In vivo preclinical efficacy of a PDLLA/PGA porous copolymer for dental application

This study aimed to analyze surface morphology and physical-chemical properties of a copolymer of polylactic/polyglycolic acid (Fisiograft, Ghimas SpA, Casalecchio di Reno, Italy) by scanning electron microscopy (SEM), porosimetry, and rheological analysis. Then the material was implanted in vivo to test its efficacy at promoting bone healing and new bone formation in postextraction sockets. Under general anaesthesia, sockets were created in 12 minipigs and then randomly filled with the porous copolymer in SPONGE or GEL form and compared with commercial BioOss (Geistlich Biomaterials) and Biocoral (Inoteb, France). At 15, 30, and 60 days from surgery, the newly formed trabecular bone quality was evaluated by means of histology and histomorphometry. The SEM and rheological analyses performed on GEL showed a surface microporosity and a rheological shear thinning behavior, whereas the SPONGE porosimetric measurements revealed larger pores. At 15 days, the new bone regrowth was observed in all treated sockets but appeared immature, as the trabeculae were very dense and thin. At 30 days, GEL and SPONGE were degraded, and the sockets were filled with bone that, in terms of bone volume fraction, trabecular number, and separation, was not statistically different from normal bone.