I used to do the same those days by dishing out pens and stuff to kids thinking i am doing them good. After my RTW trip and i see the after effects of our "kindness", it makes me have 2nd thoughts.
For example, when in the highlands of guatemala, there were many cases of missing children (the kids are really adorable and have rosy cheeks) and I was told that with tourists giving out freebies might have open up an opportunity for bad fellows to lure kids away with "presents". unfortunately at that time, many foreigners were view suspiciously and I was very careful about approaching the kids for a chitchat or photo taking..but then again, who can blame them for being wary?
You are right about not giving sweets as these people living in the countryside or mountains barely have enough money to keep the household going, much less dental treatment. Think we give them additional problems when tooth decay arises.
Once while travelling in mexico, i met this old american Couple at a popular tourist spot who were taking a rest after a long walk up a monument. As usual, there were tons of souvenir vendors and many have their babies and kids with them. there was a little girl who was just playing there, she wasnt begging nor asking for anything but this old chap whisk out a lollipop from his bag and went chasing behind the little girl to give it to her...WTH? In my heart, i was thinking, if you want to save the world, give some help to them, maybe you should have buy some souvenirs from her mother instead of giving her kid lollipops? who is going to provide her with toothbrush, toothpaste and even dental care?
I couldnt stop myself and so i voice out to them while trying not to offend them too.
Of course i got a dirty look from the wife who pull her husband away and muttering under her breath - ha.. must be scolding me la!
what I did for my recent Myanmar trip was I pre-packed clothes, coloured pencils, pen, books and stuff, got a driver when in Bagan and went searching for a monastry with an on site school/orphanage. i think it is better we donate to the village head, monastry, teachers or parents rather than the kids.