Trade Article: The Filler Effect


*Sponsored Post*

*The brand name of this filler is omitted from this blog post for medical regulatory purposes as we are not allowed to mention brand names of injectables/scheduled medicines to consumers and patients (South Africa) as we promote blog posts on our media platforms*

Ask your doctor or distributor below for information on this filler

Dr Alastair Clark discusses a new line of fillers (distributed in South Africa by Genop Healthcare) specially designed for the mobile areas of the face.

More than reducing wrinkles and restoring volumes, the purpose of aesthetic medicine is to give the face a naturally attractive appearance – which is easily achieved with the use of facial injectables such as botulinum toxin type A and dermal fillers.

That said, it must be noted that while the current premium HA dermal fillers provide good results on the face in a static way, they are not evaluated for facial movements. This is because they were designed to only take into account the static outcome of the treatment – even though all the areas of the face are dynamic and are actually moving.

However, it is a challenge to design specific fillers taking the dynamism of the face into account. The implant must not only be able to stretch with the movements of the area, but also to resist multiple constraints in order to provide a long‐lasting effect.

Enter a new generation of filler

With this in mind, a leading laboratory and its team took up the challenge and was able to design, test and clinically validate a line of four gels that are specifically dedicated to the different dynamic areas of the face: The Resilient Hyaluronic Acid.

It’s the first gel designed by taking into account the movements of the face, and has two principles: Stretch and Strength.

Now, the first step of the challenge was to find a way to preserve the rheological properties of the natural long HA chains in a crosslinked network.

Natural hyaluronic acid is made up of long chains (up to 30 000 monomers) which confer its viscoelastic capacities. Thanks to these properties, hyaluronic acid maintains tissue architecture, volume and hydration.

During a classical crosslinking reaction, the HA chains are partially degraded, which makes them lose their very interesting natural rheological properties and requires a higher crosslinking rate (5‐10 %) to counterbalance this degradation. The obtained gel has, because of this high crosslinking rate, a rigid structure.

Based on their knowledge of HA and the reticulation reaction, they created the “preserved network” process to better protect the length of HA chains from degradation, while optimising the degree of crosslinking.

This way, the natural mobile interactions within the HA chains contribute to create a 3D network that is reinforced with anchor points with only limited amounts of BDDE (1.9‐4%). This resulted in the produced gels becoming resilient, instead of being quite static.

In summary, the “preserved network” method allows their solution to protect the HA, where less clippings of HA occur, and the natural chains of HA in the network are more preserved.

The result is that very little BDDE is needed to create a crosslinked HA with remarkable dynamic properties. This technology is now protected by several patents delivered or pending.

In addition, traditional monophasic fillers present a rigid structure at the molecular level with a crosslinker rate between 5 and 10% – while these gels present a higher dynamism at the molecular level with longer HA chains that can move in the network. These gels are stabilised with a lower crosslinker rate (1,9-4%).

This is particularly interesting because it suggests that these new fillers are more adaptable at the molecular level, and will thus integrate better once injected into the dermis.

The second and very important question was how to characterise the dynamic properties of the gels? The second step of the challenge was to confirm the dynamic rheological properties of these resilient gels. Although it was widely used up to now, the mere G’ measurement wasn’t sufficient to characterise the four gels.

Classical and static rheological parameters include:

  • The G’, or elastic modulus (static assessment) to measure the gel hardness,
  • The G’’ or viscous modulus to assess the resistance to flow of the gel,
  • The cohesivity index which is a valuable measure to test the resistance of a gel to compression as well as degradation, and finally,
  • The viscoelasticity index delta, a tool to evaluate the indications as well as the depth of injection of the gels

All these parameters are assessed using a unique and usually low constraint applied on the gels. Thus, these parameters are not able to assess its full behavior.

Combined with the measurement of the stretch capabilities (assessed by deformation by creep), they were able to fine tune the four gels to cover the requirements of the mobile areas at different injection depths. The stretch values represent the stretching capacities of a gel.

The brand name of this filler is blacked out above for medical regulatory purposes as we are not allowed to mention brand names on a media platform (South Africa)

Traditional fillers versus the resilient hyaluronic acid gels

If one compares the values of two fillers, for the same indication, one observes that the RHA gels not only have higher strength value (so that they better resist internal or external pressure in the long run), but they also have higher stretch capacity tht will translate into a better integration/positioning of the filler once injected.

These gels therefore have a better adaptability to the injected area, while being strong enough to resist to pressure when needed.

Traditional fillers on the other hand have a low stretch capacity. Once the patient performs a facial movement (smile for instance), these gels will « break » and create bundles that may lead to unaesthetic outcomes, lumps or bumps, or a feeling of the product by the patient.

On the contrary, the RHA gels (with their high stretch property combined with their strength) will be able to resist pressures and to adapt nicely to different facial movements. They actually become an integral part of the injected area, leading to very natural results without any irregularities, lumps, and bumps. Patients won’t be annoyed by the feel of products.

The selected four formulations offer a good palette to address the different facial areas:

  • RHA 1 for fine lines and superficial treatments – this is when a gel needs to be very subtle, soft, smooth and able to easily conform with movement in order to stay invisible,
  • RHA 2 for moderate wrinkles – for use in dynamic areas and for where volume creation is needed so the gel needs resistance to pressure,
  • RHA 3 for severe wrinkles – for when strength must be higher,
  • RHA 4 for volume creation in an extended area – this is where we want to limit the gel deformability by keeping highest resistance to compression: Stretch decreases while strength is kept maximal.

Take home message

These four fillers are very well adapted with their high stretch property to areas where movements are key, but also to resist in areas where pressure may be high with their strength capacity.

With this new method of cross-linking, the gels are more dynamic at the molecular level. This will translate into unique resilient properties at the rheological level (stretch and strength) that will lead to immediate and long lasting results without safety issues.

With its two principles: Stretch and Strength, this is the first gel designed by taking into account the movements of the face.

For more information on these fillers distributed by Genop Healthcare, contact them below:

*The brand name of this filler is omitted from this blog post for medical regulatory purposes as we are not allowed to mention brand names of injectables/scheduled medicines to consumers and patients (South Africa) as we promote blog posts on our media platforms*

Ask your doctor or distributor below for information on this filler


Email: Glynis Watkins

A2 Disclaimer: This article is published for information purposes only, and should therefore not be taken as an endorsement –  nor should it be regarded as a replacement for sound medical advice. 

A2 Trade Magazine 2018 – Issue 3

This article was written by Dr Alastair Clark and edited by the A2 team EXCLUSIVELY for the A2 Aesthetic & Anti-Ageing Magazine May TRADE 2018 Edition (Issue 3). 

A2 Magazine prints only one trade magazine each year – this fifth issue of A2 is for doctors and medical professionals only and is not available for sale in stores or to the general public.

Feature content is naturally focused on innovations, techniques and trends in the aesthetics and anti-ageing industry, for the sole purpose of providing medical professionals in this field with information including new technologies and products available.

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About Author

Dr Alastair Clark (M.B, B.Ch, GPSI Cosmetic Dermatology and Aesthetic Medicine) is a member of the A2 Aesthetic & Anti-Ageing Expert Panel. For more info on this doctor, please click on the link to the right hand side of this box.

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