Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran.
Dent Mater. 2012 Oct;28(10):1041-50. doi: 10.1016/j.dental.2012.06.004. Epub 2012 Jul 12.
Developing a novel dentin bonding system containing poly(methacrylic acid)-grafted-nanoclay (PMAA-g-nanoclay) as reinforcing filler, with high stability of nanoparticle dispersion and improved bond strength and mechanical properties were the main objectives of this study.
Poly(methacrylic acid) (PMAA) was grafted onto the pristine sodium montmorrillonite (Na-MMT) nanoclay surface and characterized using FTIR, TGA, and X-ray diffraction (XRD). The PMAA-g-nanoclay was incorporated into an experimental dentin bonding system as filler in different concentrations and stability of nanoclay dispersion in the dilute adhesive, morphology of nanoclay layers in the photocured adhesive matrix, shear bond strength to caries-free extracted human premolar teeth, and mode of failure were studied. The mechanical properties including diametral tensile strength (DTS), flexural strength (FS), and flexural modulus (FM) were also investigated. The measured FM was also compared to theoretical prediction models.
The grafting of PMAA onto the nanoclay surface was confirmed and the results revealed a partially exfoliated structure for PMAA-g-nanoclay. The dispersion stability of the modified nanoparticles in the dilute adhesive increased more than 45 times in comparison with the pristine nanoclay. The incorporation of 0.5wt.% PMAA-g-nanoclay to the adhesive resulted in a significant increase in microshear bond strength, DTS, and FS. Higher PMAA-g-nanoclay contents resulted in increased flexural modulus. The experimental flexural modulus was in good agreement with the Halpin-Tsai theoretical model.
Incorporation of PMAA-g-nanoclay particles as novel functional fillers into dental adhesive could result in the development of bonding systems with improved physical, mechanical, and adhesion properties.
开发一种新型的牙本质粘结系统，含有聚（甲基丙烯酸）接枝纳米粘土（PMAA-g-纳米粘土）作为增强填料，具有纳米颗粒分散的高稳定性，并提高粘结强度和机械性能，是本研究的主要目标。
在原始的钠蒙脱石（Na-MMT）纳米粘土表面上接枝聚（甲基丙烯酸）（PMAA），并通过傅里叶变换红外光谱（FTIR）、热重分析（TGA）和 X 射线衍射（XRD）进行表征。将 PMAA-g-纳米粘土以不同浓度掺入实验性牙本质粘结系统中作为填料，研究纳米粘土在稀释粘结剂中的分散稳定性、光固化粘结剂基质中纳米粘土层的形态、对无龋人前磨牙的剪切粘结强度和失效模式。还研究了机械性能，包括直径拉伸强度（DTS）、弯曲强度（FS）和弯曲模量（FM）。测量的 FM 也与理论预测模型进行了比较。
证实了 PMAA 接枝到纳米粘土表面上，结果表明 PMAA-g-纳米粘土具有部分剥离结构。与原始纳米粘土相比，改性纳米粒子在稀释粘结剂中的分散稳定性增加了 45 倍以上。将 0.5wt.% PMAA-g-纳米粘土掺入粘结剂中，可显著提高微剪切粘结强度、DTS 和 FS。更高的 PMAA-g-纳米粘土含量导致弯曲模量增加。实验弯曲模量与 Halpin-Tsai 理论模型吻合良好。
将 PMAA-g-纳米粘土颗粒作为新型功能性填料掺入牙科粘结剂中，可开发出具有改善的物理、机械和粘附性能的粘结系统。
