Dermal fillers are used to restore volume and fullness to areas of the face that may have lost elasticity due to aging or other factors. They are injected into specific areas to smooth out wrinkles, enhance lips, and define facial contours. The most common substance used in fillers is hyaluronic acid, which is naturally found in the body and helps maintain skin hydration and elasticity. Results can last from several months to over a year, depending on the type of filler used and the treatment area.