Final answer:
The patient's best opportunity to receive systemic fluoride is through tap water. Community water fluoridation is the most cost-effective method of delivering fluoride to prevent tooth decay.
Step-by-step explanation:
The patient's best opportunity to receive systemic fluoride is through tap water. Community water fluoridation is the most cost-effective and efficient method of delivering fluoride to prevent tooth decay. In the United States, approximately 75% of the population is already served by community water systems that contain enough fluoride to protect their teeth. Additionally, the US Environmental Protection Agency sets a maximum level of 4 ppm (4 mg/L) of fluoride in drinking water to prevent excess fluoride intake.