Demolish the children pureness?

When we visited Uros (the Floating Islands) in Peru, the tour guide introduced us to the people living on the islands. After that he told us not to give candy to the kids, as the dentist is far away on the shore and is expensive for the people there. I just realized that I had wrong thoughts before. We thought to give some candy to the children who live in the rural area when we visited poor countries; we thought it was bringing happiness to the children. Perhaps those children have a temporary happiness, but they might have to pay it back with tooth pain. Or, we bring something like pencils to the children, but it might further their greediness. I was met by kids who came toward me and asked for something. So, I have doubts, whether our things will make them happy or demolish their pureness?