Oral Technology, Medical Faculty, University Hospital Bonn, Bonn, Germany.
Department of Orthodontics, Medical Faculty, University Hospital Bonn, Bonn, Germany.
Clin Oral Investig. 2023 Nov;27(11):6677-6688. doi: 10.1007/s00784-023-05277-8. Epub 2023 Sep 30.
Disinfection of alginate impression materials is a mandatory step to prevent cross-infection in dental clinics. However, alginate disinfection methods are time-consuming and exert a negative impact on accuracy and mechanical properties. Thus, this study aimed to prepare disinfecting agents (CHX and AgNO) and silver nanoparticles reduced by a natural plant extract to produce a self-disinfecting dental alginate.
Conventional alginate impression material was used in this study. Silver nitrate (0.2% AgNO group) and chlorohexidine (0.2% CHX group) solutions were prepared using distilled water, and these solutions were later employed for alginate preparation. Moreover, a 90% aqueous plant extract was prepared from Boswellia sacra (BS) oleoresin and used to reduce silver nitrate to form silver nanoparticles that were incorporated in the dental alginate preparation (BS+AgNPs group). The plant extract was characterized by gas chromatography/mass spectrometry (GC/MS) analysis while green-synthesized silver nanoparticles (AgNPs) were characterized by UV-visible (UV-vis) spectroscopy and scanning electron microscopy (SEM). An agar disc diffusion assay was used to test the antimicrobial activity against Candida albicans, Streptococcus mutans, Escherichia coli, methicillin-resistant and susceptible Staphylococcus aureus strains, and Micrococcus luteus. Agar plates were incubated at 37 ± 1 °C for 24 h to allow microbial growth. Diameters of the circular inhibition zones formed around each specimen were measured digitally by using ImageJ software.
Chemical analysis of the plant extract revealed the presence of 41 volatile and semi-volatile active compounds. UV-Vis spectrophotometry, SEM, and EDX confirmed the formation of spherical silver nanoparticles using the BS extract. CHX, AgNO, and the BS+AgNPs modified groups showed significantly larger inhibition zones than the control group against all tested strains. BS+AgNPs and CHX groups showed comparable efficacy against all tested strains except for Staphylococcus aureus, where the CHX-modified alginate had a significantly higher effect.
CHX, silver nitrate, and biosynthesized silver nanoparticles could be promising inexpensive potential candidates for the preparation of a self-disinfecting alginate impression material without affecting its performance. Green synthesis of metal nanoparticles using Boswellia sacra extract could be a very safe, efficient, and nontoxic way with the additional advantage of a synergistic action between metal ions and the phytotherapeutic agents of the plant extract.
为了防止牙科诊所发生交叉感染，对藻酸盐印模材料进行消毒是一项强制性步骤。然而，藻酸盐的消毒方法既耗时又会对准确性和机械性能产生负面影响。因此，本研究旨在制备消毒剂（洗必泰和硝酸银）和由天然植物提取物还原的银纳米粒子，以生产自消毒牙科藻酸盐。
本研究使用常规的藻酸盐印模材料。使用蒸馏水制备硝酸银（0.2%AgNO 组）和洗必泰（0.2%CHX 组）溶液，并将这些溶液用于藻酸盐的制备。此外，从乳香（Boswellia sacra）香树脂中制备 90%的水性植物提取物，并将其用于还原硝酸银以形成银纳米粒子，将其掺入牙科藻酸盐制备中（BS+AgNPs 组）。通过气相色谱/质谱（GC/MS）分析对植物提取物进行了表征，通过紫外可见（UV-vis）光谱和扫描电子显微镜（SEM）对绿色合成的银纳米粒子（AgNPs）进行了表征。琼脂圆盘扩散法用于测试抗白色念珠菌、变异链球菌、大肠杆菌、耐甲氧西林和敏感金黄色葡萄球菌以及藤黄微球菌的抗菌活性。将琼脂平板在 37±1°C 下孵育 24 小时，以允许微生物生长。使用 ImageJ 软件数字化测量每个标本周围形成的圆形抑制区的直径。
植物提取物的化学分析表明存在 41 种挥发性和半挥发性活性化合物。紫外可见分光光度法、SEM 和 EDX 证实了使用 BS 提取物形成了球形银纳米粒子。CHX、AgNO 和 BS+AgNPs 改性组对所有测试菌株的抑制区明显大于对照组。BS+AgNPs 和 CHX 组对所有测试菌株的效果相当，除了金黄色葡萄球菌，其中 CHX 改性藻酸盐的效果明显更高。
洗必泰、硝酸银和生物合成的银纳米粒子可能是一种有前途的廉价潜在候选物，可用于制备性能不受影响的自消毒藻酸盐印模材料。使用乳香提取物进行金属纳米粒子的绿色合成可能是一种非常安全、高效和无毒的方法，具有金属离子与植物提取物的植物治疗剂之间协同作用的额外优势。
