Which primary contaminant is often added to water to prevent tooth decay?

Fluoride is commonly added to drinking water as a means to prevent tooth decay. This practice, known as water fluoridation, has been supported by numerous studies showing that it significantly reduces the incidence of cavities in both children and adults. Fluoride works by strengthening tooth enamel, making it more resistant to acid attacks from bacteria present in the mouth. This mineral also has the ability to reverse early decay by remineralizing enamel.

The addition of fluoride to public water supplies is a public health measure aimed at improving dental health across communities, especially in areas where natural fluoride levels are low. It is important to maintain the right balance, as excessive fluoride can lead to dental fluorosis, a condition that can cause discoloration of teeth.

In contrast, lead is a harmful contaminant that poses severe health risks and is not added to drinking water; chlorine is primarily used for disinfection purposes but does not prevent tooth decay; and nitrates generally do not contribute to dental health and can be harmful when present in high concentrations, particularly affecting infants.