Associate Professor, Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirao Preto, University of Sao Paulo (USP), Ribeirao Preto, Brazil.
Associate Professor, School of Dentistry of University Federal of Sergipe, Aracaju, Brazil.
J Prosthet Dent. 2021 Dec;126(6):804.e1-804.e9. doi: 10.1016/j.prosdent.2021.08.013. Epub 2021 Oct 13.
Oxidation heat treatment has been studied to increase the metal-ceramic bond strength. However, information about its use with cobalt-chromium (Co-Cr) alloys is lacking.
The purpose of this study was to evaluate the effect of oxidation heat treatment and oxidation heat treatment with alumina airborne-particle abrasion on the metal-ceramic bond strength of Co-Cr alloys compared with that of nickel-chromium (Ni-Cr) alloys.
In total, 165 metal cylinders (∅5×8 mm) made of 5 base metal alloys were obtained by casting: 2 Ni-Cr (Fit Cast-SB and Fit Cast-V) and 3 Co-Cr alloys (Keragen, StarLoy C, and Remanium 2001). The specimens were divided into groups (n=11): no treatment, oxidation heat treatment, and oxidation heat treatment with airborne-particle abrasion. Oxidation heat treatment was performed starting at 650 °C and rising to 980 °C. The airborne-particle abrasion was performed with 100-μm alumina (0.2-MPa pressure, 5 seconds). One specimen had the surface topography and composition evaluated by scanning electron microscopy and energy dispersive X-ray spectrometry. The feldspathic ceramic was applied to the base metal alloy specimens (n=10). Shear tests were performed to obtain the metal-ceramic bond strength (MPa). The failure modes were evaluated. Data were evaluated by 2-way ANOVA and the Tukey post hoc test, Pearson correlation, and Fisher exact tests (α=.05).
The group without treatment showed the highest roughness. The treatments increased oxygen and chromium levels and decreased nickel, molybdenum, and tungsten levels. Oxidation heat treatment provided an increase in metal-ceramic bond strength (P<.05) for base metal alloys with over 7% molybdenum (Fit Cast-SB, Fit Cast-V, and Remanium 2001). With oxidation heat treatment with airborne-particle abrasion, there was improvement only in Fit Cast-SB. No treatment was better for StarLoy C. A weak correlation was found between metal-ceramic bond strength and failure mode (ρ=.166; P=.043). The mixed failures were prevalent in Co-Cr alloys (P<.001) and oxidation heat treatment with airborne-particle abrasion (P=.008).
The oxidation heat treatment was only beneficial for base metal alloy with a molybdenum content of over 7%. Although the oxidation heat treatment with alumina airborne-particle abrasion was a better treatment for Fit Cast-SB, its use is not justified because it showed no difference for oxidation heat treatment and requires another step in the surface treatment.
氧化热处理已被研究用于提高金属-陶瓷结合强度。然而，关于其在钴铬（Co-Cr）合金中的应用的信息尚缺乏。
本研究的目的是评估氧化热处理和氧化热处理联合氧化铝喷丸对 Co-Cr 合金与镍铬（Ni-Cr）合金的金属-陶瓷结合强度的影响。
通过铸造获得 165 个金属圆柱体（∅5×8mm），由 5 种基底金属合金组成：2 种 Ni-Cr（Fit Cast-SB 和 Fit Cast-V）和 3 种 Co-Cr 合金（Keragen、StarLoy C 和 Remanium 2001）。将样品分为以下几组（n=11）：无处理、氧化热处理和氧化热处理联合氧化铝喷丸。氧化热处理从 650°C 开始升温至 980°C。氧化铝喷丸采用 100-μm 氧化铝进行（0.2-MPa 压力，5 秒）。对一个样品的表面形貌和组成进行扫描电子显微镜和能量色散 X 射线光谱分析。将长石质陶瓷应用于基底金属合金样品（n=10）。进行剪切试验以获得金属-陶瓷结合强度（MPa）。评估失效模式。采用双向方差分析和 Tukey 事后检验、Pearson 相关和 Fisher 确切概率检验（α=.05）进行数据评估。
未经处理的组显示出最高的粗糙度。处理增加了氧和铬的含量，降低了镍、钼和钨的含量。氧化热处理提高了钼含量超过 7%的基底金属合金的金属-陶瓷结合强度（P<.05）（Fit Cast-SB、Fit Cast-V 和 Remanium 2001）。氧化热处理联合氧化铝喷丸处理仅对 Fit Cast-SB 有效。StarLoy C 则更适合未经处理。金属-陶瓷结合强度与失效模式之间存在弱相关（ρ=.166；P=.043）。混合失效在 Co-Cr 合金中更为常见（P<.001），氧化热处理联合氧化铝喷丸处理也是如此（P=.008）。
氧化热处理仅对钼含量超过 7%的基底金属合金有益。尽管氧化热处理联合氧化铝喷丸处理对 Fit Cast-SB 是更好的处理方法，但由于其对氧化热处理没有差异，且需要增加表面处理的另一步骤，因此其使用并不合理。
