The three crossword solutions for the term 'toothpaste ingredient' are WHITENER (8 letters), LYE (3 letters), and bner (4 letters). WHITENER is a common ingredient in toothpaste, usually in the form of hydrogen peroxide, which helps to remove surface stains from teeth. LYE is a type of alkali, also known as sodium hydroxide, which is used to help create a thick, creamy texture in toothpaste. Bner is an abbreviation for baking soda, which is a mild abrasive that helps to remove plaque and freshen breath. All three of these ingredients are commonly found in toothpastes.