Somewhere in Asia, a seller of toothpaste is especially happy these days. And not only because the second annual National Dental Health Month just ended in the Philippines. While that undoubtedly was good for business, even better was what happened last weekend in Manila. In bright sunshine in a public park, an estimated 10,800 schoolchildren clad in white T-shirts and cherry-red baseball caps assembled in long lines - all with one hand raised high and clutching a toothbrush. On cue, each lowered the hand and scrubbed away vigorously at his or her molars, incisors, and bicuspids for roughly three minutes, grinning self-consciously as white foam dribbled onto their chins and news photographers recorded the occasion for posterity. If you haven't guessed, the whole thing was an effort to win a new listing in the Guinness Book of World Records for "most people brushing their teeth simultaneously." Until the folks at Guinness accept it, they'll continue to recognize the mark set in China back in 2003 by 10,240 people.