Assessment of Resorbable Bioactive Material for Grafting of Critical-size Cancellous Defects

Abstract

Bioactive glasses form a surface apatite layer in uivo that enhances the formation and attachment of bone. Sol-gel Bioglass graft material provides greater nanoscale porosity than bioactive glass (on the order of 50-200 A), greater particle surface area, and improved resorbability. while maintaining bioactivity. This study histologically and biomechanically evaluated, in a rabbit model. bone formed within critical-sized distal femoral cancellous bone defects filled with 4SS5 Bioglass particulates, 77s sol-gel Bioglass. or 58s sol-gel Bioglass and compared the bone in these defects with normal. intact, untreated cancellous bone and with unfilled defects at 4, 8. and 12 weeks. All grafted defects had more bone within the area than did unfilled controls (p < 0.05). The percentage of bone within the defect was significantly greater for the 4585 material than for the 58s or 77s material at 4 and 8 weeks (p < 0.05), yet by 12 weeks equivalent amounts of bone were observed for all materials. By 12 weeks, all grafted defects were equivalent to the normal untreated bone. The resorption of 77s and 58s particles was significantly greater than that of 4585 particles (p < 0.05). Mechanically, the grafted defects had compressive stiffness equivalent to that of normal bone at 4 and 8 weeks. At 12 weeks, 45SS-grafted defects had significantly greater stiffness (p < 0.05). At 8 and 12 weeks, all grafted defects had significantly greater stiffness than unfilled control defects (p < 0.05). In general, the 45S5filled defects exhibited greater early bone ingrowth than did those filled with 585 or 77s. However, by 12 weeks, the bone ingrowth in each defect was equivalent to each other and to normal bone. The 58s and 77s materials resorbed faster than the 45S5 materials. Mechanically, the compressive characteristics of all grafted defects were equivalent or greater than those of normal bone at all time points.

Preconditioned 70S30C bioactive glass foams promote osteogenesis in vivo

“…Replacement of the marrow cavity with osseous tissue might prove detrimental to the functioning of the newly formed bone due to restriction of the vascular supply. No quantifiable dissolution of the NovaBone was observed, which was in line with previous studies conducted in the femoral condyle of rabbits with 45S5 Bioglass (under the trade names of NovaBone or Perioglas) [16,37] for 12 weeks and 1 year respectively.…”

“…70S30C scaffolds induced extracellular matrix formation by differentiating murine osteoblasts, as well as promotion of C7 macrophage differentiation into osteoclasts and subsequent resorption pit formation, indicating the potential for remodelling of the scaffold as bone regenerates [36]. However in vivo studies have been limited to sol-gel particles [37], balls [38] or dense monoliths [16]. An in vivo study by Wang and co-workers on 70S30C BG reported soft tissue infiltration within the porous scaffold in a rabbit subcutaneous model; however, the research findings were based on poor histological evidence and lacked reliability [39].…”

Reprint of: Review of bioactive glass: From Hench to hybrids

“…The Bioglass 45S5 was also seen to degrade more rapidly than HA and the degradation was attributed to solution-mediated dissolution (rather than cellular/enzyme action) [80][81][82][83]. These studies indicate that Bioglass 45S5 regenerates bone better than the more commercially successful bioceramics.…”

“…Wheeler et al [83] compared Bioglass 45S5 with sol-gel glass particles of the 77S and 58S in the Oonishi model. Up until 8 weeks after implantation, bone defects filled with Bioglass 45S5 contained more bone than those filled with 77S or 58S, but within 12 weeks the amounts were equivalent.…”

Backscattered electron microscopy evidences tight apposition between bone and bioactive glass coating in vivo

“…These materials have similar osteoconductive properties to melt-derived glasses, but have an improved degradability [9]. Sol-gel processing is an ideal route to achieve compositional and structural control.…”