The effect of different types of atmosphere on the bond strength of low-fusing porcelain bonded to pure titanium

• Main Authors: Chen-Shih Liu, 劉承世
• Other Authors: Chun-Cheng Hung
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/74684964782091441174

碩士 === 高雄醫學大學 === 牙醫學研究所 === 96 === Statement of problem：Due to the pronounced oxidative nature of titanium at high temperatures, an excessively thick layer of TiO2 may form on the surface. This oxide layer could adversely affect titanium-porcelain bonding. Purpose：An in vitro investigation was performed to evaluate the bonding characteristics of c.p.Ti in various firing atmospheres. Material and methods：This study evaluated the bonding strength of commercial titanium porcelains fired in a vacuum, argon and helium atmosphere. According to DIN13927, 3-point bending test has been used. Three groups of ASTM grade 2 commercially pure titanium（25mm × 3mm × 0.5mm）were prepared（n=15）. All titanium specimens were abraded with 110μm Alumina particles. An ultra low-fusing porcelain（Vita Titankeramik）was fused on the central area of titanium specimen（8mm × 3mm × 1mm）. Porcelain was fired under vacuum, argon and helium, then debonded by a universal testing machine at a cross-head speed of 0.5 mm/min. Interface cross-sections of the titanium-porcelain were examined in a scanning electron microscope（SEM）with energy dispersive spectrometry analysis（EDS）. X-ray diffraction analysis（XRD）and microhardness were also evaluated. Results were analyzed by one-way ANOVA/Tukey-Kramer HSD test (p＜0.05). Results：Statistical analysis showed a significant difference in the microhardness among all groups. Microhardness of the group fired in helium was significant lower than groups fired in vacuum and argon（P＜0.05）, and no significant different between helium group and original titanium group. Bond strength value of argon group is significantly higher than that of vacuum group and helium group（P＜0.05）.SEM and EDS revealed that porcelain remnant of helium group is the most among three groups. XRD showed that the intensity of TiO2 is more eminent in argon and vacuum group. conclusion： Firing porcelain in an argon atmosphere showed the better bond strength between titanium and porcelain than fired in a vacuum or helium atmosphere. Porcelain fired in a helium atmosphere revealed prominent bubbles and defects. Therefore, something must be done to improve the properties of porcelain during firing in a helium atmosphere to achieve clinical requirement. Keywords：Argon, Vacuum, Bond strength, Porcelain, Titanium