Biomechanical assessment of a new adhesive bone cement for otologic surgery.

The adhesion of metallic prostheses to bone is a major problem in otologic surgery. Conventional bone cements lack significant adhesive strength, which predisposes the cemented prosthesis to loosening. The advent of surgically implantable hearing devices is one example where an adhesive cement to secure metal to bone would be useful. The biomechanical properties of a new cement, 4-META/MMA-TBB opaque resin, were evaluated in an animal model. The cement is composed of 4-methacryloyloxyethyl trimellitate anhydride (4-META) and methyl methacrylate (MMA) as monomers and tri-n-butyl borane (TBB) as an initiator. Titanium disks were cemented to the tibias of rabbits, which were sacrificed at 0 and 90 days. Tensile and shear bond strengths between bone and metal were tested at both times. The mean baseline tensile and shear bond strengths were 8.92 MPa and 11.96 MPa, respectively. Adhesive failure occurred at the bone-cement interface. The decrease in bond strength at 90 days was minimal. Thus, 4-META/MMA-TBB cement is a promising new metal-to-bone adhesive that may be useful for the surgical fixation of metallic prostheses in otologic surgery.