Clinical research and clinical treatment cases
Numerous scientific articles validate the advantages of direct printing technology for producing orthodontic aligners with shape-memory polymers. We have selected some of these articles for you to explore in this section. If you would like more information, please contact us. We will be happy to provide you with further details.
Nature Scientific Reports
A study on the compressive strength of three-dimensional direct printing aligner material for specific designing of clear aligners
This study aimed to evaluate and compare the compressive strength of three-dimensional direct printing aligners (3DPA) with that of conventional thermo-forming aligners (TFA) to determine their clinical applicability.
Conclusions:
" 3DPA technology enables precise modifications in the shape and inner thickness at specific dental sites, including the creation of ridges in targeted areas, of aligners. These alterations enhance the biomechanical capability of aligners to exert selective forces necessary for desired tooth movement while reducing the number of attachments, thereby demonstrating the clinical potential of 3D-printed aligners in orthodontic treatment".​
https://www.nature.com/articles/s41598-025-86687-4
Published: January 2025
Journal Of Clinical Orthodontics
Direct-Printed Aligners: A Clinical Status Report
Research groups, scientists, and companies have recently been moving away from vacuum-forming processes, instead investigating new materials for 3D-printing of aligner shells. Among these materials, Graphy’s Tera Harz TC-85, which was approved in 2022 by the U.S. Food and Drug Administration, the European Union (CE marking), and other official bodies, has gained routine use in offices worldwide.
Studies have demonstrated that 3D-printed aligners can successfully treat mild crowding, with an accuracy that compares favorably to that of conventional aligners. When used in conjunction with interproximal reduction, direct-printed aligners can also predictably and effectively correct moderate crowding. Furthermore, their customizability makes these aligners ideal for unexpected complications or support during the finishing stages of difficult cases
https://www.jco-online.com/archive/2024/11/658-direct-printed-aligners-a-clinical-status-report/
Published: November 2024
Journal of Orthodontic Science
The new additive era of orthodontics: 3D‑printed aligners and shape memory polymers—the latest trend—and their environmental implications.
The article highlights several key points, including:
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The many benefits of 3D printed aligners.
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Results from a cytotoxicity and estrogenicity study of direct-printed aligners showed that they were non-toxic to human gingival fibroblasts and did not affect intracellular reactive oxygen species levels after 14 days of water aging.
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Reducing waste and environmental impact by eliminating the need for dental models through direct aligner printing.
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The technology can potentially improve clear aligner therapy by making it more efficient, faster, more comfortable, and less prone to complications for patients.
Published: November 2024
Materials (Basel)
Towards Sustainable Orthodontics: Environmental Implications and Strategies for Clear Aligner Therapy
This article examines the environmental impact of the traditional method of aligner production, known as thermoforming, and highlights direct 3D printing of aligners as a breakthrough solution. This innovative approach not only eliminates the waste generated by thermoforming and 3D printing of physical models but also reinforces a commitment to more sustainable operational practices.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11395928/
Published: August 2024
Cureus Part of Springer Nature
Class II Correction and Crowding Treatment Using In-House Direct Printed Clear Aligners: A Literature Review and Case Report
This literature review and case report specifically focus on the effectiveness of directly printed clear aligners in treating Class II malocclusions and crowding. The review and case report highlight the increasing importance of directly printed clear aligners in modern orthodontics and provide clinicians with a valuable tool to effectively address complex malocclusions and crowding while also meeting patient needs for discretion and comfort.
Article Conclusion: In-house production of direct-printed aligners offers many benefits for orthodontists and their patients, including shape memory effect, light force, biocompatibility, better physical and mechanical properties, as well as improved accuracy, fit, and clinical feasibility, and represents a promising advancement in orthodontic treatment.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11333988/
Published: July 2024
Journal Of Clinical Orthodontics
In-House 3D-Printed Shape Memory Aligners for Retreatment after Fixed Retainer Failure
"This case underscores the efficacy of customized, technologically driven approaches in treating complex cases. The unique properties of 3D-printed aligners with shape memory allowed us to save a lower lateral incisor with an impaired periodontium and effectively manage protruded lower incisors and a proclined lower canine without the need for additional skeletal anchorage. As the body of scientific and clinical knowledge about 3D-printed aligners continues to grow, they are likely to become a transformative alternative to standard thermoformed aligners and conventional fixed appliances".
Published: June 2024
Virtual and Physical Prototyping
Force system of 3D-printed orthodontic aligners made of shape memory polymers: an in vitro study.
Compared to conventional thermoformed aligners, 3D-printed aligners using Tera Harz TC-85 demonstrate the ability to deliver orthodontically compatible forces for orthodontic tooth movement in experimental settings. Unlike thermoformed aligners, 3D-printed aligners provide improved control over thickness.
