Arm & Hammer parent company Church & Dwight Co. has agreed to buy the U.S. and Canadian oral care brands of Unilever NV for $104 million, plus additional performance-based cash payments of between $5 million and $12 million at a later date.The businesses, which include Mentadent toothpaste and toothbrushes, Pepsodent and Aim toothpaste, and the exclusive licensing rights to Close-Up toothpaste, recorded sales of $61 million in the first six months of 2003. Unilever put the brands up fo...