Regenerative capacity of well-preserved blood clot may be enhanced by biologics like enamel matrix derivative (EMD). This retrospective analysis compares outcomes reported by three centers using different heterografts. Center 1 (C1) treated intrabony defects combining cross-linked heavy weight hyaluronic acid (xHyA) with a xenograft, Center 2 (C2) used EMD with an allograft combination to graft residual pocket. Center 3 (C3) combined xHyA with placement of resorbable polymer membrane for defect cover. Clinical parameters, BoP reduction and radiographically observed defect fill at 12-months examination are reported. The 12-months evaluation yielded significant improvement in PPD and CAL at each center (p<0.001, respectively). Analyses of Covariance revealed significant improvement of all parameters, significantly greater CAL gain disclosed C2 vs. C1 (p=0.006). Radiographic defect fill presented with significantly higher scores for C2 and C3 vs. C1 (P=.003 and =.014; C2 vs. C3 P=1.00). Gingival recession increased in C1 and C3 (P=1.00), while C2 reported no GR after 12-months (C2:C1 P=.002; C2:C3 P=.005). BoP tendency and pocket closure rate shared similar rates. Within limitations of the study, data comparison indicated that xHyA showed similar capacity to enhance regenerative response, as known for EMD. Radiographic follow-up underlined xHyA staying alone role in new attachment formation.

A heterograft copolymer with an alginate backbone, hetero-grafted by polymer pendant chains displaying different Lower Critical Solution Temperatures (LCSTs), combined with a pH-responsive Poly(2-vinyl pyridine)-b-poly(ethylene oxide) (P2VP-b-PEO) diblock copolymer forming micellar nanoparticles, was investigated in aqueous media at various pH. Due to its thermoresponsive side chains, the copolymer forms hydrogels with thermo–induced sol–gel transition, above a critical temperature, Tgel (thermo–thickening). However, by lowering pH of the medium in acidic regime, a remarkable increase of the elasticity of the formulation was observed. This effect was more pronounced in low temperatures (below Tgel) suggesting secondary physical crosslinking, which induces significant changes in the hydrogel thermoresponsiveness, transforming the sol–gel transition to soft gel–strong gel. Moreover, the onset of thermothickening shifted to lower temperatures followed by broadening of the transition zone, implying intermolecular interactions between the uncharged alginate backbone with the PNIPAM side chains, likely through H–bonding. The shear–thinning behavior of the soft gel in low temperatures provides injectability, which allows 3D–printing potential applications. Furthermore, the heterograft copolymer/nanoparticles composite hydrogel, encapsulating a model hydrophobic drug in the hydrophobic cores of the nanoparticles, was evaluated as pH-responsive drug delivery system. The presented tunable drug delivery system might be useful for biomedical potential applications.