Objectives

A nanoparticle-doped adhesive that can be controlled with magnetic forces was recently developed to deliver drugs to the pulp and improve adhesive penetration into dentin. However, it did not have bactericidal and remineralization abilities. The objectives of this study were to: (1) develop a magnetic nanoparticle-containing adhesive with dimethylaminohexadecyl methacrylate (DMAHDM), amorphous calcium phosphate nanoparticles (NACP) and magnetic nanoparticles (MNP); and (2) investigate the effects on dentin bond strength, calcium (Ca) and phosphate (P) ion release and anti-biofilm properties.

Methods

MNP, DMAHDM and NACP were mixed into Scotchbond SBMP at 2%, 5% and 20% by mass, respectively. Two types of magnetic nanoparticles were used: acrylate-functionalized iron nanoparticles (AINPs); and iron oxide nanoparticles (IONPs). Each type was added into the resin at 1% by mass. Dentin bonding was performed with a magnetic force application for 3 min, provided by a commercial cube-shaped magnet. Dentin shear bond strengths were measured. Streptococcus mutans biofilms were grown on resins, and metabolic activity, lactic acid and colony-forming units (CFU) were determined. Ca and P ion concentrations in, and pH of biofilm culture medium were measured.

Results

Magnetic nanoparticle-containing adhesive using magnetic force increased the dentin shear bond strength by 59% over SBMP Control (p < 0.05). Adding DMAHDM and NACP did not adversely affect the dentin bond strength (p > 0.05). The adhesive with MNP + DMAHDM + NACP reduced the S. mutans biofilm CFU by 4 logs. For the adhesive with NACP, the biofilm medium became a Ca and P ion reservoir. The biofilm culture medium of the magnetic nanoparticle-containing adhesive with NACP had a safe pH of 6.9, while the biofilm medium of commercial adhesive had a cariogenic pH of 4.5.

Significance

Magnetic nanoparticle-containing adhesive with DMAHDM and NACP under a magnetic force yielded much greater dentin bond strength than commercial control. The novel adhesive reduced biofilm CFU by 4 logs and increased the biofilm pH from a cariogenic pH 4.5–6.9, and therefore is promising to enhance the resin–tooth bond, strengthen tooth structures, and suppress secondary caries at the restoration margins.

中文翻译：

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具有更大的牙本质粘合强度以及抗菌和矿化能力的新型含磁性纳米颗粒的粘合剂

目标

最近开发了一种可以用磁力控制的掺杂纳米颗粒的胶粘剂，以将药物输送到纸浆中，并提高胶粘剂渗透到牙本质中的渗透率。但是，它不具有杀菌和再矿化的能力。这项研究的目的是：（1）用甲基丙烯酸二甲氨基十六烷基酯（DMAHDM），无定形磷酸钙纳米颗粒（NACP）和磁性纳米颗粒（MNP）开发含磁性纳米颗粒的粘合剂；（2）研究对牙本质键强度，钙（Ca）和磷酸盐（P）离子释放以及抗生物膜特性的影响。

方法

将MNP，DMAHDM和NACP分别以2质量％，5％质量和20质量％混合到Scotchbond SBMP中。使用了两种类型的磁性纳米粒子：丙烯酸酯官能化的铁纳米粒子（AINP）；以及 和氧化铁纳米粒子（IONPs）。将每种类型以1质量％添加到树脂中。牙本质粘合是在市售立方磁体提供的磁力作用下进行的3分钟。测量了牙本质剪切粘合强度。变形链球菌生物膜在树脂上生长，并测定代谢活性，乳酸和菌落形成单位（CFU）。测量了生物膜培养基中Ca和P离子的浓度以及pH。

结果

与SBMP对照相比，使用磁力的含磁性纳米颗粒的粘合剂将牙本质剪切粘合强度提高了59％（p <  0.05）。添加DMAHDM和NACP不会对牙本质粘合强度产生不利影响（p  > 0.05）。带有MNP + DMAHDM + NACP的胶粘剂使变形链球菌生物膜CFU降低了4个对数。对于具有NACP的粘合剂，生物膜介质成为Ca和P离子的储库。具有NACP的含磁性纳米颗粒的粘合剂的生物膜培养基的安全pH为6.9，而市售粘合剂的生物膜培养基的生龋pH为4.5。

意义

在磁力的作用下，具有DMAHDM和NACP的含磁性纳米粒子的粘合剂产生的牙本质粘合强度比商业对照大得多。新型粘合剂将生物膜的CFU降低了4个对数，并将生物膜的pH从生龋的pH值4.5-6.9提高了，因此有望增强树脂-牙齿的结合力，增强牙齿的结构，并在恢复边缘抑制继发性龋齿。