Progress in application of metagenomics in studying common oral cavity chronic infectious diseases

The common chronic infectious diseases in oral cavity mainly include caries, pulp disease, periapical disease, periodontal disease, wisdom tooth pericoronitis and jaw osteomyelitis, etc. They are usually related to pathogenic bacteria, and the research on the etiology of these disease also focuses on the discovery of disease-related pathogenic bacteria. Due to the limitation of traditional culture technique, researchers had no comprehensive understanding of microorganisms, and believed that oral chronic infectious diseases were caused by a specific pathogenic microorganism. With the emergence and development of metagenomics and its sequencing technique, a large number of oral microorganisms has been discovered, which has broken the limitation of human knowledge and resulted in subsequent founding of oral microbial flora composition and change under different environment, healthy and pathogenic microorganism species, or special species in the disease development process and provided powerful evidence for the prevention and treatment of chronic oral cavity infectious diseases. In this article, we summarize the metagenomics technique and the progress in application of this technique in studying several common chronic oral cavity infectious diseases.