https://ir.ymlib.yonsei.ac.kr/handle/22282913/169037 2026-04-30T02:46:25Z 2026-04-30T02:46:25Z Hong, Hyeon Gi Nguyen, Hieu Alkhamees, Amani Lee, Kee-Joon https://ir.ymlib.yonsei.ac.kr/handle/22282913/210269 2026-02-05T00:26:14Z 2026-06-01T00:00:00Z

Title: Non-surgical treatment of adult skeletal class III patient with severe alveolar bone loss by sequential segmental displacement and third molar extraction: A case report Authors: Hong, Hyeon Gi; Nguyen, Hieu; Alkhamees, Amani; Lee, Kee-Joon Abstract: Compromised periodontal conditions pose challenges in orthodontic treatment. In particular, maxillomandibular skeletal discrepancies may require large-scale tooth movement, making it essential to avoid round-tripping movements to minimize dental and periodontal side effects. This case report describes a 49-year-old male patient with skeletal Class III malocclusion and severe alveolar bone loss, particularly affecting the anterior teeth, who sought non-surgical treatment with aesthetic lingual orthodontic appliances. A comprehensive diagnosis and treatment plan were formulated to establish a flat occlusal plane and Class I molar relationship while minimizing round-tripping of the anterior segment. Segmental distalization of mandibular molars, followed by intrusion of the mandibular incisors, was performed with the aid of miniscrews to achieve normal occlusion and an improved facial profile without further alveolar bone loss. This case report highlights the use of segmental archwires and an orthodontic force system based on the centre of resistance to preserve periodontal support in a middle-aged patient with skeletal Class III malocclusion and severe alveolar bone loss.

2026-06-01T00:00:00Z Mangal, Utkarsh Jinn, Hyeonseok Hyun, Chang Min Kim, Harim Cha, Jung Yul Lee, Kee-Joon Choi, Sung-Hwan 만갈 웃커시 https://ir.ymlib.yonsei.ac.kr/handle/22282913/211531 2026-03-26T05:07:06Z 2026-05-01T00:00:00Z

Title: Facial surface tracing approach to reduce the observation errors in 3D curvilinear landmark annotations on cone-beam computed tomography images Authors: Mangal, Utkarsh; Jinn, Hyeonseok; Hyun, Chang Min; Kim, Harim; Cha, Jung Yul; Lee, Kee-Joon; Choi, Sung-Hwan; 만갈 웃커시 Abstract: Objectives: To propose and validate a 3D facial surface tracing (3D-FAST) algorithm as a robust tracing method to reduce observation errors in identifying maxillofacial curvilinear landmarks. Methods: The 3D-FAST algorithm comprises four sequential steps: (1) extraction of bone structures from cone-beam computed tomography (CBCT) volumes utilizing Otsu's thresholding method; (2) conversion of segmented volumetric data into a mesh representation through the marching-cubes algorithm; (3) initial landmark identification employing a data-driven approach, followed by selective manual refinement; and (4) optimization of landmark positions by identifying maximal or minimal points within defined curvilinear regions. The algorithm's efficiency was validated using 55 CBCT datasets, with particular emphasis on the Orbitale landmark. Annotation efficiency was assessed by comparing landmark deviations, dihedral angles between reference planes, and asymmetry measurements with independent manually annotated datasets. Results: Compared to orthodontically trained CBCT users, 3D-FAST demonstrated the highest consistency with the centroid derived from user annotations. In constructing horizontal and vertical reference planes and conducting asymmetry analyses, reference planes generated by 3D-FAST showed significantly improved dihedral angle variation and asymmetry than those generated by an experienced CBCT human observer, the most consistent and experienced manual user. In addition, 3D-FAST achieved improved consistency when bilateral Orbitale landmarks were used for reference plane construction, compared to when unilateral Orbitale landmarks were used. Conclusions: 3D-FAST is a reliable method for annotating curvilinear landmarks in CBCT images. Clinical significance: 3D-FAST has the potential to enhance clinical workflows and outcomes by reducing the learning curve, minimizing subjectivity, and saving time.

