Srikanth Ramanathan, Kosmac Tomaz, Della Bona Alvaro, Yin Ling, Zhang Yu
Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY 10010, USA.
Engineering Ceramics Department, Jozef Stefan Institute, Jamova 39, SI 1000 Ljubljana, Slovenia.
Dent Mater. 2015 Apr;31(4):435-42. doi: 10.1016/j.dental.2015.01.013. Epub 2015 Feb 14.
To examine the effects of glass infiltration (GI) and alumina coating (AC) on the indentation flexural load and four-point bending strength of monolithic zirconia.
Plate-shaped (12 mm × 12 mm × 1.0 mm or 1.5 or 2.0 mm) and bar-shaped (4 mm × 3 mm × 25 mm) monolithic zirconia specimens were fabricated. In addition to monolithic zirconia (group Z), zirconia monoliths were glass-infiltrated or alumina-coated on their tensile surfaces to form groups ZGI and ZAC, respectively. They were also glass-infiltrated on their upper surfaces, and glass-infiltrated or alumina-coated on their lower (tensile) surfaces to make groups ZGI2 and ZAC2, respectively. For comparison, porcelain-veneered zirconia (group PVZ) and monolithic lithium disilicate glass-ceramic (group LiDi) specimens were also fabricated. The plate-shaped specimens were cemented onto a restorative composite base for Hertzian indentation using a tungsten carbide spherical indenter with a radius of 3.2mm. Critical loads for indentation flexural fracture at the zirconia cementation surface were measured. Strengths of bar-shaped specimens were evaluated in four-point bending.
Glass infiltration on zirconia tensile surfaces increased indentation flexural loads by 32% in Hertzian contact and flexural strength by 24% in four-point bending. Alumina coating showed no significant effect on resistance to flexural damage of zirconia. Monolithic zirconia outperformed porcelain-veneered zirconia and monolithic lithium disilicate glass-ceramics in terms of both indentation flexural load and flexural strength.
While both alumina coating and glass infiltration can be used to effectively modify the cementation surface of zirconia, glass infiltration can further increase the flexural fracture resistance of zirconia.
研究玻璃渗透（GI）和氧化铝涂层（AC）对整体式氧化锆压痕弯曲载荷和四点弯曲强度的影响。
制备板状（12 mm×12 mm×1.0 mm或1.5或2.0 mm）和棒状（4 mm×3 mm×25 mm）的整体式氧化锆试件。除了整体式氧化锆（Z组）外，氧化锆整体在其拉伸表面进行玻璃渗透或氧化铝涂层处理，分别形成ZGI组和ZAC组。它们还在其上表面进行玻璃渗透，并在其下（拉伸）表面进行玻璃渗透或氧化铝涂层处理，分别形成ZGI2组和ZAC2组。为作比较，还制备了烤瓷贴面氧化锆（PVZ组）和整体式二硅酸锂微晶玻璃（LiDi组）试件。使用半径为3.2mm的碳化钨球形压头将板状试件粘结到修复性复合基底上进行赫兹压痕试验。测量氧化锆粘结表面压痕弯曲断裂的临界载荷。对棒状试件的强度进行四点弯曲评估。
氧化锆拉伸表面的玻璃渗透使赫兹接触中的压痕弯曲载荷增加32%，四点弯曲中的弯曲强度增加24%。氧化铝涂层对氧化锆的抗弯曲损伤性能无显著影响。在压痕弯曲载荷和弯曲强度方面，整体式氧化锆均优于烤瓷贴面氧化锆和整体式二硅酸锂微晶玻璃。
虽然氧化铝涂层和玻璃渗透均可用于有效改善氧化锆的粘结表面，但玻璃渗透可进一步提高氧化锆的抗弯曲断裂性能。
