I was in public school from 1943 to 1956. I have no recollection of K thru 6, so I imagine my mother who avoided sugar mostly sent a lunch with me. Then I went to a combined junior/senior high school where we had lunch, including pie or cake every day. I got about one cavity a year there, none previously. Off to university where living in a dormitory I got breakfast, lunch and dinner, with sweet rolls, cake, pie, ambrosia, bread pudding, and other sweets at every meal. Got six more cavities in one year. Then I moved to off campus housing where I did my own cooking with very little sweets and got NO more cavities for many years except for failed fillings. Don’t give your children sweets and save their teeth. I let my children have sweets, at Halloween, Christmas, Easter and their birthdays, and they had no cavities at all into adulthood. They are now early 40s, one got a cavity behind an impacted wisdom tooth. The other needed dental repair work from cracked tooth, which the dentist said might be from his 82nd Airborne days.
You’re right, of course. Like your children, mine had candy only on special occasions but not at other times. They never had cavities, either. But then, this past year, I started buying a type of sticky candy that became their favorite, and the firstborn ended up with one cavity right before heading to college.
I’m sure sugar is not good for us - but I’ve baked lots of good things and my children have had sugar all of their lives and never had a cavity - ever. They are now 28 and 23 and are consistently told they do a good job of flossing and brushing by their dentists.