The concentration of saliva is influenced by which environmental factor?

• A. Fluoride in the environment, especially drinking water
• B. pH of blood
• C. Ambient temperature
• D. Time since last meal

Answer: (A)

Environmental fluoride exposure, especially from drinking water, drives the fluoride content in saliva. When fluoride is present in the environment you inhabit, it enters the body and equilibrates with saliva, so higher fluoride levels in water lead to higher salivary fluoride. This is important because saliva with fluoride supports remineralization and helps protect teeth from decay. The other factors aren’t environmental determinants of saliva fluoride concentration: pH of blood reflects systemic acid-base status rather than a driver of how concentrated saliva is; ambient temperature might influence general physiological processes but doesn’t set salivary concentration; and time since the last meal affects flow rate and dilution more than it defines environmental exposure affecting saliva composition.