Certain wrinkles can be filled, whereas others require an additional, more specific treatment (botulinum toxin for the expression wrinkles on the forhead, facial peels for very 'crumpled' skin and support threads for the marionette lines resulting from sagging).
The crucial question is that of the quality of the product used for wrinkle filling and its lifespan. Absorbable or Long-lasting?

'RAPID' ABSORBABLE (a few weeks to a few months)

• Collagen (ZYDERM®, ZYPLAST®, etc.) is bovine in origin - and therefore due to be phased-out - and two allergy tests are required beforehand. A synthetic version exists (COSMODERM®).

• Hyaluronic acid (HYLAFORM®, RESTYLANE®, PERLANE®, JUVEDERM®, etc.), now synthetic in origin,
  does not require tests to be conducted. Its lifespan varies according to the degree of crosslinking of the product and pharmaceutical companies often offer three levels of polymerisation of the molecules in order to offer varying degrees of fluidity.

'SLOW' ABSORBABLE (6 months to a few years)

• Polylactic acid (NEW-FILL®) is an absorbable substance that lasts well, allowing both larger volumes (cheekbones, folds) and finer lines (not too close to the surface) to be treated.
• Polyacrylamide(OUTLINE®), presented as a slow-absorbing product by the company that produces it.
• Calcium Hydroxylapatite (RADIESSE®), useful for padding close to the bone (cheekbones, nose, hands), but cannot be used
  on the lips.
• Polyethylene glycol (REMAKE®), recently arrived on the market, seems to present a good lifespan and can be injected
  into the lips

LONG-LASTING (several years)

• Silicone is an old product (has been around for 50 years), its use has currently been suspended. It gives a remarkable 'volume effect' and is extremely well tolerated by the body's tissues, but it requires a gradual
  and perfectly-executed injection technique. It was not suitable for all areas of the body. It is important to mention it and to recognise its existence, since it is present in a very large number of patients.
• Composites, mixture of poly(methyl methacrylate)  with a collagen (ARTECOLL®) or hyaluronic acid (DERMALIVE®, DERMADEEP®) type vector, have been responsible for a very large number of problems, often over a delayed period of time (1 to 2 years).
  Avoid at all cost!
• The polyacrylamide gels (AQUAMID®, BIOALCAMID®) present the advantage that they give persistant volume and are extractable simply by applying pressure, since they do not combine with any of the tissues of the body.

TECHNIQUE AND SIDE EFFECTS

The injections, which are very precise, are performed under brief local or regional anaesthetic and their depth depends on the product used.
The number of sessions varies according to the product used, which in turn varies according to the area treated.
Bruising occurs especially in the area around the lips on the first injection. They can be disguised with specific covering products and their resorption can be speeded up by using ointments.

CONCLUSION

The filling of wrinkles is an essential step in the process of rejuvenating the face and we currently have at our disposal satisfactory products, nonetheless requiring a very good injection technique.