Biggest contributing factor: Juice!
I've written before about the great juice scam and how it directly relates to childhood obesity AND I can't stress enough that the juice you buy in the grocery store, especially the kind that comes in a box or pouch and is marketed to kids, is not a health food or a healthy choice. Even if you "water it down" it's still adding unnecessary sugar on their teeth and in their bodies.
One thought I had that was not covered in the story was the amount of sugar and sugar like products (High Fructose Corn Syrup) that are added to our food supply, it's in everything! It is almost impossible to find products from your grocery store without sugar ingredients like white/brown sugar, corn syrup, and maltodextrin, to name just a few.
What may be shocking to you is that Corn Syrup is a main ingredient in the top infant formula brands sold here in the United States. For example: The top five ingredients listed for Similac Sensitive Formula for Fussiness and Gas are: Corn Syrup Solids, Sugar (Sucrose), Milk Protein Isolate, High Oleic Safflower Oil, Soy Oil.
Which may raise the question: Is there sugar in breastmilk? The answer is yes, but it's not in the form of corn syrup or sucrose (table sugar), its in the form of lactose which is metabolized differently then the sugars found in formula. Without getting to technical the body breaks it down into two simpler sugars - glucose and galactose. Your body easily converts glucose and galactose is a valuable nutrient for brain tissue development. There are studies that show breastfed babies actually have higher IQ scores than formula fed babies later in life. If you are interested in how the body metabolizes sucrose and fructose see The Great Juice Debate.
Conclusion: Over the past 30 years our daily consumption of sugar has nearly doubled. So it should come as no huge surprise that tooth decay is becoming an epidemic in children as young as 1-2 years old across all income levels. What I find really interesting is the reasons for adding fluoride, a known neurotoxin, to our public water supply is not being substantiated given these new statistics from the CDC. Proving that there is absolutely no benefit to ingesting fluoride.