Biologic significance of surface microroughing in bone incorporation of porous bioactive glass implants

Abstract

A novel chemical etching method was recently developed to create a controlled microrough surface on porous bioactive glass implants. Our earlier in vitro studies showed enhanced attachment of osteoblast-like MG63 cells on a microrough bioactive glass surface. The purpose of our current study was to confirm the in vivo significance of surface microroughening for bone bonding of bioactive glass. Porous bioactive glass cones made of sintered microspheres were surgically implanted in the anterior cortex of rabbit femurs. Peripheral quantitative computed tomography (pQCT), biomechanical push-out testing, histomorphometry, and electron microscopy (BEI-SEM) were used to analyze bone ingrowth and osseointegration at 7, 10, 14, 28, 56, and 84 days after implantation. The results showed that microroughening of the bioactive glass surface significantly enhanced the bone-bonding response of the biomaterial. The positive response was seen in one of the three bioactive glass compositions studied. The affinity index of new bone on the glass surface was significantly (p = 0.02) increased with a trend (p = 0.10) toward improved mechanical incorporation. New bone formation was dependent on the glass composition, and it was found to occur not only through the mechanism of bone ingrowth but also based on in situ osteogenesis within implant interstices. Based on these results, the procedure of microroughening could enhance the osteopromotive properties of certain bioactive glass compositions.

Bioactive glass scaffolds for bone tissue engineering: state of the art and future perspectives

“…The ability of bioactive glass scaffolds to support cell proliferation and function in vitro and tissue ingrowth in vivo has been shown in numerous studies [90, 106, 139–142] [97, 115]. Fu et al [90] showed that 13–93 bioactive glass scaffolds prepared using a polymer foam replication method supported the attachment and proliferation of MC3T3-E1 pre-osteoblastic cells both on the surface and within the interior pores of the scaffold (Figs.…”

Factors affecting crystallization of bioactive glasses

“…5 The bioactivity of these sintered bodies has been tested in vivo. 6 The increased workability often means also changes in the bioactivity of the glass leading to only medium or low bioactivity. 7 Although the understanding of the influence of different components on both the bioactivity and the working properties has increased, still the most clinically used bioactive glasses are plates, granules and powdered glass, i.e.…”

Structuring of bioactive glass surfaces at the micrometer scale by direct casting intended to influence cell response

“…It is known that different cell types react to patterned surfaces: Roughened biomaterial surfaces in the micrometer range can enhance cell adhesion in vitro [37,38] and bone-to-implant contact in vivo [3]. Itälä et al have shown that microroughening of porous bioactive glass surfaces enhance the biological activity of certain bioactive glass compositions [22]. In this study first live/dead experiments on structured bioactive glasses have shown that almost all cells appear green, displaying alive cells.…”

“…Following in vivo experiments even showed a higher amount of incorporated new bone in comparison to smooth implants [22]. Porous structures were realized by lithography-based additive manufacturing as well, creating crystallized bioglass samples [23].…”