Safety and efficacy of Mg-Dy membrane with poly-L-lactic acid coating for guided bone regeneration

The aim of this study was to evaluate safety and efficacy of a poly-L-lactic acid (PLLA)-coated magnesium (Mg)-Dysprosium (Dy) membrane in guided bone regeneration (GBR) using a rabbit calvarium model. The microstructure of the Mg-Dy membrane surface and thickness of the PLLA coating were examined. In vitro degradation and cytotoxicity test was conducted. The in vivo study used 24 white male rabbits with two 8 mm-diameter defects created on the calvaria; 12 defects were randomly assigned per group: (1) Negative control, (2) positive control, (3) uncoated Mg, and (4) PLLA-coated Mg group. Specimens were harvested at 4, 8, and 12 weeks postoperatively for radiological, histological, and histomorphometric analyses. The PLLA-coated Mg-Dy membrane showed a low degree of degradation, indicating that the coating exerted a protective effect. In the cytotoxicity test, no deformed or degenerated cells were observed. In the in vivo study, radiographic and histomorphometric analyses indicated favorable new bone formation and maintenance of the graft material for PLLA-coated Mg group. PLLA-coated Mg group, compared to the uncoated counterpart, restored the bony contour more completely, without inducing significant inflammatory response. Our results support the safety and efficacy of PLLA-coated Mg-Dy membranes for GBR both in vitro and in vivo.