六种玻璃离子粘固剂断裂模式的比较

目的采用赫兹压痕实验,研究不同类型玻璃离子粘固剂的断裂模式。方法选取6种玻璃离子粘固剂材料(A~D为酸反应固化型,其中A、B无加强成分,C为银粉加强,D为陶瓷加强;E、F为树脂改良型)制作圆盘形试件各10个,直径为10mm,厚度为2mm。置于玻璃纤维加强尼龙6,6基底上,通过直径为20mm的加载头进行静态加载,记录初始断裂载荷,扫描电镜观察试件断裂模式。结果材料A、B、C、D均表现为相似的脆性断裂模式,材料E、F多数试件为局部不完全断裂。材料A~F的初始断裂载荷分别为(258.86±10.49)、(230.88±21.66)、(281.90±25.39)、(282.11±9.60)、(756.67±83.50)和(1148.00±147.78)N,前4种与后2种间差异有统计学意义(P<0.05)。结论玻璃离子粘固剂的固化类型决定其断裂模式;金属或陶瓷加强成分增加试件承受载荷能力的效果不大。

Comparison of the failure mode of various types of glass ionomer cements

OBJECTIVE: To investigate the failure mode of various types of glass ionomer cements by Hertzian indentation test. METHODS: Discs of 10 mm diameter and 2 mm thickness were prepared for six glass ionomer cement products (A-D: conventional type setting through an acid-base chemical reaction, A and B without reinforcement, C with silver reinforcement, D with ceramic reinforcement; E and F: resin-modified type), ten for each. These were tested on top of glass-reinforced polyamide-nylon 6, 6 substrates by a universal testing machine, loading centrally with a 20 mm diameter ball. Load at the first crack was recorded. Failure mode was observed under scanning electron microscope. RESULTS: The former four products presented typical brittle fracture, while the latter two usually fractured incompletely. The failure loads at the first crack of the six glass ionomer cements were (258.86 +/- 10.49), (230.88 +/- 21.66), (281.90 +/- 25.39), (282.11 +/- 9.60), (756.67 +/- 83.50) and (1 148.00 +/- 147.78) N, respectively. Significant difference was found between the former four and the latter two products. CONCLUSIONS: The type (setting mode) of glass ionomer cement controls its failure mode. Inclusion of metallic or ceramic filler has little effect on increasing the load bearing capacity of glass ionomer cement.