“…The accuracy of 3D-printed retainers and aligners has been evaluated with reference to printing technology [ 26 ], printing material [ 27 , 28 , 29 ], printing orientation [ 30 , 31 , 32 ], and post-printing protocols [ 30 ]. In addition, thickness [ 27 ], fit [ 33 , 34 ], mechanical, and thermo-mechanical properties of 3D-printed aligners and retainers have been investigated [ 28 , 29 , 30 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ].…”