BEGO Implant Systems (Germany)

ABSTRACTInvestigating the mechanical properties and dimensional accuracy of 3D printed parts is an important step towards achieving optimum printing conditions. This condition, which leads to the fabrication of parts with appropriate mechanical properties and accuracy, is achieved by studying the effect of different process parameters on the final structure. In this work, Response Surface Methodology (RSM) was employed to design specified experiments to investigate the effects of layer thickness, printing orientation and delay, on the compressive strength and dimensional error of the parts. The results show that an increase in the delay time in X orientation results in better binder spreading and uniformity followed by improvement in the compression strength. Furthermore, more binder spreads in the vertical direction leads to the higher dimensional error in the Z direction. The results proved that the RSM provides a time and cost-efficient design to print the prototypes with optimum strength and dimensional error.

Direct laser interference patterning (DLIP) is used to produce periodic line-like patterns on titanium surfaces. An Nd:YAG laser operating at 532 nm wavelength with a pulse duration of 8 ns is used for the laser patterning process. The generated periodic patterns with spatial periods of 5, 10, and 20 µm are produced with energy densities between 0.44 and 2.6 J cm-2 with a single laser pulse. With variation of energy density, different shapes of the arising topography are observed due to the development of the solidification front of the molten material at the maxima positions. Characterization of the surface chemistry shows that the DLIP treatment enhances the content of nitrogen of the titanium reactive layer from 3.9% up to 23.4%. The structural analysis near the titanium surface shows no changes in microstructure after the laser treatment. Contact angles between 65° and 79° are measured on both structured and turned reference surfaces. Cell viability of human osteoblasts on line-like patterned surfaces after 7 d in cultivation medium is 16% higher compared to the grit-blasted and acid-etched references. Finally, the possibility of patterning complex 3D dental implants is shown.