Flexing sides! A superior clean (with regular use vs. ordinary manual brush). Oral-B. Trust the brand more dentists use worldwide. How does Clinical Pro-Flex work Clinical Pro-Flex has flexing sides that adjust to the unique curves and contours of your teeth, including gumline, for superior clean vs. an ordinary brush (with regular use). Because of its flexibility, Clinical Pro-Flex is gentle on gums too. Also try Crest Pro-Health toothpaste. Made in Germany.;