玻璃离子水门汀加入二氧化钛纳米颗粒后的机械与抑菌性能

摘要

BACKGROUND:Glass ionomer cements have been gradual y employed in many aspects of dental clinical field. However, low mechanical strength and antibacterial effect restrict its further applications. OBJECTIVE:To proportional y explore the effects of titanium dioxide nanoparticles on the mechanical strength and antibacterial effect of traditional glass ionomer cements. METHODS:Base on different mass fractions of titanium dioxide nanoparticles in glass ionomer cements, al the glass ionomer cement samples were divided into control group (no titanium dioxide nanoparticles), low titanium dioxide group (containing 3%titanium dioxide nanoparticles), medium titanium dioxide group (containing 6%titanium dioxide nanoparticles), and high titanium dioxide group (containing 9%titanium dioxide nanoparticles). A universal material testing machine and a hardness tester were used to examine flexural strength, compressive strength, and surface hardness of glass ionomer cement samples, respectively. Glass ionomer cement samples were immerged into the artificial saliva, and fluoride release was measured by using a fluoride ion selective electrode. The direct contact test was used to investigate antibacterial effect of glass ionomer cement samples towards Streptococcus mutans. RESULTS AND CONCLUSION:Compared with the control group, few titanium dioxide nanoparticles (low and medium titanium dioxide group) could significantly improve flexural strength, compressive strength and surface hardness of glass ionomer cement samples (P<0.05), and high titanium dioxide nanoparticles (high titanium dioxide group) significantly decreased flexural strength, compressive strength and surface hardness (P<0.05). The introduction of titanium dioxide nanoparticles had little effect on fluorine release behavior of glass ionomer cement samples, and greatly improved antibacterial effect of glass ionomer cement samples towards Streptococcus mutans.%背景：玻璃离子水门汀已被逐渐应用于口腔临床的诸多方面，但其机械强度较低、抑菌作用不明显，限制了其进一步广泛应用。目的：考察加入不同比例二氧化钛纳米颗粒对玻璃离子水门汀机械性能和抑菌作用的提升效果。方法：实验分4组，低、中、高质量分数二氧化钛组玻璃离子水门汀中分别含3%，6%，9%二氧化钛纳米颗粒，对照组不含二氧化钛纳米颗粒。利用万能材料试验机和硬度测试仪考察各组试件的抗弯强度、抗压强度和表面硬度。将试样浸没在人工唾液中，采用氟离子选择性电极测定氟释放量累积量，利用直接接触法考察试样对变形链球菌的抑菌效果。结果与结论：与对照组相比，低、中质量分数二氧化钛组高玻璃离子水门汀的抗弯强度、抗压强度和表面硬度显著提高(P <0.05)，高质量分数二氧化钛组显著下降(P <0.05)。各组玻璃离子水门汀的氟释放累积量随时间变化均表现为平滑递增曲线。低质量分数二氧化钛组变形链球菌的吸光度值最低。说明二氧化钛纳米颗粒的加入对玻璃离子水门汀的氟释放行为影响不显著，可显著提高对变形链球菌的抑菌效果。