Currently there are biological substances used as fillers primarily in the face to reduce or conceal small lines or imperfections in the skin. The areas in which the best results are obtained are:

• Lines between the eyebrows and on the forehead.

• Lines at the corner of the eyes (crow's feet).

• Creases from the cheeks to the lips (nasogenian folds).
  

• Wrinkles or fine lines at the corners of the lips.
  

• Outline, highlight and volume of lips.
  

Advantages. Fillers are non-surgical methods that can have a pleasing affect on the patient's appearance without the need for surgery. Their application is an outpatient procedure that can be safely performed in the doctor's office. It is a subtle way of improving one's facial appearance naturally. Nonetheless fillers are not a substitute for facial rejuvenation surgery when this is indicated (they do not remove the flaccidity of facial skin and muscles, eyelid bags or folds in the neck); that is, their usage is different, but in good candidates the results are noticeable and immediate.

Products. There are currently multiple substances used as fillers, some are synthetic and permanent and others are absorbed in two or three years, and are of natural origin. We recommend the latter, as they do not create any abnormal reaction in the body and are of biological origin. The most frequently used substance and that which has proven to be most suitable is with a doubt hyaluronic acid.

Hyaluronic acid. There are different commercial names but the active substance is the same. Hyaluronic acid is a substance that exists normally in the body, its principal function is the retention of water and it is a major component of the connective tissue matrix in the dermis. The advantage of this product is that it does not require previous tests to rule out allergic reactions. Youthful skin is rich in hyaluronic acid, but as it ages the function and distribution of this substance changes as the characteristic signs of aging appear. This product acts by enriching the natural reserves and reestablishing the lost volume, softening the signs of the passing of time.

Application. As with all plastic surgery procedures, the application of fillers must be performed by qualified and trained personnel, who must be judicious in its use and must assess each patient in accordance with four important parameters:

1. The type of product, as there are at least three different variants of hyaluronic acid, which depend upon the viscosity of the same to determine the best areas for application.
2. The anatomical site of application (between the eyebrows, crow's feet, cheeks, facial lines, lip augmentation).
3. The amount of product to be injected.
4. The depth of the application, that is, in the epidermis, hypodermis, or dermis.
   
   

This treatment is very useful and provides very good results; however if the product is not applied correctly it may leave abnormalities in the contour of the face, or overcorrections that can appear anti-aesthetic and are difficult to correct.