Maletin Aleksandra, Ristić Ivan, Nešić Aleksandra, Knežević Milica Jeremić, Koprivica Daniela Đurović, Cakić Suzana, Ilić Dušica, Milekić Bojana, Puškar Tatjana, Pilić Branka
Faculty of Medicine, University of Novi Sad, 21000 Novi Sad, Serbia.
Faculty of Technology, University of Novi Sad, 21000 Novi Sad, Serbia.
Polymers (Basel). 2023 Jun 7;15(12):2598. doi: 10.3390/polym15122598.
As the mechanical properties of resin-based dental composite materials are highly relevant in clinical practice, diverse strategies for their potential enhancement have been proposed in the extant literature, aiming to facilitate their reliable use in dental medicine. In this context, the focus is primarily given to the mechanical properties with the greatest influence on clinical success, i.e., the longevity of the filling in the patient's mouth and its ability to withstand very strong masticatory forces. Guided by these objectives, the goal of the present study was to ascertain whether the reinforcement of dental composite resins with electrospun polyamide (PA) nanofibers would improve the mechanical strength of dental restoration materials. For this purpose, light-cure dental composite resins were interspersed with one and two layers comprising PA nanofibers in order to investigate the influence of such reinforcement on the mechanical properties of the resulting hybrid resins. One set of the obtained samples was investigated as prepared, while another set was immersed in artificial saliva for 14 days and was subsequently subjected to the same set of analyses, namely Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Findings yielded by the FTIR analysis confirmed the structure of the produced dental composite resin material. They also provided evidence that, while the presence of PA nanofibers did not influence the curing process, it strengthened the dental composite resin. Moreover, flexural strength measurements revealed that the inclusion of a 16 μm-thick PA nanolayer enabled the dental composite resin to withstand a load of 3.2 MPa. These findings were supported by the SEM results, which further indicated that immersing the resin in saline solution resulted in a more compact composite material structure. Finally, DSC results indicated that as-prepared as well as saline-treated reinforced samples had a lower glass transition temperature (Tg) compared to pure resin. Specifically, while pure resin had a Tg of 61.6 °C, each additional PA nanolayer decreased the Tg by about 2 °C, while the further reduction was obtained when samples were immersed in saline for 14 days. These results show that electrospinning is a facile method for producing different nanofibers that can be incorporated into resin-based dental composite materials to modify their mechanical properties. Moreover, while their inclusion strengthens the resin-based dental composite materials, it does not affect the course and outcome of the polymerization reaction, which is an important factor for their use in clinical practice.
由于树脂基牙科复合材料的机械性能在临床实践中具有高度相关性，现有文献中提出了多种增强其性能的策略，旨在促进其在牙科医学中的可靠应用。在此背景下，重点主要放在对临床成功影响最大的机械性能上，即填充物在患者口腔中的使用寿命及其承受非常强大咀嚼力的能力。以这些目标为导向，本研究的目的是确定用静电纺聚酰胺（PA）纳米纤维增强牙科复合树脂是否会提高牙科修复材料的机械强度。为此，将光固化牙科复合树脂与包含PA纳米纤维的一层和两层进行穿插，以研究这种增强对所得混合树脂机械性能的影响。一组获得的样品按制备状态进行研究，而另一组样品在人工唾液中浸泡14天，随后进行相同的一组分析，即傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和差示扫描量热法（DSC）。FTIR分析得出的结果证实了所制备的牙科复合树脂材料的结构。这些结果还表明，虽然PA纳米纤维的存在不影响固化过程，但它增强了牙科复合树脂。此外，弯曲强度测量表明，包含16μm厚的PA纳米层使牙科复合树脂能够承受3.2MPa的载荷。SEM结果支持了这些发现，进一步表明将树脂浸泡在盐溶液中会导致复合材料结构更致密。最后，DSC结果表明，与纯树脂相比，制备好的以及经过盐水处理的增强样品具有更低的玻璃化转变温度（Tg）。具体而言，虽然纯树脂的Tg为61.6℃，每增加一层PA纳米层，Tg会降低约2℃，而当样品在盐水中浸泡14天时会进一步降低。这些结果表明，静电纺丝是一种制备不同纳米纤维的简便方法，这些纳米纤维可掺入树脂基牙科复合材料中以改变其机械性能。此外，虽然它们的加入增强了树脂基牙科复合材料，但不影响聚合反应的过程和结果，这是它们在临床实践中使用的一个重要因素。
