Alternative radiopacifiers for polymethyl methacrylate bone cements: Silane-treated anatase titanium dioxide and yttria-stabilised zirconium dioxide

Abstract

Poly (methyl methacrylate) (PMMA) bone cement is widely used for anchoring joint arthroplasties. In cement brands approved for these procedures, micron-sized particles (usually barium sulphate, BaSO4) act as the radiopacifier. It has been postulated that these particles act as sites for crack initiation and subsequently cement fatigue. This study investigated whether alternative radiopacifiers, anatase titanium dioxide (TiO2) and yttria-stabilised zirconium dioxide (ZrO2), could improve the in vitro mechanical, fatigue crack propagation and biological properties of polymethyl methacrylate (PMMA) bone cement and whether their coating with a silane could further enhance cement performance. Cement samples containing 0, 5, 10, 15, 20 and 25%w/w TiO2 or ZrO2 and 10%w/w silane-treated TiO2 or ZrO2 were prepared and characterised in vitro in terms of radiopacity, compressive and bending strength, bending modulus, fatigue crack propagation, hydroxyapatite forming ability and MC3T3-E1 cell attachment and viability. Cement samples with greater than 10%w/w TiO2 and ZrO2 had a similar radiopacity to the control 10%w/w BaSO4 cement and commercial products. The addition of TiO2 and ZrO2 to bone cement reduced the bending strength and fracture toughness and increased fatigue crack propagation due to the formation of agglomerations and voids. Silane treating TiO2 reversed this effect, enhancing the dispersion and adhesion of particles to the PMMA matrix and resulted in improved mechanical properties and fatigue crack propagation resistance. Silane-treated TiO2 cements had increased nucleation of hydroxyapatite and MC3T3-E1 cell attachment in vitro, without significantly compromising cell viability. This research has demonstrated that 10%w/w silane-treated anatase TiO2 is a promising alternative radiopacifier for PMMA bone cement offering additional benefits over conventional BaSO4 radiopacifiers.

Effect of using nano-particles of magnesium oxide and titanium dioxide to enhance physical and mechanical properties of hip joint bone cement

“…3 h is prepared to produce rectangular bending test specimens with dimensions 75 mm, 10 mm, and 3.3 mm as clarified in Fig. 3 i,j 11 . Specimens were tested in AUTOMAX MULTITEST Computerized Control machine.…”

“…The previous research illustrated the effect of adding Titanium Dioxide (TiO 2 ) and Magnesium Oxide (MgO) in improving bone cement mechanical properties 9 , 10 . The advantages of adding TiO 2 particles to bone cement include higher elasticity, lower cytotoxicity, good cytocompatibility with osteoblasts, improved radiopacity, and improved mechanical qualities (compression and bending strengths) 11 , 12 . Also, adding MgO particles directly improves osteoblast adhesion 13 , 14 , antibacterial effect, cytocompatibility with osteoblasts, and potential for joint repair and fixation 15 .…”

Effect of using Nano-particles of Magnesium Oxide and Titanium Dioxide to Enhance Properties of Hip Joint Bone Cement

“…The radiopaque used is ZrO 2 particles, commonly found in 2-micron size as shown in Fig. 2(i), it has direct effect in radiopaque that allows tracking and assessment of bone cement after xing arti cial joints, by focusing the view with X-ray scan [11] [9].…”

Parameters controlling octadecyl phosphonic acid self-assembled monolayers on titanium dioxide for anti-fouling biomedical applications

“…Thiols give uniform and hydrolytically stable films on surfaces however, the major drawback of thiol-based SAMs is a susceptibility to oxidisation that compromise their long-term stability [7]. Organosilane SAMs form by hydrolysis of the labile groups, condensation of oligomers and hydrogen bonding with surface hydroxyl groups resulting in the formation of covalent bonds during curing [8]. The amount of water present in solution during functionalization is a key factor influencing the quality of the monolayer in order to avoid premature polymerization of the silane and multilayer adsorption [9].…”

“…Phosphonic acid SAMs produce a more robust film than the previously discussed compounds due to their greater hydrolytic stability. Octadecylphosphonic acid (ODPA) SAMs in particular, have been used to modify surfaces of different oxides, such as titanium [10], copper [11], aluminium [12,13], cobalt-chromium alloy [14] and have demonstrated additional biomedical benefits in encouraging osseointegration and preventing bacterial colonisation [8,10].…”