Bone-bonding behavior of alumina bead composite

Abstract

Previously we developed an alumina bead composite (ABC) consisting of alumina bead powder (AL-P) and bisphenol-alpha-glycidyl methacrylate (Bis-GMA)-based resin and reported its excellent osteoconductivity in rat tibiae. In the present study, are evaluated histologically and mechanically the effect of alumina crystallinity on the osteoconductivity and bone-bonding strength of the composite. AL-P was manufactured by fusing crushed alpha-alumina powder and quenching it. The AL-P was composed mainly of amorphous and delta-crystal phases of alumina. Its average particle size was 3.5 microm, and it took a spherical form. Another composite (alpha ALC), filled with pure alpha-alumina powder (alpha AL-P), was used as a referential material. The proportion of powder added to each composite was 70% w/w. Mechanical testing of ABC and alpha ALC indicated that they would be strong enough for use under weight-bearing conditions. The affinity indices for ABC, determined using male Wistar rat tibiae, were significantly higher than those for alpha ALC (p < 0.0001) up to 8 weeks. Composite plates (15 x 10 x 2 mm) that had an uncured surface layer on one side were made in situ in a rectangular mold. One of the plates was implanted into the proximal metaphysis of the tibia of a male Japanese white rabbit, and the failure load was measured by a detaching test 10 weeks after implantation. The failure loads for ABC on its uncured surface [1.91+/-1.23 kgf (n = 8)] were significantly higher than those for alpha ALC on its uncured surface [0.35+/-0.33 kgf (n = 8); (p < 0.0001)], and they also were significantly higher than those for ABC on the other (cured surface) side (p < 0.0001). Histological examinations using rabbit tibiae revealed bone ingrowth into the composite only on the uncured surface of ABC. This study revealed that the amorphous phase of alumina and formation of an uncured surface layer are needed for the osteoconductive and bone-bonding ability of ABC. ABC shows promise as a basis for the development of a highly osteoconductive and mechanically strong biomaterial.

Bioactive bone cement: Effect of silane treatment on mechanical properties and osteoconductivity

“…4,6,7,[10][11][12][13]16,17 To calculate the affinity index from a SEM photograph, we divided the length of bone in direct contact with the cement surface without any intervening soft tissue by the total length of the cement surface, and this value was multiplied by 100. 4,6,7,[10][11][12][13]17 The length of bone in direct contact with the cement surface and the total length of the cement surface were measured with an integrated image analyzer (Tectron, Kyoto, Japan). 4,6,7,[10][11][12][13]17 When the total length of the cement surface was measured, the area outside the tibia (i.e., the area of the cortical bone defect) was excluded because the cement was in contact with soft tissue in that region, and our intention was to examine the reaction of the cement within the bone.…”

“…The quantities of the silane coupling agent used were 0 (control), 0.1, 0.2, 0.5, and 1.0% (w/w) of the glass beads, and the cements were designated GBCs0, GBCs0.1, GBCs0.2, GBCs0.5, and GBCs1.0, respectively. The purpose of this study was to measure the mechanical properties and evaluate the osteoconductivity of the cements in terms of affinity indices with rat tibiae, 4,6,7,[10][11][12][13]16,17 to examine the bone-cement interface histologically, and to determine the optimum amount of silane coupling agent for the treatment of the beads.…”

Whisker-reinforced bioactive composites containing calcium phosphate cement fillers: Effects of filler ratio and surface treatments on mechanical properties

“…35,36,38 First, when the resin composite paste is implanted in vivo and polymerized in situ, the hardened composite would contain an uncured surface, because the oxygen present in blood inhibits radical polymerization reactions. 36,38 This has been shown to expose the bioactive fillers at the implant surfaces and thus induce bone bonding. 36,38 Second, the Bis-GMA-based composites can be used as prefabricated implants with abraded surfaces.…”

“…36,38 This has been shown to expose the bioactive fillers at the implant surfaces and thus induce bone bonding. 36,38 Second, the Bis-GMA-based composites can be used as prefabricated implants with abraded surfaces. The abrasion has been demonstrated to expose the bioactive fillers at the implant surfaces with increased bone-bonding ability.…”

“…[26][27][28][29][30][31] When bioactive fillers were added, Bis-GMA-based composites were rendered bioactive and were investigated for bone repair applications. [32][33][34][35][36][37][38] Bioactive fillers used in Bis-GMA-based composites included hydroxyapatite, bioactive glass and glassceramics, and calcium phosphates. [32][33][34][35][36][37][38] Previous studies have examined the effects of bioactive filler content 37 and bioactive filler/silica glass ratio 34 on Bis-GMA-based composite properties.…”