[氢氟酸蚀刻时间和树脂粘结对二硅酸锂玻璃陶瓷弯曲强度的影响]

Ren Dong-feng, Luo Xiao-ping

Department of Prosthodontics, School of Stomatology, Nanjing University & Nanjing Stomatological Hospital, Nanjing 210008, China.

Zhonghua Kou Qiang Yi Xue Za Zhi. 2013 Aug;48(8):462-6.

OBJECTIVE

To analyze the effect of hydrofluoric acid(HFA) etching time and resin bonding on the flexural strength of IPS e.max® Press glass ceramic, and evaluate the efficacy of resin cements to seal the cracks of the etched ceramic.

METHODS

Two hundred and twenty-five bars (25.0 mm×3.0 mm×2.0 mm) were made from IPS e.max® Press ingots using lost-wax, hot-pressed ceramic fabrication technology and randomly divided into five groups, forty-five each.In each group, the surfaces of ceramic bars were etched by 9.5% HFA gel for 0, 20, 40, 60 and 120 s respectively. Three specimens from each group were selected to observe the microstructure by the field emission scanning electron microscope (FE-SEM). Then each group were randomly subdivided into two subgroups (n = 20).One subgroup were coverd with a thin (approximately 0.1 mm) layer of resin cement (Variolink N), whereas the other subgroup remained unaltered.Half of the specimens were stored in 37°C water bath for 24 h and the other half went through thermocycle 10 000 times before 3-point bending test to determine their flexural strength.Interfaces between resin cement and etched ceramic were examined with FE-SEM.

RESULTS

FE-SEM results showed that etching with HFA resulted in preferential dissolution of glass ceramic, and partially supported crystals within the glass matrix were lost with the increasing of etching time.FE-SEM indicated that resin cement sealed the cracks and defects and bonded tightly to etched ceramic surface. The mean flexural strength values of group 0, 20, 40, 60 and 120 s were (384 ± 33), (347 ± 43), (330 ± 53), (327 ± 67) , and (317 ± 41) MPa respectively. The mean flexural strength of each group except group 0 s increased significantly to (420 ± 31), (435 ± 50), (400 ± 39), and (412 ± 58) MPa respectively after the application of resin cement.

CONCLUSIONS

Overtime HFA etching could have a wakening effect on IPS e.max® Press glass-ceramic. The application of dual-curing resin cement can compensate the strength loss of the etched glass ceramic.

目的

分析氢氟酸（HFA）蚀刻时间及树脂粘结对IPS e.max® Press玻璃陶瓷抗弯强度的影响，并评估树脂水门汀封闭蚀刻陶瓷裂纹的效果。

方法

采用失蜡热压陶瓷制作技术，用IPS e.max® Press铸锭制作225根棒材（25.0 mm×3.0 mm×2.0 mm），随机分为五组，每组45根。每组中，陶瓷棒表面分别用9.5% HFA凝胶蚀刻0、20、40、60和120秒。每组选取三个样本，用场发射扫描电子显微镜（FE-SEM）观察微观结构。然后将每组随机再分为两个亚组（n = 20）。一个亚组用一层薄（约0.1 mm）的树脂水门汀（Variolink N）覆盖，而另一个亚组保持不变。一半样本在37°C水浴中储存24小时，另一半在进行三点弯曲试验以确定其抗弯强度之前经历10000次热循环。用FE-SEM检查树脂水门汀与蚀刻陶瓷之间的界面。

结果

FE-SEM结果表明，HFA蚀刻导致玻璃陶瓷优先溶解，随着蚀刻时间增加，玻璃基质内部分支撑晶体流失。FE-SEM表明，树脂水门汀封闭了裂纹和缺陷，并与蚀刻陶瓷表面紧密粘结。0、20、40、60和120秒组的平均抗弯强度值分别为（384±33）、（347±43）、（330±53）、（327±67）和（317±41）MPa。除0秒组外，每组在应用树脂水门汀后平均抗弯强度分别显著提高到（420±31）、（435±50）、（400±39）和（412±58）MPa。