全冠牙预备体表面涂布极固宁^(TM)后对其固位力的影响

Effect of Green Or^(TM) on the crown retention using standardized tooth preparation

目的探讨涂布极固宁TM后对全冠固位力的影响。方法制作面聚合度(TOC)为10°和20°的全冠牙预备体各10个,随机分为实验组和对照组。每组TOC10°和20°的全冠牙预备体各5个。制作铸造全冠20个。实验组涂布极固宁TM后玻璃离子黏固剂黏固全冠,对照组直接玻璃离子黏固剂黏固全冠。材料实验机上测两组全冠拉脱时的最大拉力值。扫描电镜观察表面并能谱仪分析。结果TOC为10°的实验组全冠和对照组全冠拉脱时的最大拉力值分别为(443.59±74.20)N和(509.07±69.05)N,两组间的差异无统计学意义(P=0.056);TOC为20°时实验组和对照组全冠拉脱时最大拉力值分别为(291.57±49.27)N和(390.82±91.44)N,两组间的差异有统计学意义(P=0.009)。结论TOC为10°的牙预备体表面经极固宁TM处理后对玻璃离子黏固剂黏固的全冠的固位力没有影响;而TOC为20°时牙预备体表面经极固宁TM处理后的固位力显著下降。

Objective To evaluate the effect of Green OrTM on the crown retention using standardized tooth preparation. Methods Forty recently extracted molars were prepared by lathe. Total oclussal convergence （TOC） angle of half of the molars were 10° and the others were 20°. The cast crowns were made and the samples within each degree were randomly divided into two groups. In the experimental group, Green OrTM was applied to the samples before the cast crown cemented with glass ionomer. In the control group, the samples were only cemented with glass ionomer. The samples were stored in 37 ℃ artificial saliva for 24 h before tensile testing on an instron testing machine at a crosshead speed of 1 mm/min until failure. The surface of the specimen was observed by means of an optical and a scanning electron microscope. Results When TOC angle was 10°, the retention power of the testing force was （443.59±74.20） N of the experimental group and （509.07±69.05） N of the control group respectively. There was no statistically significant difference between the two groups （P=0.056）. When TOC angle was 20°, the retention power of the testing force was （291.57±49.27） N of the experimental group and （390.82±91.44） N of the control group respectively. There was statistically significant difference between two groups （P=0.009）. Conclusion When TOC angle was 10°, there was no effect on the retention power of cast crown luted with glass ionomer after using Green OrTM desensitizer. When TOC angle was 20°, Green Or^TM desensitizer decreased casting retention stress when used with glass ionomer.