Countermeasures Against COVID-19 from the Viewpoints of Dental Diseases: Strengthening Innate Immunity with the Toothpick Method of Brushing

Coronavirus disease (COVID-19) patients with periodontal disease have an 8.8-fold higher mortality rate than those in the patients without periodontal diseases. This was higher than the odds ratio for patients with diabetes. Periodontal disease is associated with ulcers in the periodontal pocket, and gram-negative bacteria called periodontal pathogens invade the tissue through ulcers. Bacteria in the ulcer site are phagocytosed and sterilized by leukocytes. Following the autolysis of leukocytes, lipopolysaccharides (LPS) on the bacterial cell wall spread throughout the body, which is a major cause of multiple organ failure. Thus, periodontal disease is considered to contribute to the mortality rate of COVID-19. Ulcers in the periodontal pocket can be repaired using by a new developed brushing method called the toothpick method. The toothpick method can significantly improve gingival bleeding in one week, which is quicker than conventional periodontal treatment methods. Mechanical stimulation by the toothbrush causes gingival basal cells, fibroblasts, vascular endothelial cells and osteoblasts to proliferate and repair the tissue. However, these cell proliferations cease to occur 0.5 mm away from where the toothbrush bristles make contact with the gingiva. The toothpick method of brushing is characterized by its ability to stimulate the interdental gingiva, which is the initial site of periodontitis. As the toothpick method can repair periodontal ulcers, it will strengthen biological defense mechanisms against chronic degenerative and infectious diseases.