Fillers, also known as dermal fillers or soft tissue fillers, are non-surgical cosmetic treatments used to restore volume and fullness to the face and other areas of the body. They are composed of various substances, such as hyaluronic acid, calcium hydroxylapatite, or poly-L-lactic acid, which are injected into specific areas to plump up the skin and smooth out wrinkles, folds, and fine lines.