Final answer:
In the early 1930s, higher concentrations of fluoride in the water contributed to fewer cavities among people in the southwestern U.S. Fluoride enhances dental health by forming fluorapatite in teeth, which protects against acid attacks. Community water fluoridation is a cost-effective method to deliver fluoride and prevent tooth decay. The correct answer is option A).
Step-by-step explanation:
In the early 1930s, it was observed that people living in the southwestern U.S., where the water naturally contained high concentrations of fluoride, had fewer cavities.
The mineral fluoride is released naturally from rocks into the soil, water, and air. While all water contains some fluoride, only some groundwater and natural springs have high levels of fluoride, which are beneficial for dental health. Fluoridation is the process of adjusting the fluoride levels in water to prevent tooth decay. Fluoride ions in water help protect teeth by forming fluorapatite which is more resistant to acid attacks and is less soluble than hydroxylapatite, the original material of tooth enamel.
Community water fluoridation has been identified as the most cost-effective method for delivering fluoride to the population, reducing tooth decay by 25% in children and adults. Notably, the United States had a national goal for 80% of Americans to have access to optimally fluoridated water by 2020 to prevent tooth decay.