Department of Endodontics, Faculdade de Medicina Dentária, Universidade de Lisboa, Lisboa, Portugal.
Department of Endodontics, Faculdade de Medicina Dentária, Universidade de Lisboa, Lisboa, Portugal.
Dent Mater. 2021 Jul;37(7):e399-e406. doi: 10.1016/j.dental.2021.03.021. Epub 2021 Apr 15.
The water to powder ratio and method of mixing is important for the properties of hydraulic cements. For this purpose a number of clinicians prefer premixed materials. Dental manufacturing companies provide predosed materials, however the manufacturer instructions are not always adhered to. The aim of this research is to investigate physical and chemical alterations of the tricalcium silicate-based cement Biodentine when manipulated according to the manufacturer's instructions (control) or changing the doses and mixing of the material components.
6 groups were constituted according to different mixing and dosing of powder and liquid. The hydrated cements were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Calcium ion concentration of the leachate was also investigated. Assessment of the physical characteristics included setting time and microhardness.
Microstructural differences were visible only in the Biodentine mixed manually with water, in which early hydration rate was also affected, with lower calcium ion release. Increase of Biodentine liquid increased the calcium ion release, but also increased the setting time. Manual manipulation required more liquid (both water and Biodentine liquid) added to the mixture to guarantee a similar consistency to the control. A decrease in setting time was also noted. All groups showed higher values of microhardness at 24 h compared to the freshly set materials. In the freshly set materials, there was an overall decrease in microhardness in all groups when compared to group control, particularly significant when increasing the dosage of Biodentine liquid.
When mixing Biodentine, altering the mixing procedure in terms of type and amount of liquid added to the powder and mixing device chosen has an effect on the physical, chemical and mechanical characteristics and surface topography of the material, when compared to Biodentine mixed according to the manufacturer's recommendations. Hence, the manufacturer's instructions should be strictly followed.
水与粉的比例以及混合方法对水硬水泥的性能非常重要。为此，许多临床医生更喜欢使用预混材料。牙科制造公司提供预混材料，但制造商的说明并不总是被遵守。本研究旨在研究根据制造商的说明（对照）操作或改变材料成分的剂量和混合时，硅酸三钙基水泥 Biodentine 的物理和化学变化。
根据粉末和液体的不同混合和剂量，将 6 组进行分组。采用扫描电子显微镜（SEM）、X 射线衍射（XRD）和傅里叶变换红外光谱（FT-IR）对水化水泥进行了表征。还研究了浸出液中的钙离子浓度。物理特性评估包括凝固时间和显微硬度。
仅在手动用水混合的 Biodentine 中可见微观结构差异，其中早期水化速率也受到影响，钙离子释放减少。增加 Biodentine 液体增加了钙离子释放，但也增加了凝固时间。手动操作需要向混合物中添加更多的液体（水和 Biodentine 液体），以保证与对照品相似的稠度。凝固时间也有所缩短。与刚凝固的材料相比，所有组在 24 小时时均显示出更高的显微硬度值。在刚凝固的材料中，与对照组相比，所有组的显微硬度总体上均降低，尤其是当增加 Biodentine 液体的剂量时，降低更为显著。
在混合 Biodentine 时，改变添加到粉末中的液体的类型和数量以及所选择的混合设备的混合程序，与根据制造商建议混合的 Biodentine 相比，会对材料的物理、化学和机械特性以及表面形貌产生影响。因此，应严格遵守制造商的说明。
