Comparison of dimensional accuracy between direct-printed and thermoformed aligners

Abstract

Objective:The purpose of this study was to evaluate and compare the dimensional accuracy between thermoformed and direct-printed aligners. Methods: Three types of aligners were manufactured from the same reference standard tessellation language (STL) file: thermoformed aligners were manufactured using Zendura FLX TM (n = 12) and Essix ACE TM (n = 12), and direct-printed aligners were printed using Tera Harz TM TC-85DAP 3D Printer UV Resin (n = 12). The teeth were not manipulated with any tooth-moving software in this study. The samples were sprayed with an opaque scanning spray, scanned, imported to Geomagic ® Control X TM metrology software, and superimposed on the reference STL file by using the best-fit alignment algorithm. Distances between the aligner meshes and the reference STL file were measured at nine anatomical landmarks. Results: Mean absolute discrepancies in the Zendura FLX TM aligners ranged from 0.076 ± 0.057 mm to 0.260 ± 0.089 mm and those in the Essix ACE TM aligners ranged from 0.188 ± 0.271 mm to 0.457 ± 0.350 mm, while in the direct-printed aligners, they ranged from 0.079 ± 0.054 mm to 0.224 ± 0.041 mm. Root mean square values, representing the overall trueness, ranged from 0.209 ± 0.094 mm for Essix ACE TM , 0.188 ± 0.074 mm for Zendura FLX TM , and 0.140 ± 0.020 mm for the direct-printed aligners. Conclusions: This study showed greater trueness and precision of direct-printed aligners than thermoformed aligners.

Accuracy of 3D Tooth Movements in the Fabrication of Manual Setup Models for Aligner Therapy

“…In aligner therapy, the precision of tooth movements in the setup is of utmost importance, as the fit between the aligner and the tooth surface affects the transmission of orthodontic force and the onset of tooth movement [ 17 , 18 , 19 ]. Inaccuracies in the setup must be considered in addition to other critically discussed inaccuracies in aligner fabrication, such as model manufacturing [ 20 , 21 ] and thermoforming [ 22 ]. In 3D-printed models for aligner therapy, deviations of less than 0.25 mm compared to the virtual models are necessary [ 23 ].…”

Three-Dimensional-Printed Customized Orthodontic and Pedodontic Appliances: A Critical Review of a New Era for Treatment

“…Three articles focused on the 3D printing fabrication of appliances that included bands. One introduced 3D printing of orthodontic brackets, and three looked at direct-printed clear aligners [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ].…”

“…In addition, the expected force decay induced by repeated insertion of the clear aligners is reduced and a constant orthodontic force can be maintained. Furthermore, its geometric stability at high temperatures and its shape memory properties provide advantages for clinical application [ 13 , 14 , 15 ] ( Figure 8 ). Printed aligner manufacturing follows a specific protocol that should be accurately followed.…”

Integrated manufacturing of direct 3D-printed clear aligners

“…Grey literature findings enlist 3Shape Clear Aligner Studio (3Shape, Copenhagen, Denmark), Blue Sky Plan (Blue Sky Bio, Libertyville, Illinois, USA), ArchFrom (Sunnyvale, Calif., USA), uDesign 7 (uLab Systems Inc., Memphis, USA), and CS Model+ (Carestream Dental, Atlanta, USA). With MeshMixer (Autodesk Inc, San Rafael, Calif., USA), the design can be prepared for a solitary selected model (23,24). The output data can be transferred to the slicing software to proceed with the 3D printing of clear aligners.…”