ABSTRACT
Full arch models play an important role in clear aligner orthodontic therapy and the preparation of prosthodontic appliances. Three dimensional (3D) printed full arches are very popular with the benefit of easy production and good mechanical properties for fabricating clear aligner. However, the accuracy of 3D printed full arches after long storage have not been proved yet. The objective of this study was to estimate the long-term accuracy of 3D full arches produced by the four types of 3D printers (stereo-lithography apparatus (SLA), digital light projector (DLP), Polyjet™ (POL), and fused deposition modeling (FDM)) following an accelerated aging treatment. The highest accuracy was produced by POL (before treatment) and SLA (after treatment) group, respectively. Comparisons between absolute mean trueness for the 3D printed full arches before and after treatment indicated that the deviation of the trueness values of FDM group were significantly higher than those of other experimental groups (p<0.05). In addition, all trueness relative errors for FDM group were greater than 0.04 after treatment, which was high compared to those of other experimental groups. Therefore, the long-term storage of full arches fabricated by FDM type 3D printer is not recommended and the 3D printed full arches should be used immediately whenever possible.
Subject(s)
Aging , Printing, Three-DimensionalABSTRACT
The purpose of this study was to evaluate the shear bond strengths between various hybrid computer-aided design (CAD)/computer-aided manufacturing (CAM) restorative materials and repairing resin. Two resin network-based hybrid (Lava Ultimate and Polyglass), one ceramic framework-based hybrid (Enamic), and one zirconia (Zenotec Zr bridge) CAD/CAM restorative materials were used in this study. The shear bond strength test and failure modes of four experimental groups designated LUS (Lava Ultimate), ENA (Enamic), PGB (Polyglass), and ZBR (zirconia control group) were characterized in this study. The hybrid CAD/CAM restorative materials showed stronger shear bond strengths in the sequence of PGB, LUS, and ENA (P < 0.05). The shear bond strengths of PGB and LUS groups showed significantly higher than those of ZBR (P < 0.05), while ENA did not show any significant difference from ZBR (P < 0.05). The PEG and LUS groups mostly exhibited cohesive failure, but the ENA and ZBR groups predominantly showed adhesive failure. Therefore, resin network-based hybrid CAD/CAM restorative materials such as Lava Ultimate and Polyglass should be more useful for intra-oral repairs.