Calcium hydroxide is a colorless white powder and is obtained when calcium oxide (called lime or quicklime) is mixed, or slaked with water. It has many names including hydrated lime, caustic lime, builders' lime, slack lime, cal, or pickling lime. Calcium hydroxide is used in many applications, including food preparation. Calcium hydroxide has many medical and industrial uses. It is in many dental formulations, especially for root canal filling.