Actually, the fact that dairy and calcium will bring up strong bones is a myth. In the long run it actually causes the opposite. America has the highest rate of dairy drinking than any other country, and also the highest rate of osteoporosis, which is basically weak/thin bones. In fact, there are many reasons why we should not be taking in milk products.
1. Milk doesn't reduce fractures. Contrary to popular belief, eating dairy products has never been shown to reduce fracture risk. In fact, according to the Nurses' Health Study dairy may increase risk of fractures by 50 percent!
2. Less dairy, better bones. Countries with lowest rates of dairy and calcium consumption (like those in Africa and Asia) have the lowest rates of osteoporosis.
3. Calcium isn't as bone-protective as we thought. Studies of calcium supplementation have shown no benefit in reducing fracture risk. vitamin D appears to be much more important than calcium in preventing fractures.
What I'm saying is that there could be a variety of factors why your teeth right now are prone to tooth decay with eating sugar. It could just be in your famly. You have to make sure you are brushing your teeth thoroughly after every meal, if you can. I don't think it's because you didn't drink dairy as a child. It's a good thing you are avoiding dairy.