Authors : T. Giffin Mathew; Nitin Dungarwal; Trivedi Rutvik; Shyama Deora; Meghna Sharma; Kshemya Parmar; Divya Singh; Neha Agarwal; Nisha Kalal; Mrinal Singh

Volume/Issue : Volume 11 - 2026, Issue 9 - September

Google Scholar : https://tinyurl.com/53m647pn

DOI : https://doi.org/10.38124/ijisrt/26sep1421

Note : A published paper may take 4-5 working days from the publication date to appear in PlumX Metrics, Semantic Scholar, and ResearchGate.

Abstract : Clear aligner therapy has shifted from being almost exclusively outsourced to commercial laboratories toward an in-house, or “chairside,” model in which the clinician controls scanning, digital treatment planning, 3D printing, and thermoforming within the practice itself. This places material selection, manufacturing technology, and biomechanical design directly in the orthodontist’s hands, yet practical guidance on translating this control into predictable tooth movement remains scattered across the literature. This narrative review consolidates current evidence on in-house clear aligner systems, covering the advantages and disadvantages of in-house fabrication relative to outsourced systems; the three principal in-house workflows - thermoformed, direct 3D-printed, and hybrid/multilayer aligners; the manufacturing technologies used to produce them, including fused deposition modelling (FDM) and vat-polymerization printing (stereolithography, digital light processing, and masked stereolithography/LCD); the mechanical behavior of the three thermoplastics most commonly used in-house - thermoplastic polyurethane (TPU), polyethylene terephthalate glycolmodified (PETG), and crystallized/co-polyester PET (PET-C) - framed through a wire analogy familiar to orthodontists, with particular attention to stress relaxation and force decay; attachment (“engager”) design and bonding protocols used to programme specific tooth movements; and severity-based correction algorithms for crowding and for vertical, transverse, and anteroposterior discrepancies. The review also outlines the practical problems encountered in day-to-day in-house practice, including force-calibration errors, fit and marginal-adaptation issues, under-delivery of planned interproximal reduction and proclamation, and staff-training demands. Taken together, the evidence indicates that inhouse aligner therapy can reduce turnaround time and increase clinician control, but that its success depends on a movement-specific approach to material selection, realistic mid-treatment monitoring, and a working understanding of how aligner materials behave mechanically after activation — knowledge that has traditionally resided with the outsourced laboratory rather than the clinician.

Keywords : Clear Aligners; In-House Aligners; Chairside Orthodontics; 3D Printing; Thermoforming; Stress Relaxation; Aligner Attachments; Malocclusion; Orthodontic Biomechanics.

References :

