Which of the following items are considered antibacterial agents for dental caries?

Xylitol is recognized as an antibacterial agent for dental caries due to its unique biochemical properties. It is a sugar alcohol that possesses the ability to inhibit the growth of Streptococcus mutans, a bacterium that is a major contributor to the formation of dental caries. By replacing sucrose with xylitol in the oral environment, xylitol not only reduces the amount of fermentable carbohydrates available for these bacteria but also alters the bacteria's metabolic processes. This results in decreased acid production, allowing for a more favorable pH balance in the mouth that can help protect against tooth decay.

While fluoride varnish does contain fluoride, which is effective in remineralizing enamel and reducing demineralization, it is distinct from being categorized strictly as an antibacterial agent. Instead, its primary mechanism focuses on enhancing the resistance of teeth to caries rather than directly killing bacteria. Therefore, while beneficial in caries prevention, it does not function in the same manner as xylitol.

Calcium phosphate serves a role in the remineralization of enamel but not as an antibacterial agent. It aids in replacing lost minerals in areas demineralized by acids but does not specifically target or kill bacteria responsible for caries.

Potassium nitrate is primarily