Hydrogen peroxide, an important antimicrobial agent in oral cavity, plays a significant role in the balance of oral microecology. At the early stage of biofilm formation, about 80% of the detected initial colonizers belong to the genus Streptococcus. These oral streptococci use different oxidase to produce hydrogen peroxide. Recent studies showed that the produced hydrogen peroxide plays a critical role in modulating oral microecology. Hydrogen peroxide modulates biofilm development attributed to its growth inhibitory nature. Hydrogen peroxide production is closely associated with extracellular DNA(eDNA) release from microbe and the development of its competent cell which are critical for biofilm development and also serves as source for horizontal gene transfer. Microbe also can reduce the damage to themselves through several detoxification mechanisms. Moreover, hydrogen peroxide is also involved in the regulation of interactions between oral microorganisms and host. Taken together, hydrogen peroxide is an imperative ecological factor that contributes to the microbial equilibrium in the oral cavity. Here we will give a brief review of both the origin and the function in the oral microecology balance of hydrogen peroxide.
过氧化氢（H₂O₂）作为口腔中一种重要的抑菌物质，在口腔微生态平衡中发挥着重要作用。在口腔龈上菌斑定植的先锋菌中，约有80%细菌属于口腔链球菌属，这些口腔链球菌可以利用不同的氧化酶合成H₂O₂，同时H₂O₂可通过抑制对H₂O₂敏感的微生物参与菌间竞争拮抗，使氧耐受菌得以存活，从而调节生物膜的发展过程；H₂O₂还可通过影响微生物细胞外DNA的释放和感受态细胞的形成进而影响基因的水平转移，调节生物膜对口腔环境的适应能力；同时口腔微生物也可通过一系列机制耐受H₂O₂。此外，H₂O₂在微生物与宿主的关系中也发挥着重要作用。本文就口腔中H₂O₂的来源及其在口腔微生态平衡的作用两方面的研究进展进行综述。.
Keywords: biofilm; hydrogen peroxide; microorganisms and host; oral microbe; oral microecology.