1. Bichu YM, Alwafi A, Liu X, Andrews J, Ludwig B, Bichu AY, Zou B. Advances in orthodontic clear aligner materials. Bioact Mater. 2023;22:384-403. doi:10.1016/j.bioactmat.2022.10.006.
2. Cenzato N, Di Iasio G, Martín Carreras-Presas C, Caprioglio A, Del Fabbro M. Materials for Clear Aligners—A Comprehensive Exploration of Characteristics and Innovations: A Scoping Review. Appl Sci. 2024;14(15):6533. doi:10.3390/app14156533.
3. Narongdej P, Hassanpour M, Alterman N, Rawlins-Buchanan F, Barjasteh E. Advancements in Clear Aligner Fabrication: A Comprehensive Review of Direct-3D Printing Technologies. Polymers. 2024;16(3):371. doi:10.3390/polym16030371.
4. Tartaglia GM, Mapelli A, Maspero C, Santaniello T, Serafin M, Farronato M, Caprioglio A. Direct 3D Printing of Clear Orthodontic Aligners: Current State and Future Possibilities. Materials (Basel). 2021;14(7):1799. doi:10.3390/ma14071799.
5. Grassia V, Ronsivalle V, Isola G, Nucci L, Leonardi R, Lo Giudice A. Accuracy (trueness and precision) of 3D printed orthodontic models finalized to clear aligners production, testing crowded and spaced dentition. BMC Oral Health. 2023;23:352. doi:10.1186/s12903-023-03025-8.
6. Wang Y, Long H, Zhao Z, et al. Expert consensus on the clinical strategies for orthodontic treatment with clear aligners. Int J Oral Sci. 2025;17:19. doi:10.1038/s41368-025-00350-2.
7. Tamburrino F, D’Antò V, Bucci R, Alessandri-Bonetti G, Barone S, Razionale AV. Mechanical Properties of Thermoplastic Polymers for Aligner Manufacturing: In Vitro Study. Dent J (Basel). 2020;8(2):47. doi:10.3390/dj8020047.
8. Liu M, Wang Y, Bian C, Han Y, Qin X, Sun J, Bai Y, Zhang N. Comparative mechanical performance of thermoplastic materials for clear aligners under simulated oral conditions. Korean J Orthod. 2025;55(5):380-391. doi:10.4041/kjod25.094.
9. D’Antò V, Oliva G, Nieri M, et al. Indications and limits of clear aligner therapy: an international modified Delphi consensus study. Prog Orthod. 2025;26:28. doi:10.1186/s40510-025-00575-1.
10. Šimunović L, Brenko L, Marić AJ, Meštrović S, Haramina T. Rheology of Dental Photopolymers for SLA/DLP/MSLA 3D Printing. Polymers. 2025;17(19):2706. doi:10.3390/polym17192706.
11. Lombardo L, Martines E, Mazzanti V, Arreghini A, Mollica F, Siciliani G. Stress relaxation properties of four orthodontic aligner materials: A 24-hour in vitro study. Angle Orthod. 2017;87(1):11-18. doi:10.2319/113015-813.1.
12. Elkholy F, Schmidt S, Schmidt F, Amirkhani M, Lapatki BG. Force decay of polyethylene terephthalate glycol aligner materials during simulation of typical clinical loading/unloading scenarios. J Orofac Orthop. 2023;84:189-201. doi:10.1007/s00056-021-00364-5.
13. Nanda R, Castroflorio T, Garino F, Ojima K, editors. Principles and Biomechanics of Aligner Treatment. 1st ed. Elsevier; 2021.
14. Fang D, Zhang N, Chen H, Bai Y. Dynamic stress relaxation of orthodontic thermoplastic materials in a simulated oral environment. Dent Mater J. 2013;32(6):946-951. doi:10.4012/dmj.2013-131.
15. Cremonini F, Brucculeri L, Pepe F, Palone M, Lombardo L. Comparison of stress relaxation properties between 3-dimensional printed and thermoformed orthodontic aligners: A pilot study of in vitro simulation of two consecutive 8-hours force application. APOS Trends Orthod. 2024;14:225-234. doi:10.25259/APOS_201_2023.
16. Cui X, Li F, et al. Effects of simulated intraoral temperatures and wet environments on the stress relaxation properties of thermoplastic aligner materials. BMC Oral Health. 2025;21:23. doi:10.1186/s13005-025-00497-7.
17. Sair S, Chkhayess D, El Quars F, El Mabrak A. Shape, Position, Dimension of Attachments in Clear Aligners: A Systematic Review. Open Access Library Journal. 2026;13:e14791. doi:10.4236/oalib.1114791.
18. Sultanoğlu E, Gürel HG, Gülyurt M. The Effects of Different Attachment Types and Positions on Rotation Movement in Clear Aligner Treatments: A Finite Element Analysis. Cureus. 2024;16(8):e66273. doi:10.7759/cureus.66273.
19. Chen PY, Huang HL, Yu JH, Hsu JT. Optimal positions of clear aligner attachments to achieve lower canine tipping and bodily movement using finite element analysis. J Dent Sci. 2024;19(4):2007-2017. doi:10.1016/j.jds.2024.07.005.
20. Peh J, Chong H, Meade MJ. Interproximal reduction with clear aligner therapy: A scoping review. Semin Orthod. 2026;32(1):91-103. doi:10.1053/j.sodo.2025.03.004.
21. Fiori A, Minervini G, Nucci L, d’Apuzzo F, Perillo L, Grassia V. Predictability of crowding resolution in clear aligner treatment. Prog Orthod. 2022;23:43. doi:10.1186/s40510-022-00438-z.
22. Gandedkar NH, Darendeliler MA. Space gaining in orthodontic treatment planning: The SPEED-L decision-making framework. Semin Orthod. 2026;32(3):568-587. doi:10.1053/j.sodo.2025.10.008.
23. Pozzan L, Bertolami V, Gabbana B, Morona J, Belašič Zibar T, Turco G, Porrelli D, Contardo L. Mechanical Properties of Thermoplastic Materials for Clear Orthodontic Aligners: A New Three-Dimensional Experimental Setting. Orthod Craniofac Res. 2025. doi:10.1111/ocr.70067.