 3D measurements were consistently identified in the cervical and middle segments, but no significant correlation was noted in the vertical segment. Conclusions: The results revealed that linear measurements could not fully represent volumetric bone dimensional changes. Performing volumetric measurements and 3D rendering could be valuable in presenting the actual amount and topography of peri-implant bone remodeling. Clinical Significance: Linear measurements only partially represent the real-life event of 3D bone changes at immediate implant sites. Factors affecting hard tissue alterations following IIP should be reassessed using 3D volumetric measurement outcomes.

How Our Software Was Used

Image processing and quantification analyses were conducted using Dragonfly. Image processing included thresholding gray values using Otsu's algorithm, registration of preoperative and postoperative images, and creating regions of interest representing baseline bone and bone loss. Analysis included demonstrating the location and amount of bone loss by thickness meshes, and measuring changes in bone dimension in two-dimensional (2D) coronal views.

Author Affiliation

(1) Department of Periodontics and Dental Hygiene, The University of Texas Health Science Center at Houston School of Dentistry, 7500 Cambridge Street, Suite 6470, Houston, TX 77054, USA
(2) Department of Periodontics, Chang Gung Memorial Hospital, No.199, Dun-Hua North Rd., Taipei 105406, Taiwan
(3) Chang Gung University, No.259, Wenhua 1st Rd., Taoyuan City 333323, Taiwan
(4) Department of Diagnostic and Biomedical Sciences, The University of Texas Health Science Center at Houston School of Dentistry, 7500 Cambridge St., Houston, TX 77054, USA