But there are not only harmful bacteria in the oral cavity, but millions of microorganisms parasites, including harmful bacteria, neutral bacteria and beneficial bacteria, which maintain the relative balance of oral flora, thereby maintaining oral health. When harmful bacteria multiply, they can cause tooth decay, gingivitis, and bad breath. For example, Streptococcus mutans is the chief culprit of dental plaque, and dental plaque is a necessary factor for dental caries and periodontitis. It can be said that without dental plaque, there will be no dental caries and periodontitis. 80 percent of bad breath is due to the excessive reproduction of oral anaerobic bacteria, which decompose and digest food residues, organic matter and blood in the oral cavity to produce volatile sulfides. Fortunately, probiotics are able to restore the balance of oral flora to maintain oral health.

Probiotics are a class of active microorganisms that are beneficial to the host. They are a general term for active beneficial microorganisms that colonize the human intestinal tract and reproductive system and can produce definite health effects, thereby improving the host's micro-ecological balance and playing a beneficial role.

Dental probiotics can be beneficial in several ways, such as: increased resistance to infection through antimicrobial activity (production of organic acids, hydrogen peroxide and bacteriocins), formation of biofilms to protect oral tissues from Competitive adhesion of pathogenic bacteria to the tooth surface, adjustment of pH and redox potential, enhancement of the host's cellular and humoral immune systems, etc. In addition, probiotic fermentation can produce vitamins B6 and B12, riboflavin, folic acid, niacin, short-chain fatty acids and other substances, which can help improve gastrointestinal function and even halitosis disorders.

Dental probiotics have various advantages, such as antibacterial activity, strong binding ability, formation of protective biofilm, regulation of pH and redox potential, enhancement of immune system, reduction of production of pro-inflammatory cytokines, etc., which can help improve oral diseases, Thereby preventing or improving oral halitosis. Probiotics have the potential to help us keep our breath fresh.