Highlights
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The 3D-printed Tera Harz TC-85 resin revolutionises aligner production.
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Tera Harz TC-85 aligners generate forces within the orthodontic accepted range.
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Shape recovery of TC-85 can enable adaptability and larger incremental step size.
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The 3D printing offers greater control over aligner design and thickness.​
https://www.tandfonline.com/doi/full/10.1080/17452759.2024.2361857
Published: June 2024
Royal Society of Chemistry
The global burden of plastics in oral health: prospects for circularity, sustainable materials development and practice
The versatility and widespread use of plastics, combined with the large volume of products consumed daily by the general population and dentists to maintain and restore oral health, positions dentistry as a significant contributor to the global plastic waste crisis. This article, on page 887, cites how the production of clear aligners through the thermoforming workflow contributes to the environmental burden.
The disruptive technology of directly printing clear aligners with shape memory polymers brings benefits to orthodontic treatment and represents a sustainable and environmentally friendly practice, in line with UN Sustainable Development Goal 3 (Good Health and Well-Being). At the same time, Goal 8 (Decent Work and Economic Growth) and Goal 13 (Climate Action) underscore the urgency of transitioning to sustainable polymers and circular economy practices to reduce the environmental footprint of modern dentistry.
https://pubs.rsc.org/en/content/articlepdf/2024/su/d3su00364g
Published: April 2024
Journal of the Mechanical Behavior of Biomedical Materials
Physiochemical and mechanical characterisation of orthodontic 3D printed aligner material made of shape memory polymers (4D aligner material)
A Clinical relevance: The 3D printed aligner material with shape memory characteristics (4D aligner) has revolutionized the orthodontic aligner field. It showed mechanical properties more suitable for orthodontic treatment than thermoforming materials. Additionally, it offers enhanced control over aligner design and thickness, while optimizing the overall workflow. It also minimizes material wastage, and reduces production expenses.
https://www.sciencedirect.com/science/article/pii/S1751616123006914?via%3Dihub
Published: February 2024
Polymers (Basel)
Advancements in Clear Aligner Fabrication: A Comprehensive Review of Direct-3D Printing Technologies
As the dental industry progresses toward 4D printing, the future promises even more effective treatments and improved quality of life for patients. With the continued implementation of additive manufacturing, clear aligners are poised to revolutionize the treatment of minor malocclusions and positively impact the lives of numerous future patients.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10856925/
Published: February 2024
Preprints.org
Sustainability in Healthcare Sector: The Dental Aligners Case
This comparative study evaluated the environmental impacts associated with two manufacturing processes for dental aligners: thermoforming and direct 3D printing.
In conclusion, the results of this study suggest that direct 3D printing of dental aligners has a lower environmental impact than thermoforming. This advantage is primarily attributed to the efficient use of materials, reduced energy consumption, and minimized waste generation associated with direct 3D printing.
The reduction in the amount of raw materials required in the direct printing process contributes to a significant reduction in the total amount of waste generated, underscoring the environmental benefits of this innovative technique.
Published: November 2023
Journal of Bioactive Materials
ADVANCES IN ORTHODONTIC CLEAR ALIGNER MATERIALS
Abstract
Rapid technological improvements in biomaterials, computer-aided design (CAD) and manufacturing (CAM) have endorsed clear aligner therapy (CAT) as a mainstay of orthodontic treatment, and the materials employed for aligner fabrication play an all-important role in determining the clinical performance of clear aligners. This narrative review has attempted to comprehensively encompass the entire gamut of materials currently used for the fabrication of clear aligners and elucidate their characteristics that are crucial in determining their performance in an oral environment.
https://www.sciencedirect.com/science/article/pii/S2452199X22004303
Published: April 2023
Journal of Korean Dental Science
Force Assessment of Thermoformed and Direct-printed Aligners in a Lingual Bodily Movement of a Central Incisor Over Time: A 14-day In Vitro Study
Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
The force levels of three different aligner materials (Zendura, ATMOS, TC-85) on a labially displaced central incisor over 14 days were measured. Total 90 aligners were tested. Comparisons were made for baseline measurements to 7-days and 14-days; both comparisons showed statistically significant change from the baseline force level. Aligners printed with TC-85 material generated lower, more consistent, and closer to the ideal forces, with fewer side effects.
https://www.dbpia.co.kr/pdf/pdfView.do?nodeId=NODE11447909
Published: March 2023
Journal of Aligner Orthodontics
Shape memory aligners: A new dimension in aligner orthodontics
To overcome the limitations of the conventional vacum thermoforming manufacturing process, the method of direct 3D printing of aligners has been developed. This presentes more advantages than simply avoiding a two-step process, whereby the model to be printed first before the aligners are thermoformed. The shape memory function offers new and improved biomechanical options. This article presents the new direct 3D printed aligner material from Graphy (Seoul, South Korea) and a patient example demonstrating the course of treatment with the new material.
