Bone-bonding behavior of alumina bead composite

Area of Science:

• Biomaterials Science
• Orthopedic Research
• Materials Engineering

Background:

• Alumina bead composite (ABC) with bisphenol-alpha-glycidyl methacrylate (Bis-GMA) resin demonstrated excellent osteoconductivity in previous studies.
• The effect of alumina crystallinity on the osteoconductivity and bone-bonding strength of ABC requires further investigation.

Purpose of the Study:

• To evaluate the impact of alumina crystallinity on the osteoconductivity and bone-bonding strength of alumina bead composite (ABC).
• To compare the performance of ABC with a composite made from pure alpha-alumina powder (alpha ALC).

Main Methods:

• Alumina bead powder (AL-P), composed of amorphous and delta-crystal alumina phases, was prepared and incorporated into a Bis-GMA resin.
• Mechanical testing was performed on ABC and alpha ALC composites.
• In vivo studies involved implantation in rat and rabbit tibiae to assess osteoconductivity (affinity index) and bone-bonding strength (failure load).

Main Results:

• ABC exhibited significantly higher affinity indices in rat tibiae compared to alpha ALC up to 8 weeks (p < 0.0001).
• Failure loads for ABC on its uncured surface were significantly higher than for alpha ALC on its uncured surface and for ABC on its cured surface in rabbit tibiae (p < 0.0001).
• Histological examination revealed bone ingrowth into ABC exclusively on the uncured surface.

Conclusions:

• The amorphous phase of alumina and the presence of an uncured surface layer are essential for the osteoconductive and bone-bonding capabilities of ABC.
• ABC demonstrates significant potential as a biomaterial for applications requiring high osteoconductivity and mechanical robustness.