With nearly 90% of adults unaware that tooth decay is the No. 1 chronic disease among children, Crest and Oral-B are doubling down their #ClosingAmericasSmileGap efforts with a new back-to-school campaign.   Between taking tests, trying to fit in and making the team, it’s tough being a kid. But it’s even harder for the millions of children without basic oral care supplies. For them, a toothbrush and toothpaste are more than just basic necessities: They’re game-changers when it comes to c...