Dermal fillers are #2 behind Botox as the most commonly sought after and administered medical aesthetic treatment. Botox may have a topical preparation lurking and potentially replacing it. Not so with dermal fillers; they are here to stay. It has now over 12 years since Restylane was FDA approved (December, 2003) and it would appear as though Ellanse will be the next dermal filler to hit the US marketplace. Dermal fillers are very popular. The reasons are obvious. They offer a safe and effective way to bring youthful results without expensive cosmetic surgery. Most patients who have had dermal fillers are happy and come back for more.

However, with the arrival of new dermal fillers and different formulations it can be difficult to determine which filler works best for each ‘wrinkle.’ Dermal fillers are approved by the FDA for treatment of specific areas of the face. Radiesse was approved by the FDA for treatment of naso-labial folds back in 2006. Nine years later in 2005 it received an approval for “improvement of volume loss on the dorsum (back) of the hands.” Dermal fillers are FDA approved for certain areas with other uses designated as ‘off label’ uses.


The FDA and ‘off label uses

Regarding the “off label use” of dermal fillers. There is nothing wrong with a doctor injecting into an area other than the FDA approved area. Mark Jewell, MD, author of Safety with Injectables Workbook agrees. He says, “Off-label use is legitimate, it’s something a doctor discusses with the patient to meet the patient’s specific needs.” So provided the injector is experienced and the doctor and patient are in agreement, there is no problem injecting into areas that are ‘off label.’ It is important to note, however, that advertising off label uses should not occur.


Dermal fillers injection results are very injector-dependent. There is no other area of medical aesthetics where the experience, technique and artistic ability of the doctor, nurse or aesthetician are more important. Obtaining a beautiful and natural result has more to do with the ability of the injector than what filler is injected. Dermal filler injection is the most artistic realm of medical aesthetics. Here are the areas of the face that most people look to correct.


Need-To-Know Dermal Filler Factors

Certain factors need to be understood to deterine why certain fillers work better in certain areas of the face. These include the primary ingredients, cross-linking, particle size, concentration and G-prime.

Primary Ingredients


Hyaluronic Acid

Hyaluronic acid is a natural substance found in body tissues. It is a glycosaminoglycan that is present in the highest concentrations in connective tissue, cartilage, joint fluids and skin. Hyaluronic acid fillers draw water to themselves. This helps to increase the longevity of the filler provided the individual remains well hydrated. Dermal fillers composed of hyaluronic acid include Restylane, Juvederm, Belotero, Elevess, Prevelle, and Evolence.

Calcium Hydroxylapatite

Calcium hydroxylapatite is a mineral-like substance found in human bone. It is the heaviest of all dermal fillers. While hyaluronic acid fillers are clear in appearance, calcium hydroxylapatite appears milky white. A benefit of injection of this type of dermal filler is that it stimulates collagen formation. The primary example of a Calcium Hydroxylapatite filler is Radiesse.

Poly-L-Lactic Acid (PLLA)

PLLA is a synthetic dermal filler that is injected ‘throughout’ the face. In doing so, similar to Radiesse, it stimulates the production of collagen. This filler is different than other fillers in that it does not produce immediate results. Rather, through the stimulation of collagen formation in the dermis, the results appear gradually over several months. Sculptra is the only FDA approved PLLA dermal filler.

Polymethyl-Methacrylate (PMMA)

PMMA fillers are composed of PMMA microspheres suspended in purified collagen gel. Months following injection the gel breaks down and is replaced by your body’s own collagen. This is commonly referred to as a ‘semi-permanent’ filler but in truth it should be thought of as permanent. PMMA is not metabolized so in-effect it is permanent. An example of this filler is Bellafill. This filler is associated with lumps, nodules, granulomas and requires many injections. I do not recommend it. There are far better options.

