Aim: For manufacturing orthodontic aligner in a complete digital workflow, 3D-printing of dental models is necessary. The available printing technologies have advantages and disadvantages. The aim was to optimize model printing using FFF printers with respect to the materials used.
Material and Methods: For the study, a patient model with buccal and lingual attachments was created using OnyxCeph (Image Instruments GmbH, Chemnitz) and exported after mesh optimization. In addition, a test plate with nine defined parameters was selected for the acquisition of inner- and outer dimensions and surface detail quality. All objects were printed with a TEVO Tornado (TEVO 3D Electronic Technology Co. Ltd., China) with a layer thickness of 150 µm under otherwise identical conditions and parameters. A total of 11 materials were tested. Both the models and test plates were measured with a digital caliper and a VHX-6000 digital microscope (Keyence Deutschland GmbH, Neu-Isenburg) and the surfaces assessed. Aspects of sustainability were also included in the assessment.
Results: Four of the 11 materials showed favourable properties under these test conditions, both according to metric analyses and with regard to the surface quality. Other materials exhibited odor development or significant warping. In some cases, this could be avoided by using a differently designed printer with heated chamber. The accuracy is acceptable for all materials used, taking into account the measurement accuracy.
Conclusions: PETG (glycol modified polyethylene terephthalate, PLA (polylactide), modified biopolymers, and lignin-based filaments can be recommended as the most suitable materials. The last three are preferable from our point of view due to their biodegradability. Modified biopolymers (e.g. Biofil PowR) and lignin filaments (e.g. GreenTec Pro) can be seen as the best printing materials.
Keywords: FFF-3D-printing, aligner, filament
