Nanobacteria are the smallest known bacteria, and the adamant shells they form have relations with pathologic calcification. About its “living organism”, a great deal of controversy has raised within the scientific community in recent years. There have been evidences that abundance of nanobacteria in the oral cavity such as saliva, the surface of the teeth, dental plaque, calculus dentalis, pulp stone and so on. This article reviews nanobacteria and its role in oral disease and other systemic disease.
