A powered toothbrush refill head combines a typical round oscillating or primary tuft block which oscillates in a rotational manner with a secondary tuft block. The secondary tuft block may be oscillated in a rotational manner or may oscillate linearly back and forth in the same direction as the handle...http://www.google.es/patents/US7428766?utm_source=gb-gplus-sharePatente US7428766 - Powered toothbrush
