Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 05 Mar 2025

Effects of printing layer thickness and build orientation on the mechanical properties and color stability of 3D-printed clear aligners

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DOI: 10.2319/081624-672.1
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ABSTRACT

Objectives

To determine effects of printing layer thickness and build orientation on mechanical properties and color stability of direct 3D-printed clear aligner resin.

Materials and Methods

Specimens were printed using 3D printed clear aligner resin with two printing layer thicknesses (50 µm, 100 µm) and three build orientations (90°, 60°, and 45°). Mechanical properties (tensile stress, tensile strain, and elastic modulus), color stability in coffee and artificial saliva, and roughness were then evaluated.

Results

Specimens printed with a 50 µm layer thickness and orientation at 90° demonstrated superior color stability in artificial saliva. However, all specimens showed high susceptibility to coffee staining regardless of layer thickness or orientation. Mechanical properties were improved in the order of 90° < 60° < 45° build orientation, showing statistically significant differences (P < .05). Surface roughness was increased in the order of 90° < 60° < 45° build orientation, showing statistically significant differences (P < .05).

Conclusions

Printing layer thickness and orientation exerted significant effects on mechanical properties, color stability, and surface roughness of 3D-printed clear aligner resin.

Keywords: 3D printing clear aligner resin; Layer thickness; Build orientation; Color stability; Surface roughness
Copyright: © 2025 by The EH Angle Education and Research Foundation, Inc.

Contributor Notes

aGraduate Student, Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Republic of Korea.
bAssistant Research Professor, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, Republic of Korea.
cAssociate Professor, Department of Prosthodontics, The Affiliated Hospital of Qingdao University, Qingdao University, School of Stomatology of Qingdao University, Qingdao, Shandong, China.
dStaff Scientist, Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
eProfessor, Department of Preventive and Restorative Sciences, School of Dental Medicine, Center for Innovation & Precision Dentistry, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, USA.
fProfessor, Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Republic of Korea.
gAssistant Professor, Department and Research Institute of Dental Biomaterials and Bioengineering, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, Republic of Korea.
hAssociate Professor, Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Republic of Korea.
Corresponding author: Sung-Hwan Choi, DDS, MSD, PhD, Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea (e-mail: selfexam@yuhs.ac)
Received: 16 Aug 2024
Accepted: 30 Dec 2025
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