HA:
HA chains in solution naturally form entangled networks
Chains can disentangle and leave
Short duration
HAFILLER:
To maintain entanglement a few chemical cross-links are introduced
The links prevent chains from leaving
Long duration

 

 

Both can be degraded by the body.

But why use a biodegradable material?
A degradable material gives you freedom to adjust to;changes occurring due to aging; changes in fashion; changes in your own mind.