Long-term evaluation of porous PEGT/PBT implants for soft tissue augmentation

Porous PEGT/PBT implants with different physico-chemical characteristics were evaluated to identify its potential as biodegradable and biofunctional soft tissue filler. Implants (50 x 10 x 5mm(3)) were implanted subcutaneously in mini-pigs and tissue response, tissue volume generated and its consistency were assessed quantitatively with a 52 weeks follow-up. The absence of wound edema, skin irritation, and chronic inflammation demonstrated biocompatibility of all implants evaluated. The hydrophobic implants induced the mildest foreign body response, generated highest amount of connective tissue and demonstrated a decrease in copolymer MW of 34-37% compared to 90% decrease of the hydrophilic implants. The rate and extent of copolymer fragmentation seems to be the determining factor of success of soft tissue augmentation using porous PEGT/PBT copolymer implants.