Hyaluronic Acid (HA) Fillers

Intrinsic and extrinsic factors influence our aging process. The speed and extent of our aging varies with individual genetics and also can be influenced by factors such as smoking, alcohol abuse, chronic sun exposure, stress, chemical exposure, and rheumatologic disease.   

When properly performed by a skilled practitioner, rejuvenation with dermal fillers is simple, with a high patient satisfaction, and low rate of complications. 

In my practice, I like to use the dual plane technique. Deeper plane will be injected with high G filler and superficial plane will be injected with moderate to low G filler. The best filler results can be achieved with two visits, deeper injection first to act as "pillars" to create a lift, then the second injection visit in about 4 weeks using superficial injection to build the "bridges" to reconnect the pillars to create a smoother appearance. 

Again, not all fillers are created equal, in experienced hands; the best approach is patient-oriented, based on patient's anatomical structure and their individual needs rather the brand name or the cost of the fillers.  

Collagen and Elastin: 

• The quantity and quality decline in the dermis, resulting in skin laxity and thinning
• Deep in the skin, atrophy occurs at the subcutaneous fat causing underlying tendons and bone prominences to become visible

Hyaluronic Acid as dermal filler: 

• First came available in 2003 as a glucosaminoglycan biopolymer composed of strands of repeating chains of d-glucuronic acid and N-acetyl-d-glucosamine
• It is a highly encountered component of extracellular matrix in humans and other species
• HA is present in the skin, synovial fluid, muscles, and vitreous body the eye, and more
• It is a lubricant and important structural component of tissue, making it extremely hydrophilic 
• HA is highly biocompatible with low incidences of antigenic adverse events
• Native HA is low in viscosity and short half-life
• For increased duration, manufacturers of HA fillers incorporated cross-linking agents to make the product dense and durable enough as effective filler agents
• Firmness and longevity of commercially available HA vary according to concentration of HA, molecular weight of HA, and extent of cross-linking. 
• Duration ranges from 6 months to 2 years
• HA fillers are most popular dermal fillers due to ability to dissolve (within 24 hours) with commercially available hyaluronidase

How to pick a HA filler:

Three popular HA filler brands:

1. Restylane family
2. Juvederm family
3. Revaness Versa (Newest)

Picking the right filler for you depends on:

1. Where the filler is being injected
2. What type of improvements you are wanting 

• HA fillers are characterized by their rheological properties, viscoelasticity and cohesivity of the material. 
• Viscoelasticity: the hardness or softness of a gel and defined by its elasticity, meaning how the filler is able to retain its shape when force is applied, and viscosity, how the filler resists gradual deformation by shear stress. 
• The higher the G*, the higher the resistance to deformation ans cpacity to keep its shape (aka a major lifting effect)
• Cohesivity: the property of a gel to stick together when external force is applied. Gels with higher cohesivity tend to uniformly infiltrate tissue and are not fractionated by movements.