Cross Linking

In the discussion of hyaluronic acid fillers, cross-linking is of particular interest. The natural liquid form of hyaluronic acid is quickly metabolized by the body in less than 24 hours. Cross-linking transforms the liquid form of hyaluronic acid to a gel form. Cross-linking dramatically slows the body’s ability to metabolize the hyaluronic acid. Hence, the cross-linked hyaluronic acid fillers will last many months. Dermal fillers with more cross-linking of hyaluronic acid last longer.

Particle Size and Concentration

As a general rule, dermal fillers with higher concentrations and particle sizes tend to be better for deeper injections. A dermal filler with a higher concentration is typically felt to last longer. For instance, Restylane has a concentration of 20mg/ml while Juvederm Ultra’s is 24mg/ml. However, Restylane comes in a 1.0 ml syringe while Juvederm Ultra is a 0.8ml syringe.

Dermal filler concentration is commonly described as ‘particles per ml.’ More particles per ml equates to a smaller particle size. Larger particles tend to last longer and are better for deeper injection. As an example: Restylane’s concentration is 100,000/ml, Restylane Lyft’s is 10,000/ml and Restylane Silk’s is 500,000/ml. Clearly, Lyft is better for deeper injection while Silk would be preferable for more superficial injection to delicate areas.


A dermal filler with a higher G-prime is thicker, heavier and ‘harder.’ They are more resistant to disintegration however may be more painful to the patient when injected. Dermal fillers with a higher G-prime are typically injected deeper into the dermis. They are better suited for injection into deeper folds such as the nasolabial fold or for increased cheek volume. I prefer fillers with a higher G-prime when I desire a ‘lifting’ effect in the cheek area. It is important to note, however, that simply having a higher G-prime does not necessarily equate to a better ‘lifting effect.’ A product such as Juvederm Voluma has a G-prime lower than other dermal fillers yet has an excellent lifting effect. In truth, the lifting effect involves several factors including G-prime, concentration, and ability of the filler to intertwine (or ‘grab’) surrounding tissues. Although Juvederm Voluma has a lower G-prime, it has a superior ability over many other fillers in its ability to intertwine with surrounding tissues. Examples of higher G-prime fillers include Radiesse and Restylane Lyft. Dermal fillers with a lower G-prime are thinner and lighter. They are better suited for injection into delicate areas such as the tear troughs, lips or other superficial wrinkles. Examples include Restylane Silk and Belotero.

The Tyndall Effect

This is an effect that can occur with some hyaluronic fillers when injected superficially. This effect is the result of light reflecting off of the filler giving a bluish hue. We know hyaluronic fillers all have distinct cross-linking, concentrations, particle sizes and G-primes Fillers with more cross-linking and a higher G-prime are better suited for deeper injections to add more volume. They are also more likely to produce a Tyndall effect thus should not be injected superficially. Belotero boasts that its low G-prime and variable cross-linking attributes make it stand alone as the only filler which can be injected superficially and never result in Tyndall effect. I do agree with this. However, the presence of the Tyndall effect is something exceedingly rare in my experience. The likelihood of this effect occurring increases the more superficial the filler is placed. I have seen case reports of these occurrences. In most cases it appears as though the filler was placed at the top of the dermis or even intra-EPIdermally.

All these features of dermal fillers can indeed get confusing. Essentially, dermal fillers with larger particles, higher concentrations, higher G-prime and more extensive cross-linking tend to last longer, be bulkier, ‘stickier,’ add more volume, and are better suited for deeper injection into the dermis. Examples: Radiesse, Juvederm Voluma and Restylane Lyft. For fine and delicate and more superficial injection, fillers with a smaller particle size, lower concentration, less crosslinking and a lower G-prime are preferable. Based on these factors the following guide gives you my preference for which dermal filler ideally should be placed where. The choice of dermal filler relies heavily on the preference of the doctor and experience of the patient and injector. Some fillers shouldn’t be placed in certain areas however. For example, the consistency of Radiesse makes it an excellent choice for cheek augmentation but makes it a terrible choice for lips.

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