Development of Intracanal Formulation Containing Silver Nanoparticles

This study aimed to synthetize, characterize and evaluate the antimicrobial properties of silver nanoparticles to be used in the development of a root intracanal formulation. Silver nanoparticles (AgNPs) were obtained by reduction of silver nitrate with sodium borohydride and characterized by UV-Visible spectrophotometry, scanning electron microscopy (SEM) and dynamic light scattering (DLS). The antimicrobial activity of nanoparticle formulation was evaluated by determinations of the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against different bacterial species by the microdilution method, according to recommendations of the Clinical and Laboratory Standards Institute (CLSI). Three potential vehicles, hydroxyethylcellulose, Carbomer and polyethylene glycol were tested as carriers for formulations containing AgNPs. The efficiency of the synthesis method chosen to produce AgNPs was demonstrated by four characterization techniques. The nanoparticles showed antibacterial activity against all species tested. Incorporation of AgNPs into all experimental vehicles produced stable formulations but the one in hydroxyethylcellulose presented better physical proprieties. The results indicate that silver nanoparticles are potential antiseptic agents to be used in root canals and incorporation in adequate vehicles may favor a broader application.本研究旨在合成、表征并评估银纳米颗粒的抗菌性能，以用于根管内制剂的开发。银纳米颗粒（AgNPs）通过硼氢化钠还原硝酸银制备得到，并采用紫外-可见分光光度法、扫描电子显微镜（scanning electron microscopy, SEM）与动态光散射（dynamic light scattering, DLS）进行表征。参照临床与实验室标准化协会（Clinical and Laboratory Standards Institute, CLSI）的建议，本研究采用微量稀释法，通过测定最小抑菌浓度（minimum inhibitory concentration, MIC）与最小杀菌浓度（minimum bactericidal concentration, MBC），评估该纳米颗粒制剂对不同受试菌种的抗菌活性。本研究选取羟乙基纤维素、卡波姆与聚乙二醇三种潜在载体，用于负载含AgNPs的制剂并开展测试。所选AgNPs合成方法的有效性，通过四种表征技术得到了验证。该纳米颗粒对所有受试菌种均表现出抗菌活性。将AgNPs掺入所有实验载体中均可获得稳定制剂，但以羟乙基纤维素为载体的制剂展现出更优异的物理性能。研究结果表明，银纳米颗粒是可用于根管治疗的潜在防腐制剂，掺入合适的载体可助力其应用范围的进一步拓展。