Puneet Nanda StoryPuneet Nanda was like many parents: He couldn't get his five-year-old daughter to brush her teeth properly. But unlike most parents, Nanda is a toothbrush manufacturer with an irrepressible entrepreneurial drive. Knowing that his daughter was fascinated by her sneakers with flashing lights, he ripped the lights out of her shoes and put them on a toothbrush. That didn't work, so "I went to Disneyland that evening and bought everything that lit up," says Nanda, now 38. The second prototype was more successful. His daughter brushed for a good two minutes before asking: "Dad, will this ever stop, or should I brush my teeth off?"Bingo. Nanda added a timer so the light would blink for exactly a minute, and the Fire Fly toothbrush was born. The brightly colored Fire Fly -- the newest version sports a see-through handle showing off a tiny toy and a bunch of floating glitter -- is making a name for Dr. Fresh, Nanda's Buena Park (Calif.) company and his medical school nickname. In 2004, Nanda got the original Fire Fly into Target, and by 2005 it was bringing in 20% of the 50-employee company's $25 million revenues.Nanda, who holds 58 patents, is seizing on the success of the Fire Fly to create other dental products with flashing lights. "I'm building brand equity," says Nanda. "If I have to do something I have to do it the best." He already has a foothold with more conventional wares, such as private-label dental floss sold nationally in Walgreens and Target stores.Nanda's path to dental success hasn't been easy. The New Delhi native left medical school to join the family toothbrush business in 1989, after his father had a heart attack. Two years later he began hawking toothbrushes to Russians who'd come to India looking for products to sell back home. Nanda moved to Russia in 1993, leaving his wife and son in India and selling toothbrushes out of a warehouse. He soon felt unsafe doing a cash business in Russia and returned to India for 18 months before heading to New York. Having little luck in New York, he tried Los Angeles, where he landed a $180,000 contract with a 99 cents store. "I'd never seen that big of a deal," says Nanda, who then moved his family to L.A.Nanda knew he needed something clever to grow in an industry dominated by heavyweights such as Colgate-Palmolive and Procter & Gamble. The Fire Fly may do the trick. It initially flopped at Walgreens, so Nanda began selling it directly to dentists he met at conferences. "The flashing light encourages kids to brush a little longer," says San Francisco pediatric dentist Bergen James, who gives it to her patients. "It gets children to brush, and it gets them excited about it."The positive feedback from dentists encouraged Nanda to recommit to direct sales. He hired 40 women in India to call dental offices in the U.S. and pitch the Fire Fly. And he kept knocking at Target's door, a company he'd been pitching since 2001. Once Target took it, Walgreens was willing to give the Fire Fly another try.Nanda now spends more than half his time ginning up new ideas. Next up: mouthwash and toothpaste with kid-friendly add-ons. If all goes well, that may turn Dr. Fresh into a big company with a lot of flash.More on doctors and business