Final answer:
Leo Gerstenzang invented the cotton swab in the 1920s after seeing his wife use cotton-tipped toothpicks.
Step-by-step explanation:
Leo Gerstenzang created the product known as the cotton swab in the 1920s. The idea came to him after he observed his wife placing cotton on toothpicks for cleaning purposes. The innovation of the cotton swab marked a significant advance in personal hygiene and has since become a common household item worldwide. While the history of oral care products includes chew sticks and the mass production of toothbrushes, the creation of the cotton swab by Gerstenzang stands as a distinct contribution to modern hygiene practices.