Published: February 2023
Frontiers in Dental Medicine
Integrated manufacturing of direct 3D-printed clear aligners
With direct 3D-printing technology for clear aligner manufacturing, the errors related to the intermediate steps of making thermoformed aligners, such as model formation, molding, removal, and finishing, can be bypassed. Thus, it can be anticipated that aligner production will impart better precision between the initial set-up and the expected outcome. Establishing the offset for various printer and resin combinations will offer a greater advantage to control the desired and resultant thicknesses. Dimensionally controlled differential thickness can be programmed and processed according to the individual requirements of the case, resulting in better force application. The production can be with shorter supply chains, significantly shorter lead times, and lower costs. Since the thermoforming workflow generates a significant amount of non-biodegradable waste such as petroleum-based polymers used in model fabrication, the direct 3D-printing technique bestows a more environmentally friendly choice in the employment of digital technology.
Published: January 2023
Progress in Orthodontics
FORCE PROFILE ASSESSMENT OF DIRECT-PRINTED ALIGNERS VERSUS THERMOFORMED ALIGNERS AND THE EFFECTS OF NON-ENGAGED SURFACE PATTERNS
Conclusions Direct-printed aligners can deliver biologically compatible forces for orthodontic tooth movement in an in vitro setting. In contrast to thermoformed aligners, the forces delivered by direct-printed aligners may demonstrate improved ability to deliver forces within the traditionally accepted range of optimum forces for tooth movement. The study demonstrates that surface pattern did not alter the force profile of aligners. Further investigation of surface patterns, ribbing, and other features in direct-print aligners offers a new realm of opportunity in clear aligner research.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9705625/
Published: November 2022
American Journal of Orthodontics and Dentofacial Orthopedics
CYTOTOXICITY AND ESTROGENICITY OF A NOVEL 3-DIMENSIONAL PRINTED ORTHODONTIC ALIGNER
Conclusions
In conclusion, if any factors were released during the 14-day aging of 3D-printed aligners in water, these were not found to be cytotoxic for human gingival fibroblasts and did not affect their intracellular reactive oxygen species levels. Moreover, no estrogenic effects of these putative eluates were observed based on an E-screen assay.
https://www.sciencedirect.com/…/pii/S0889540622003961
Published: September 2022
The Korean Journal of Orthodontics
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.
Conclusions: This study showed greater trueness and precision of direct-printed aligners than thermoformed aligners.
https://pubmed.ncbi.nlm.nih.gov/35466087/
Published: July 2022
Nature Scientific Reports
THERMO-MECHANICAL PROPERTIES OF 3D PRINTED PHOTOCURABLE SHAPE MEMORY RESIN FOR CLEAR ALIGNERS
Abstract
To overcome the limitations of the conventional vacuum thermoforming manufacturing method, direct 3D printing of clear aligners has been developed. The present study investigated the thermo-mechanical and viscoelastic properties of a photocurable resin TC-85, which is a new material for the direct 3D printed clear aligners, comparing to a conventional thermoplastic material polyethylene terephthalate glycol…
https://www.nature.com/articles/s41598-022-09831-4
Published: April 2022
European Journal of Orthodontics
IN-HOUSE 3D-PRINTED ALIGNERS: EFFECT OF IN VIVO AGEING ON MECHANICAL PROPERTIES
Objective
To investigate alterations in the mechanical properties of in-house three-dimensional (3D) printed orthodontic aligners after intraoral ageing.
Materials and methods: Sixteen 3D-printed aligners (TC-85DAC resin, Graphy, Seoul, Korea)were used for the purpose of the study, which were divided into 10 control (not used) aligners and 6 materials retrieved from 4 patients after 1-week service (retrieved group)…
https://academic.oup.com/ejo/article/44/1/51/6265460
Published: January 2022
Dentistry Journal
Primary Evaluation of Shape Recovery of Orthodontic Aligners Fabricated from Shape Memory Polymer (A Typodont Study)
Elshazly et al. suggest that memory polymers could contribute to using fewer aligners. A single aligner produced with these materials could replace three aligners manufactured with conventional materials by allowing shape change within the same aligner. Reducing the number of aligners used for each treatment would decrease plastic waste and the energy consumption associated with their production, Consequently, aligners made of SMPs could be a promising future choice for orthodontic aesthetic treatment.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7998399/
Published: March 2021
Some examples of clinical cases using direct 3D printing of shape memory polymer aligners :
