BIOMECHANICAL ASSESSMENT OF A NEW ADHESIVE BONE-CEMENT FOR OTOLOGIC SURGERY

The adhesion of metallic prostheses to bone is a major problem in otol ogic surgery. Conventional bone cements lack significant adhesive stre ngth, which predisposes the cemented prosthesis to loosening. The adve nt of surgically implantable hearing devices is one example where an a dhesive cement to secure metal to bone would be useful. The biomechani cal properties of a new cement, 4-META/MMA-TBB opaque resin, were eval uated in an animal model. The cement is composed of 4-methacryloyloxye thyl 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 streng ths were 8.92 MPa and 11.96 MPa, respectively. Adhesive failure occurr ed at the bone-cement interface. The decrease in bond strength at 90 d ays 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 metal lic prostheses in otologic surgery.