Vechiato Filho Aljomar José, dos Santos Daniela Micheline, Goiato Marcelo Coelho, de Medeiros Rodrigo Antonio, Moreno Amália, Bonatto Liliane da Rocha, Rangel Elidiane Cipriano
Graduate student, Graduate Program in Dentistry, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil.
Professor, Department of Dental Materials and Prosthodontics, Araçatuba Dental School, São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil.
J Prosthet Dent. 2014 Nov;112(5):1156-63. doi: 10.1016/j.prosdent.2014.02.021. Epub 2014 Jun 11.
Surface transformation with nonthermal plasma may be a suitable treatment for dental ceramics, because it does not affect the physical properties of the ceramic material.
The purpose of this study was to characterize the chemical composition of lithium disilicate ceramic and evaluate the surface of this material after nonthermal plasma treatment.
A total of 21 specimens of lithium disilicate (10 mm in diameter and 3 mm thick) were fabricated and randomly divided into 3 groups (n=7) according to surface treatment. The control group was not subjected to any treatment except surface polishing with abrasive paper. In the hydrofluoric acid group, the specimens were subjected to hydrofluoric acid gel before silane application. Specimens in the nonthermal plasma group were subjected to the nonthermal plasma treatment. The contact angle was measured to calculate surface energy. In addition, superficial roughness was measured and was examined with scanning electron microscopy, and the chemical composition was characterized with energy-dispersive spectroscopy analysis. The results were analyzed with ANOVA and the Tukey honestly significant difference test (α=.05).
The water contact angle was decreased to 0 degrees after nonthermal plasma treatment. No significant difference in surface roughness was observed between the control and nonthermal plasma groups. Scanning electron microscopy and energy-dispersive spectroscopy images indicated higher amounts of oxygen (O) and silicon (Si) and a considerable reduction in carbon (C) in the specimens after nonthermal plasma treatment.
Nonthermal plasma treatment can transform the characteristics of a ceramic surface without affecting its surface roughness. A reduction in C levels and an increase in O and Si levels were observed with the energy-dispersive spectroscopy analysis, indicating that the deposition of the thin silica film was efficient.
非热等离子体表面处理可能是牙科陶瓷的一种合适处理方法，因为它不会影响陶瓷材料的物理性能。
本研究的目的是表征二硅酸锂陶瓷的化学成分，并评估非热等离子体处理后该材料的表面。
共制作21个二硅酸锂试样（直径10mm，厚3mm），并根据表面处理方法随机分为3组（n = 7）。对照组除用砂纸进行表面抛光外未进行任何处理。在氢氟酸组中，试样在应用硅烷之前进行氢氟酸凝胶处理。非热等离子体组的试样进行非热等离子体处理。测量接触角以计算表面能。此外，测量表面粗糙度并用扫描电子显微镜进行检查，并用能谱分析表征化学成分。结果采用方差分析和Tukey真实显著性差异检验（α = 0.05）进行分析。
非热等离子体处理后水接触角降至0度。对照组和非热等离子体组之间在表面粗糙度上未观察到显著差异。扫描电子显微镜和能谱图像表明，非热等离子体处理后的试样中氧（O）和硅（Si）含量较高，碳（C）含量显著降低。
非热等离子体处理可改变陶瓷表面特性而不影响其表面粗糙度。能谱分析观察到C含量降低，O和Si含量增加，表明二氧化硅薄膜的沉积是有效的。
