What is true about a properly placed sealant over small initial carious lesions?

A properly placed sealant over small initial carious lesions can help in reducing the number of bacteria present. Sealants create a physical barrier that protects the pits and fissures of teeth from food particles and bacteria, which in turn limits the progression of caries. This can lead to a decrease in the bacterial load over time, as the sealed area is less accessible for bacteria to thrive and cause further decay.

The sealant does not provide immediate pain relief—pain from carious lesions is often due to pulp involvement or sensitivity, which sealants do not address directly. Similarly, while sealants can effectively halt the progression of cavities, they are not considered a permanent solution and may require monitoring and adjustments over time, especially to ensure they maintain their sealant properties. The need for more frequent replacement also depends on factors such as wear and patient habits, but it is not inherently required just because a sealant is placed.

Thus, option A accurately captures the beneficial impact of sealants on the bacterial environment of small carious lesions.