Objective

The current laboratory study was to investigate the effect of different sterilization treatments on surface characteristics of zirconia, and biofilm formation on zirconia surface after exposure to these sterilization treatments.

Methods

Commercially available zirconia discs (Cerconbase, Degu-Dent, Hanau, Germany) were prepared and polished to the same value of surface roughness. The discs were treated with one of the following sterilization methods steam autoclave sterilization, dry heat sterilization, ultraviolet C (UVC) irradiation, and gamma (γ) ray irradiation. The characteristics of zirconia surfaces were evaluated by scanning electron microscopy (SEM), surface roughness, surface free energy (SFE), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) measurements. Then, Staphylococcus aureus (S.a.) and Porphyromonas gingivalis (P.g.) bacteria were used and cultured on the respective sterilized zirconia surfaces. The amount of biofilm formation on zirconia surface was quantified by colony forming unit (CFU) counts.

Results

Significant modifications were detected on the colour and SFE of zirconia. The colour of zirconia samples after UVC irradiation became light yellow whilst dark brown colour was observed after gamma ray irradiation. Moreover, UVC and gamma ray irradiation increased the hydrophilicity of zirconia surface. Overall, dry heat sterilized samples showed the significantly lowest amount of bacteria growth on zirconia, while UVC and gamma ray irradiation resulted in the highest.

Significance

It is evident that various sterilization methods could change the surface which contribute to different biofilm formation and colour on zirconia.

中文翻译：

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上表面特性和氧化锆上生物膜形成的不同的灭菌方法的效果的体外

客观的

当前的实验室研究旨在研究不同灭菌处理对氧化锆表面特性的影响，以及暴露于这些灭菌处理后氧化锆表面上生物膜的形成。

方法

制备可商购的氧化锆圆片（Cerconbase，Degu-Dent，德国哈瑙），并抛光至相同的表面粗糙度值。用以下灭菌方法之一对光盘进行处理：蒸汽高压灭菌，干热灭菌，紫外线C（UVC）辐照和伽玛（γ）射线辐照。通过扫描电子显微镜（SEM），表面粗糙度，表面自由能（SFE），X射线光电子能谱（XPS）和X射线衍射（XRD）测量来评估氧化锆表面的特性。然后，金黄色葡萄球菌（Sa）和牙龈卟啉单胞菌（Pg使用细菌并在各自的灭菌氧化锆表面上培养。氧化锆表面上生物膜形成的数量通过菌落形成单位（CFU）计数进行定量。

结果

在氧化锆的颜色和SFE上检测到显着的变化。UVC辐照后氧化锆样品的颜色变为浅黄色，而伽玛射线辐照后观察到深棕色。此外，UVC和伽马射线辐照提高了氧化锆表面的亲水性。总体而言，经干热灭菌的样品显示出氧化锆上细菌的生长量最低，而UVC和伽马射线辐照则最高。

意义

显然，各种灭菌方法可以改变表面，从而导致氧化锆上不同的生物膜形成和颜色。