目的:由于口腔内血液和唾液中存在微生物,因此印象材料可能是交叉污染源。然而,常规进行的凝固后消毒可能会损害藻酸盐的尺寸精度和其他机械性能。因此,这项研究旨在评估细节再现,尺寸精度,撕裂强度,和新实验制备的自消毒牙科藻酸盐的弹性恢复。
方法:通过将海藻酸盐粉末与0.2%硝酸银(AgNO3组)和0.2%氯己定溶液(CHX组)代替纯水混合,制备了两个抗菌改性的海藻酸盐牙科组。此外,通过用水提取Boswelliasacra(BS)油树脂来检查第三个改性组。提取物用于还原硝酸银以形成银纳米颗粒(AgNPs),并且该混合物也用于牙科藻酸盐制剂(BS+AgNP组)。根据ISO1563标准指南检查尺寸精度和细节再现。使用刻有三条平行垂直线20、50和75μm宽的金属模具制备样品。通过使用光学显微镜检查50μm线的再现性来评估细节再现。通过测量定义的参考点之间的长度变化来评估尺寸精度。根据ISO1563:1990测量弹性恢复,其中逐渐加载样品,然后释放载荷以允许从变形恢复。使用材料试验机在500mm/min的十字头速度下评价撕裂强度直至失效。
结果:所有测试组之间记录的尺寸变化没有显着差异,并且在报告的可接受值(0.037-0.067mm之间)内。对于撕裂强度,所有测试组之间的差异有统计学意义.与对照组(0.86±0.23N/mm)相比,用CHX(1.17±0.26N/mm)和BS+AgNPs(1.11±0.24N/mm)修饰的组显示更高的撕裂强度值,但与AgNO3(0.94±0.17N/mm)无关。所有测试组均显示出符合ISO标准和ADA规范的弹性印模材料的弹性恢复值,并且撕裂强度值在可接受的记录范围内。
结论:CHX,硝酸银,绿色合成的银纳米粒子可能很有前途,制备自消毒藻酸盐印模材料而不影响其性能的廉价替代品。金属纳米粒子的绿色合成可能是非常安全的,高效,无毒的方法,具有金属离子与植物提取物的活性化学成分之间的协同作用的优点。
OBJECTIVE: Impression materials could be a source of cross-contamination due to the presence of microorganisms from blood and saliva inside the oral cavity. Nevertheless, routinely performed post-setting disinfection could compromise the dimensional accuracy and other mechanical properties of alginates. Thus, this study aimed to evaluate detail reproduction, dimensional accuracy, tear strength, and elastic recovery of new experimentally prepared self-disinfecting dental alginates.
METHODS: Two antimicrobial-modified dental alginate groups were prepared by mixing alginate powder with 0.2% silver nitrate (AgNO3 group) and a 0.2% chlorohexidine solution (CHX group) instead of pure water. Moreover, a third modified group was examined by the extraction of Boswellia sacra (BS) oleoresin using water. The extract was used to reduce silver nitrate to form silver nanoparticles (AgNPs), and the mixture was used as well in dental alginate preparation (BS + AgNP group). Dimensional accuracy and detail reproduction were examined as per the ISO 1563 standard guidelines. Specimens were prepared using a metallic mold engraved with three parallel vertical lines 20, 50, and 75 µm wide. Detail reproduction was evaluated by checking the reproducibility of the 50 µm line using a light microscope. Dimensional accuracy was assessed by measuring the change in length between defined reference points. Elastic recovery was measured according to ISO 1563:1990, in which specimens were gradually loaded and then the load was released to allow for recovery from the deformation. Tear strength was evaluated using a material testing machine until failure at a crosshead speed of 500 mm/min.
RESULTS: The recorded dimensional changes between all tested groups were insignificantly different and within the reported acceptable values (between 0.037-0.067 mm). For tear strength, there were statistically significant differences between all tested groups. Groups modified with CHX (1.17 ± 0.26 N/mm) and BS + AgNPs (1.11 ± 0.24 N/mm) showed higher tear strength values compared to the control (0.86 ± 0.23 N/mm) but were insignificant from AgNO3 (0.94 ± 0.17 N/mm). All tested groups showed elastic recovery values that met both the ISO standard and ADA specifications for elastic impression materials and tear strength values within the acceptable documented ranges.
CONCLUSIONS: The CHX, silver nitrate, and green-synthesized silver nanoparticles could be promising, inexpensive alternatives for the preparation of a self-disinfecting alginate impression material without affecting its performance. Green synthesis of metal nanoparticles could be a very safe, efficient, and nontoxic method, with the advantage of having a synergistic effect between metal ions and active chemical constituents of plant extracts.