Effects of Different Ceramic Firing Cycles on cp Titanium-ceramic Under Cyclic Fatigue Loading

• Main Authors: Yi-Pang Lee, 李彞邦
• Other Authors: Chii-Chih Hsu
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/26559297156071514688

碩士 === 中山醫學院 === 牙科材料研究所 === 89 === Titanium is getting more and more interests in dentistry. However, the bonding of ceramic to titanium is still remaining problems. The purpose of this study was to evaluate the flexural bond strength of titanium-ceramic system under different firing cycles (or different bonding agents applying) after cyclic fatigue loading and compare the result of our previous study (Hsu et al., 2000). The fired square-shaped (7mm x7mm) porcelain layer covered an area of central portion of one side of a metal specimen (0.7 x 7 x 20 mm) for a total thickness of 1.0 mm ceramic thickness achieved. In total, 108 specimens were divided into three groups as follows: Group I - applied bonder, opaque and body porcelain; Group II - applied opaque and body porcelain; Group III - applied bonder/opaque mixed and body porcelain. And then each group was divided into three subgroups for different argon supplied: A) no argon supplied; B) argon supplied from 750oC; C) argon supplied from the beginning. All the specimens were submitted to 104 fatigue cycles under 40Kgf at a 10Hz frequency loading. Cross-section of two tested specimen in each subgroup were examined by SEM. After that the rest 10 specimens in each subgroup were subjected to a three-point bending test, and the load of bond failure, called “fracture loads” in this study were recorded. A two-way ANOVA followed by a Tukey posterior multiple comparisons were used to analyze the data. And both optical microscope and SEM with EDS examined the fracture surfaces. The cracking incidence of each subgroup was different between 10% and 60%. The incidences of bubbles in the ceramic layer were different under 3 argon supplied firing schedules. The fracture loads of bonder/opaque mixed together (Group III) did show a statistically significant higher than applied bonder and opaque (Group I) (p<0.05) or no bonder group (Group II) (p<0.05), and there was statistically significant difference among the different argon supplied firing schedules (p=0.048<0.05) but close to the p level (0.05). There were interaction between the different bonders application and different argon supplying. The fracture surfaces analysis showed that the fracture mode was adhesive or mixing type. It was concluded that ceramic bonders or firing times could be the most important factor of the fracture loads of titanium-ceramic under cyclic fatigue loading due to reduce the oxide layer because of less damage under cyclic fatigue loads and incidence of ceramic cracking related to bubbles formation ratio under different argon supplying that could be a factor of the fracture loads.