Note to insolent teenagers and brassy dames everywhere: Your chewing-gum habit, long a small emblem of your devil-may-care style, may now just be a sign that you're really into oral health. Sorry. Wrigley's Orbit, Extra and Eclipse sugarless gums will soon sport a seal of acceptance from the American Dental Association, reports USA Today. See the company's Web site www.gumisgood.com The ADA seal, which graces hundreds of products including Procter & Gamble's Crest and Johnson & Johnson's Listerine, was granted based on studies that suggest gum chewing reduced the risk of cavities. (See this one looking at more than 500 ...