Influence of alumina air-abrasion for highly translucent partially stabilized zirconia on flexural strength, surface properties, and bond strength of resin cement

Abstract Objective This study aims to evaluate the influence of different air-abrasion pressures and subsequent heat treatment on the flexural strength, surface roughness, and crystallographic phases of highly translucent partially stabilized zirconia (Y-PSZ), and on the tensile bond strength of resin cement to Y-PSZ. Methodology Fully sintered zirconia specimens were ground with SiC paper (control) and/or air-abraded with 50 µm particles of alumina at 0.1, 0.15, 0.2, or 0.3 MPa or left as-sintered. After air-abrasion at 0.2 MPa (0.2AB), additional specimens were then heated to 1500°C, and held for one hour at this temperature (0.2AB+HT1h). Flexural strength and surface roughness were evaluated. Crystalline phase identification was also carried out using X-ray diffraction. Bonded zirconia specimens with self-adhesive resin cement were stored in distilled water at 37°C for 24 h, either with or without aging (thermal cycling 4-60°C/20000). Results were analyzed statistically by ANOVA and Tukey-Kramer tests. Results The flexural strength decreased with the increase in air-abrasion pressure, while in contrast, the surface roughness increased. The lowest flexural strength and the highest roughness value were found for the 0.2AB and 0.3AB groups, respectively. All groups contained cubic-, tetragonal ( t )-, and rhombohedral ( r )-ZrO2 phases with the exception of the as-sintered group. Upon increasing the air-abrasion pressure, the relative amount of the r -ZrO2 phase increased, with a significant amount of r -ZrO2 phase being detected for the 0.2AB and 0.3AB groups. The 0.2AB+HT1h group exhibited a similar flexural strength and t -ZrO2 phase content as the as-sintered group. However, the 0.2AB group showed a significantly higher tensile bond strength (p<0.05) than the 0.2AB+HT1h group before and after aging. Conclusion Micromechanical retention by alumina air-abrasion at 0.2 MPa, in combination with chemical bonding of a resin to highly translucent Y-PSZ using a MDP-containing resin cement may enable durable bonding.

**研究目的**：本研究旨在评估不同喷砂压力及后续热处理对高透部分稳定氧化锆（Y-PSZ）的弯曲强度、表面粗糙度与晶相的影响，以及树脂水门汀与Y-PSZ之间的拉伸粘结强度。**研究方法**：将完全烧结的氧化锆试样以碳化硅砂纸（SiC paper）打磨作为对照组，或使用50 µm氧化铝（alumina）颗粒分别以0.1、0.15、0.2、0.3 MPa的压力进行喷砂处理，或保留烧结原样。针对经0.2 MPa喷砂处理的试样（0.2AB组），额外将部分试样加热至1500℃并保温1 h（0.2AB+HT1h组）。对各组试样开展弯曲强度与表面粗糙度检测，同时采用X射线衍射（X-ray diffraction）进行晶相鉴定。使用自粘结树脂水门汀（self-adhesive resin cement）粘结的氧化锆试样，分别在37℃蒸馏水中储存24 h，其中一半进行老化处理（热循环：4~60℃，20000次），另一半不做老化处理。采用方差分析（ANOVA）与Tukey-Kramer检验对结果进行统计学分析。**研究结果**：随着喷砂压力升高，试样的弯曲强度下降，而表面粗糙度则随之升高。0.2AB组的弯曲强度最低，0.3AB组的表面粗糙度最高。除烧结原样组外，其余各组均含有立方相、四方（t）相与菱方（r）相氧化锆。随着喷砂压力升高，菱方相氧化锆的相对含量逐渐增加，0.2AB组与0.3AB组可检测到大量菱方相氧化锆。0.2AB+HT1h组的弯曲强度与四方相氧化锆含量均与烧结原样组相近。而在老化处理前后，0.2AB组的拉伸粘结强度均显著高于0.2AB+HT1h组（p<0.05）。**研究结论**：采用0.2 MPa氧化铝喷砂形成的微机械固位，结合使用含MDP的树脂水门汀实现树脂与高透Y-PSZ之间的化学粘结，可获得耐久的粘结效果。