An Update on 3D-printed Orthodontic Aligners

Abstract

Clear Aligner Treatment (CAT) is an orthodontic technique used to align teeth with removable and scarcely visible appliances. Conventionally, these are produced through the process of thermoforming. The inherent disadvantages of thermoforming include increased surface roughness leading to plaque accumulation, compromised biomechanics due to a reduction in force delivered and flexure of the aligner, and altered mechanical properties, such as increased opacity, water sorption, and hardness. Direct Three-dimensional (3D)-printed aligners, or Direct Printed Aligners (DPA), introduce a new frontier to aligner technology and are a recent addition to the ever-improving field of orthodontics. Through 3D printing, the various disadvantages of thermoformed aligners like surface roughness, extent and definition of aligner borders, undercuts, and differential thickness of the aligner can be controlled to enhance the accuracy of aligner fit with lesser reliance on attachments. 3D printing of aligners is more environmentally friendly since there is no subtractive process for thermoforming or post-processing of the TA. Various methods of 3D printing, such as selective laser melting, selective laser sintering, Stereolithography (SLA), and Digital Light Processing (DLP), can be applied to the printing of clear aligners. Challenges in printing primarily involve maintaining transparency and designing support during the printing process. The present review aimed to include a detailed description of all aspects of direct 3D-printed aligners.