This study aimed to demonstrate subgingival microbial changes associated with development, prevention, and treatment of experimental gingivitis using chlorhexidine (CHX) and N-acetylcysteine (NAC) mouthwashes. This randomized clinical trial comprised two parts: a 3-week prevention sub-study in which 30 study subjects were equally assigned to either mouthwash or placebo while developing experimental gingivitis; followed by a 2-week treatment sub-study in which 20 subjects with experimental gingivitis were assigned to either mouthwash. Subgingival samples were collected at the beginning and end of each sub-study for microbial profiling with 16S rRNA gene sequencing. As expected, CHX was effective in both preventing and reversing experimental gingivitis; NAC had a modest effect. Gingivitis was associated with enrichment of TM7 HOT-346/349, Tannerella HOT-286, Cardiobacterium valvarum, Campylobacter gracilis, Porphyromonas catoniae, Leptotrichia HOT-219, and Selenomonas spp. At the phylum/genus level, TM7 showed the strongest association. Gingival health was associated with increased abundance of Haemophilus parainfluenzae, Lautropia mirabilis, Rothia spp., Streptococcus spp., and Kingella oralis. CHX demonstrated largely indiscriminate antimicrobial action, resulting in significant drop in biomass and diversity. Our results substantiate the role of specific oral bacterial species in the development of gingivitis. They also indicate that NAC is not a promising mouthwash at the concentration tested.

这项研究旨在证明使用洗必泰（CHX）和N-乙酰半胱氨酸（NAC）漱口水与实验性牙龈炎的发生，预防和治疗相关的龈下微生物变化。这项随机临床试验包括两个部分：为期3周的预防性子研究，其中30名研究对象在发展为实验性牙龈炎时被平均分配为漱口水或安慰剂。随后进行为期2周的治疗子研究，其中20名患有实验性牙龈炎的受试者被分配为漱口水。在每个子研究的开始和结束时收集龈下样品，以进行16S rRNA的微生物分析基因测序。正如预期的那样，CHX可以有效预防和逆转实验性牙龈炎。NAC的影响不大。牙龈炎与TM7 HOT-346 / 349，坦氏杆菌HOT-286，瓦尔氏杆菌，弯曲杆菌，卡氏卟啉单胞菌，细杆菌HOT-219和Selen o monas spp的富集有关。在门/属水平上，TM7显示最强的关联。牙龈健康与副流感嗜血杆菌，奇异的Lauttropia，Rothia spp。，Streptococcus spp。和Kingella Oralis的丰度增加有关。CHX在很大程度上表现出不加区分的抗菌作用，导致生物量和多样性显着下降。我们的结果证实了特定口腔细菌物种在牙龈炎发展中的作用。他们还表明，在所测试的浓度下，NAC并非有希望的漱口水。