The crossword solution for the term ORG. CONCERNED WITH DECAY is ADA, which stands for American Dental Association. The American Dental Association is a professional organization of dentists that was founded in 1859 and is headquartered in Chicago, Illinois. The organization's mission is to promote oral health, advance the profession of dentistry, and provide resources to its members. The ADA also works to prevent tooth decay and other dental diseases through public education and research.