What fluoride concentration in drinking water is likely to cause pitting in people's teeth?

• A. 2 mg/L
• B. 3 mg/L
• C. 4 mg/L
• D. 5 mg/L

Answer: (C)

The fluoride concentration in drinking water that is likely to cause dental pitting, also known as dental fluorosis, typically occurs at higher levels. While fluoride is beneficial for dental health in small amounts, excessive exposure, especially during the years when teeth are developing, can lead to cosmetic issues such as pitting and discoloration.

A fluoride concentration of 4 mg/L is generally recognized as a threshold level where the risk of dental fluorosis, including the development of pitting, significantly increases. At this concentration, not only can the aesthetics of the teeth be affected, but the integrity of the enamel may also be compromised. This is especially critical for children, as their teeth are still developing and are more susceptible to the effects of elevated fluoride levels.

Lower concentrations, such as 2 mg/L and 3 mg/L, while still requiring careful management to avoid excessive fluoride exposure, are generally regarded as less likely to result in pitting, making 4 mg/L a significant threshold. In contrast, 5 mg/L would further exacerbate the risk of fluorosis, but the level identified as most likely for pitting is 4 mg/L. This understanding is essential for water treatment professionals to ensure safe fluoride levels in drinking water to protect dental health.