A filler is a biocompatible material that is implanted to correct a wrinkle or to modify the shape of a specific anatomical area. Very fine needles or small-diameter cannula are used to position hyaluronic acid or calcium hydroxylapatite at different depths, according to the desired result. To increase the volume of the cheekbones, for example, the implant needs to made onto the cheekbones, whereas to correct the wrinkles around the nasolabial fold, the implant needs to be made into the skin. All the materials used are absorbable, in order to avoid the unpleasant and sometimes very serious adverse effects that are frequent when non-reabsorbable materials are used. Choosing materials of different viscosities also enables very fine wrinkles to be treated, or sizeable and long-lasting increases in volume to be obtained.