What is the best injectable dermal filler for facial rejuvenation?
There is a plethora of products that are being used as dermal fillers to smooth lines, depressions, and/or wrinkles in the face. In the US, the FDA regulates sale and promotion of these substances. Many available injectable fillers are not sold in the US due to lack of FDA approval. Amongst the FDA approved filler agents, the major indication for use is correction of naso-labial folds. However, physicians are allowed to inject dermal fillers into other parts of the body following a thorough discussion with patients, as an off-label use of the filler. The fillers can be broadly classified to synthetic and natural. The synthetic products tend to last longer, but are considered to be at higher risk for lumping or migration.
It must be kept in mind that since the commonest indication for injectable fillers is cosmetic improvement of lines and wrinkles, as opposed to other medical drugs and devices that are developed to treat or prevent maladies or deformities. The safety profile of filler agents is therefore specially important. A list of most common dermal fillers is provided, with my own thoughts and conclusions reserved for the last paragraph.
Silicone Fluid: Dow Corning introduced medical grade silicone in the 1950’s for soft-tissue augmentation. The FDA banned the use of silicone as a soft-tissue filler in 1967 due adverse reactions. However, silicone continued to be approved by the FDA for use inside the eye, as treatment for treat retinal detachments. The FDA Modernization act of 1997 allows the off-label use of silicone to augment soft tissues. A new micro droplet injection technique has greatly reduced adverse reactions, such as migration and inflammation, seen earlier. Silicone is classified as a permenent filler.
Bovine Collage (Zyderm and Zyplast): Zyderm and Zyplast were introduced in 1981 and 1983 respectively. They are comprised of collagen fibers which have been extracted from the hide of specially designated cows. The clinical effect of bovine collagen lasts from three to four months. Bovine collagen is one of the safest fillers on the market. However, collagen use has waned due to availability of longer lasting alternatives. Collagen injections need to be preceded with a skin test, due to 3% risk of allergic reaction.
Hyaluronic Acid (Restylane, Juvaderm Ultra, Perlane, Juvaderm Ultra Plus): Hyaluronic acid is naturally found in all living beings as a polysacchride (a complex sugar) molecule that binds water in the space in between cells. In humans, the molecules in broken down and replaced within one to two days. The manufacturers have been able to prolong longevity of the hyaluronic fillers, through a process known as cross-linkage. Currently, hyaluronic acids are the standard of injectable dermal fillers. They last between six to nine months, and exhibit very few adverse effects. Hyaluronic acid fillers are the only fillers that can be immediately reversed by injection of an enzyme known as hyaluronidase.
Polylactic Acid Microspheres (New-Fill/Sculptra): Sculptra (formerly New-Fill) is a suspension of microspheres composed of poly-L-lactic acid (same as some absorbable sutures) suspended in methylcellulose. It was introduced in Europe in 1999, and in the US in 2004. The suspension in diluted with sterile water before injection into the face. Typically a series of 2 to 3 injections are necessary to achieve the desired effect. Results last up to two years. In the US, the FDA has approved the use of Sculptra for treatment of HIV related lipodystrophy (loss of facial fat in HIV patients secondary to anti-viral medications). Sculptra was recently approved by the FDA as a facial filler for cosmetic use in the general population (not just HIV patients) in July 2009. There have been reports of palpable nodules with the use of Sculptra, but problems have diminished with newer injection techniques. Sculptra should not be used in the lips.
Calcium-Hydroxylapetite Microspheres (Radiesse): Radiesse is a white, paste-like suspension of calcium hydroxylapetite (the substance present in bone and tooth) which gained FDA approval for injection into the nasolabial folds in 2006. It is commonly used in off-label fashion to augment cheeks and enhance the midface. Radiesse dose NOT form bone when injected into skin. It usually lasts one year in the body. Use of Radiesse in the lips is discourage as it can form a lumps due to action of muscles.
Polyacrylamide Gels (Aquamid and Bio-Alcamid): Polyacrylmides are polymers of a water solulable crystal which is used in soft contact lenses, and Gro-Beast toys. Aquamid is approved in Europe and Bio-Alcamid is approved in Europe, Israel, and Mexico. Polyacrylmides are not approved by the FDA for use in the US. In Russia and China, Polyacrylmide gels have been injected in large quantities for breast, buttock, and calf augmentation, and in facial lipodystrophy. The duration has been variously reported as form one year to twenty years, depending on the injected volume. Its clinical behavior is similar to liquid silicone. There have been a relatively large percentage of complications with this filler. Complications such as migration, granuloma (swelling and nodule formation), and infection.
Polymethylmethacrylate Microspheres (Arteplast/Artecoll/Artefill): Artefill, formerly Artecoll, is a 20% suspension of polymethylmethacrylate microspheres (tiny glass beads) in bovine collagen. The bovine collagen is resorbed by the body after four months, but the polymethylmethacrylate microspheres persist and become encased by fibrous tissue to give a sustained result. Due to presence of bovine collagen, as a carrier for the microspheres, patients need to be pre-tested to ensure absence of allergy to bovine collagen. Artefill gained FDA approval as a dermal filler in October 2006. However, the company stopped production in November 2008, due to disappointing sales results. There had been concerns regarding complications such as granuloma (lump) formation or infection with this “permanent filler”.
Poly-Hydroxymthyl-Methacrylate Particles (Dermalive/DermaDeep): Dermalive is similar in its chemical structure to Artefill. Dermalive is a 40% suspension of resorbable poly-hyroxyethyl-methacrylate fragments mixed in hyaluronic acid. It was introduced in Europe in 1998. It is used only for deep injections, as superficial injections caused a high incidence of granuloma formation. This product is not FDA approved and not sold in the US. Some doctors have brought the product into this country and advertise its use.
Bottom Line: The long list above is still incomplete in regards to all the available options for injectable dermal fillers. Most products gain regulatory approval in Europe, Asia, or Canada before achieving FDA approval. This should give us a level of comfort to know that the FDA sets the bar very high for approving dermal fillers.
I recommend that only products with FDA approval be considered for injection, as such products have passed a rigorous regulatory process. Although “permanent fillers” promise a lasting solution to wrinkles, the long term effects are not known for many such products.
I, therefore, prefer long lasting but non-permanent fillers with proven track record such as hyaluronic acid products (Restylane, Perlane, Juvederm, or Juvederm Ultra Plus) or calcium hyroxylapetite (Radiesse).