Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju 61186, Republic of Korea.
School of Materials Science and Engineering, Chonnam National University, Gwangju, 61186, Republic of Korea.
Dent Mater. 2019 May;35(5):e97-e106. doi: 10.1016/j.dental.2019.02.001. Epub 2019 Mar 2.
The objectives of the present study were: (1) to analyze the dispersion and optical properties of suspensions with various volume fractions of zirconia, and (2) to assess the influence of zirconia volume fraction on the microstructure and physical properties of products produced by the additive manufacturing and sintering process.
Zirconia specimens were fabricated by an additive manufacturing technique using a DLP (digital light processing) system. The zirconia suspensions were divided into six groups based on zirconia volume fraction within the range of 48-58vol%.
The maximum volume fraction of zirconia in suspensions possible for printing was 58vol%. The cure depth of the zirconia suspensions decreased as the volume fraction increased. The cure depth was greater than 100μm after 15s photocuring in all groups. Geometrical overgrowth tended to increase gradually as the volume fraction of zirconia increased within the range of 28.55-36.94%. The 3-point bending strength of the specimens increased as the volume fraction of zirconia in the suspension increased, reaching a maximum value of 674.74±32.35MPa for a volume fraction of 58vol%. Cracks were observed on the surfaces of zirconia specimens and these cracks increased in number as zirconia volume fraction decreased.
In this experiment, the viscosity of zirconia suspensions sharply increased from a volume fraction of 54vol%. Because of the very high viscosity, 58vol% was the maximum volume fraction possible for additive manufacturing. After polymerization, all specimens showed some distortion due to geometrical overgrowth. The maximum 3-point bending strength was 674.74±32.35MPa for a volume fraction of 58vol%. But the maximum strength of sintered zirconia prepared by additive manufacturing is inferior to that of conventionally sintered zirconia.
本研究的目的是：（1）分析不同氧化锆体积分数的悬浮液的分散和光学特性；（2）评估氧化锆体积分数对添加剂制造和烧结工艺生产的产品的微观结构和物理性能的影响。
使用 DLP（数字光处理）系统通过添加剂制造技术制造氧化锆样品。将氧化锆悬浮液分为六组，根据氧化锆体积分数在 48-58vol%范围内。
可用于打印的氧化锆悬浮液的最大体积分数为 58vol%。随着体积分数的增加，氧化锆悬浮液的固化深度减小。在所有组中，经过 15s 的光固化后，固化深度大于 100μm。随着氧化锆体积分数在 28.55-36.94%范围内逐渐增加，几何过度生长趋于逐渐增加。随着悬浮液中氧化锆体积分数的增加，样品的 3 点弯曲强度增加，当体积分数为 58vol%时达到最大值 674.74±32.35MPa。在氧化锆样品表面观察到裂纹，随着氧化锆体积分数的降低，裂纹数量增加。
在本实验中，氧化锆悬浮液的粘度从体积分数为 54vol%急剧增加。由于粘度非常高，58vol%是添加剂制造的最大体积分数。聚合后，由于几何过度生长，所有样品都显示出一些变形。体积分数为 58vol%时，最大 3 点弯曲强度为 674.74±32.35MPa。但是，通过添加剂制造制备的烧结氧化锆的最大强度不如传统烧结氧化锆。
