Final answer:
The value of water fluoridation in preventing tooth decay can be seen through its reduction in dental caries, cost-effectiveness, and safety and efficacy.
Step-by-step explanation:
The dental hygienist emphasizes the value of water fluoridation as the most significant contribution of dentistry to public health for several reasons. Firstly, water fluoridation helps in reducing dental caries, or tooth decay, by 25% in both children and adults. Fluoride, the main active ingredient in toothpaste and added to tap water, helps in remineralization and strengthening of tooth enamel, making it more resistant to corrosive acids produced by oral microbes. Secondly, water fluoridation is cost-effective compared to other fluoride-containing products, such as toothpaste and mouth rinses. Finally, water fluoridation has been proven to be safe and effective in preventing tooth decay.