2026-05-01T00:00:00Z Choi, Eun-Hack Andrew Shin, Yunji Yu, Jae-Hun Kim, Jeenyoung Mangal, Utkarsh Kim, Jun-Young Choi, Sung-Hwan 만갈웃커시 https://ir.ymlib.yonsei.ac.kr/handle/22282913/211534 2026-03-27T02:17:29Z 2026-04-01T00:00:00Z

Title: Clinical acceptability and repeatability of three-dimensional maxillary positioning following orthognathic surgical wafer placement: An in vitro study Authors: Choi, Eun-Hack Andrew; Shin, Yunji; Yu, Jae-Hun; Kim, Jeenyoung; Mangal, Utkarsh; Kim, Jun-Young; Choi, Sung-Hwan; 만갈웃커시 Abstract: Objectives: To quantify the three-dimensional (3D) deviation between planned and achieved maxillary positions after transfer using a surgical wafer under in vitro conditions, and assess clinical acceptability and repeatability for each workflow. Methods: A bracketed typodont mounted on a mannequin was used to define three groups-Conventional (alginate impressions/plaster casts/laboratory scanning), Trios (Trios 3 intraoral scanner (IOS)), and Prime (Primescan IOS)-each with 10 technical replicates. For each replicate, virtual surgical planning was performed, a wafer was designed and 3D-printed, and the maxilla was positioned; 3D deviation was quantified as: (1) point-based 3D positional deviation (three landmarks) and (2) matrix-based 3D translational and rotational deviations. Clinical acceptability was defined as the proportion of the 10 replicates per group with 3D deviation within predefined clinical tolerance limits (0.5 mm for positional/translational; 1.0 degrees for rotational). Repeatability was summarized by the repeatability standard deviation (sr) as specified in ISO 5725. Results: The Trios and Prime groups achieved 100% clinical acceptability across all 3D deviations. In the Conventional group, acceptability was 90% for the anterior landmark's positional and translational deviation, with all others achieving 100%. The sr was 0.13-0.20 mm (positional), 0.23 mm (translational), and 0.22 degrees (rotational) for the Conventional group; 0.04-0.13 mm, 0.06 mm, and 0.24 degrees for the Trios group; 0.04-0.10 mm, 0.11 mm, and 0.17 degrees for the Prime group. Conclusion: Under in vitro conditions, the demonstrated clinical acceptability and repeatability provide preliminary evidence supporting the clinical feasibility of a fully digital IOS-based workflow for wafer-mediated maxillary positioning. Clinical significance: An IOS-based workflow can be considered clinically feasible for wafer-mediated maxillary positioning without compromising accuracy, as evaluated in terms of clinical acceptability and repeatability, while potentially eliminating impression-taking and cast fabrication steps.

2026-04-01T00:00:00Z Andrews, Richard J. Divaris, Kimon White, Raymond P. Chung, Chooryung J. Nelson, John C. Nguyen, Tung https://ir.ymlib.yonsei.ac.kr/handle/22282913/211884 2026-04-14T07:32:12Z 2026-04-01T00:00:00Z

Title: Three-dimensional insights into miniscrew-assisted rapid palatal expansion asymmetry: A novel cone-beam computed tomography-based analysis Authors: Andrews, Richard J.; Divaris, Kimon; White, Raymond P.; Chung, Chooryung J.; Nelson, John C.; Nguyen, Tung Abstract: Introduction: Miniscrew-assisted rapid palatal expansion (MARPE) is a predictable option for nongrowing patients with maxillary transverse deficiency manifesting as posterior crossbite. However, recent evidence suggests a high frequency of asymmetrical expansion as a complication of MARPE. Methods: Retrospective analysis of 9 patients (mean age: 21.7 years; 65% female; average Yonsei Transverse Index: -4.6 mm) included superimposition of pre (T1) and posttreatment (T2) cone-beam computed tomographies using a voxel-based technique on the anterior cranial base. T1 and T2 cone-beam computed tomographies were digitized in a common Cartesian plane, enabling linear and angular measurements using T1 landmarks as the reference to compare T2 landmarks. Geometric analyses included linear Euclidean left vs right and transverse distances, 3-dimensional (3D) angulation, and 3D matrix rotations to quantify asymmetry. Asymmetry thresholds were set at 2 mm or 2 degrees. Stepwise regression was used to determine the association between potential explanatory variables and asymmetry. Results: There was no statistically or clinically significant asymmetry of the ANS-PNS vector. Linear, angular, or zygomaticomaxillary roll of jugale, keyridge, or zygomaticofrontal suture around the ANS-PNS vector was found (P >0.05). Statistically but not clinically significant linear asymmetry of keyridge (0.9 +/- 0.9 mm; P = 0.02) and first molar furcation (0.7 +/- 0.8 mm; P = 0.02) was found. Stepwise regression did not find any potential explanatory variables explaining the keyridge and the first molar furcation linear asymmetry. Conclusions: Under the conditions of this study and 3D analyses, MARPE resulted in statistically significant linear asymmetry of the keyridge and the first molar furcation. Statistical significance does not equate clinical significance or relevance.

2026-04-01T00:00:00Z