Final answer:
High caries risk is the primary indication for sealant placement to prevent cavities.
Explanation:
High caries risk is the best indication for sealant placement. Sealants are protective coatings applied to the chewing surfaces of teeth to prevent cavities, and they are especially beneficial for individuals at high risk of developing caries.
Factors such as the presence of good oral hygiene play a role in maintaining overall oral health but are not a primary indication for sealant placement.
Fluoridated water helps prevent cavities by strengthening enamel, but it is not specifically an indication for sealant placement. Similarly, a partially erupted tooth does not necessitate sealant placement as sealants are typically applied to fully erupted teeth.
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