The present investigation intended to evaluate the bacteriostatic and bactericidal abilities of clove, oregano and thyme essential oils against oral bacteria in planktonic and biofilm states. Furthermore, aiming to mimic everyday conditions, a toothbrush in vitro model was developed. Determination of the minimum inhibitory concentration, minimum bactericidal concentration, minimum biofilm inhibitory concentration and minimum biofilm eradication concentration were achieved using the microdilution procedure. To simulate the toothbrush environment, nylon fibers were inoculated with oral bacteria, which, after incubation to allow biofilm development, were submitted to contact with the essential oils under study. Thyme and oregano essential oils revealed promising antimicrobial effects, both in growth inhibition and the destruction of cells in planktonic and biofilm states, while clove essential oil showed a weaker potential. Regarding the toothbrush in vitro model, observation of the nylon fibers under a magnifying glass proved the essential oil anti-biofilm properties. Considering the effects observed using the in vitro toothbrush model, a realistic approximation to oral biofilm establishment in an everyday use object, a putative application of essential oils as toothbrush sanitizers to help prevent the establishment of bacterial biofilm can be verified.

中文翻译：

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精油对口腔微生物群生物膜的抗菌作用：牙刷体外模型

本研究旨在评估丁香，牛至和百里香精油对浮游生物和生物膜状态的口腔细菌的抑菌和杀菌能力。此外，为了模仿日常状况，开发了牙刷体外模型。使用微稀释程序可以确定最小抑菌浓度，最小杀菌浓度，最小生物膜抑菌浓度和最小生物膜消灭浓度。为了模拟牙刷的环境，在尼龙纤维上接种了口腔细菌，这些细菌经过温育可以使生物膜形成，然后与正在研究的精油接触。百里香和牛至的精油显示出令人鼓舞的抗菌效果，丁香精油显示出较弱的潜力，既抑制生长又抑制浮游生物和生物膜状态下的细胞破坏。关于牙刷的体外模型，在放大镜下观察尼龙纤维证明了精油的抗生物膜特性。考虑到使用体外牙刷模型观察到的效果，对日常使用对象中口腔生物膜的建立有现实的近似，可以验证将精油作为牙刷消毒剂的假定用途，以帮助防止细菌生物膜的建立。