What it means for a patient
- Fillers differ in how thick and stiff they are, and these properties affect how they behave after injection.
- Your injector can choose a filler to lift, support or shape an area based on these properties.
- This is a lab study of the gels themselves. It does not test results in patients.
- Ask which filler is planned for each area and why.
Why this paper matters
It gave a lab-based way to classify fillers by viscosity and elasticity. The authors state this lets clinicians choose fillers on scientific grounds and predict how they will lift, support and sculpt.
Overview
Two common types of facial filler are made mainly of calcium hydroxylapatite (CaHA) or cross-linked hyaluronic acid (HA). The authors wanted to give physicians a scientific basis for choosing fillers for volume replacement. They measured the viscosity and elasticity of seven filler gels in a lab instrument called a rheometer.
Findings
- Fillers tested: six cross-linked HA fillers (Restylane, Perlane, Restylane SubQ, Juvéderm Ultra, Juvéderm Ultra Plus, Juvéderm Voluma) and one CaHA filler (Radiesse).
- Viscosity and elasticity were measured by oscillation on a Thermo Haake RS600 rheometer, plate and plate geometry, 1.2 mm gap, 35 mm titanium sensor, 30°C.
- Measurements at 5 pascal over 0.1 to 10 Hz, read at 0.7 Hz, chosen as the most reproducible and relevant to stresses common in skin.
- The measurements support dividing current fillers into three groups.
- The abstract does not name which filler falls in which group or give the measured values.
Terms
- Rheology: the study of how materials flow and deform.
- Viscosity: how thick a gel is and how much it resists flowing.
- Elasticity: how well a gel springs back after being pressed; stiffness.
- Calcium hydroxylapatite (CaHA): mineral microspheres in a gel, used as a filler.
- Cross-linked hyaluronic acid (HA): a gel form of a sugar found in skin, bonded to last longer as a filler.
- Rheometer: a lab instrument that measures flow and stiffness.
- Soft tissue filler: an injectable used to add volume under the skin.