Exothermal Characteristics and Release of Residual Monomers from Fiber-reinforced Oligomer-modified Acrylic Bone Cement

Abstract

The aim of this study is to determine the peak temperature of polymerization, the setting time and the release of residual monomers of a modified acrylic bone cement. Palacos Õ R, a commercial bone cement, is used as the main component. The cement is modified by adding short glass fibers and resorbable oligomer fillers, and an additional cross-linking monomer. The test specimens are classified according to the composition of the bone cement matrix (i.e., oligomer-filler, glass-fiber reinforcement, and/or cross-linking monomer). The exothermal characteristics during autopolymerization are analyzed using a transducer connected with a computer. The quantities of residual monomers were analyzed from different test groups using high performance liquid chromatography (HPLC). The ÁT value for the oligomer filler and the glass-fiber-containing acrylic bone cement is lower than that for the unmodified bone cement (2.1 AE 0.8 C vs. 23.5 AE 4.2 C). The addition of a cross-linking monomer, EGDMA, shortens the setting time of the autopolymerization of the unmodified bone cement (7.1 AE 0.9 min vs. 3.3 AE 0.3 min).*Author to whom correspondence should be addressed. E-mail: mervi.puska@utu.fi The quantity of the residual monomers released is higher in the modified bone cement than that in the unmodified cement. The cement that contains glass fibers and oligomer fillers has a considerably lower exothermal peak, whereas the total quantity of residual monomers released is increased. JOURNAL OF BIOMATERIALS APPLICATIONS

Morphological and mechanical characterization of composite bone cement containing polymethylmethacrylate matrix functionalized with trimethoxysilyl and bioactive glass

“…In addition, the reinforcing effect on mechanical properties will be studied using hyperbranched monomers, such as bifunctional or dendritic acrylate monomers. In fact, the addition of bifunctional monomer, like ethylene glycol dimethacrylate (EGDMA), has shown to reduce the quantity of released monomers and increase the mechanical properties (Puska et al, 2005).…”

Physical and Mechanical Properties of PMMA Bone Cement Reinforced with Nano-sized Titania Fibers

“…The observed decrease in the polymerization exotherm can be attributed to: (1) a decreased concentration of BPO in the modified cements [2], and (2) a higher surface area from the nanofibers dissipating the heat of polymerization. For similar reasons, the dough time and setting time increased when the amount of filler was increased [43][44][45]. However, with a small loading of n-TiO 2 fibers (up to 1 wt%), this phenomenon did not play a significant role, reflecting the result that the polymerization exotherm and dough and setting time do not significantly change with the addition of 1 wt% n-TiO 2 fibers when compared with CMW Õ 1 at p ¼ 0.05.…”

“…When increasing the incorporation of n-TiO 2 fibers into the cement, the polymer-to-monomer ratio (P/M) in the cement mixture decreases, in part leading to the lower initial viscosity and longer setting times of the reinforced cements [45]. Hence, at 1 wt% loading, the n-TiO 2 Physical and Mechanical Properties of PMMA Bone Cement fibers does not influence the cements rheology; rather, the P/M ratio plays a vital role to elongate the t ons and t cure .…”

Thermal manifestations and nanoindentation of bone cements for orthopaedic surgery

“…New knowledge in the sphere of basic and applied research have formed preconditions and substantial possibilities in the case of conventional orthopaedic surgical operations, such as correction of uneven length and deformations of limbs, osteosynthesis, and particularly in possibilities of replacements of worn-out degenerative joints either on the developing, inflammatory, traumatogenic, metabolic grounds or in the postoperative states. A big disadvantage to these bone cements is that it heats up to quite a high temperature, [9][10][11][13][14][15][16][17], while setting, potentially 82.5 °C, and because of this, thermal necrosis of neighbouring tissue might occur. The successful replacement of the destroyed joint means improvement of mobility, pain relief and returning back to accomplishing every day activities for a p/c.…”

“…Number of patients suffering from degenerative joint diseases (osteoarthritis) has been continually increasing and due to its seriousness, therapeutic complications and frequent patient/client (p/c) individualization, the disease represents inherent and significant medical, economic and social issue. A careful balance of initiators and monomers [10] is needed to reduce the rate of polymerisation, and thus the heat generated. Many patients at working age re-enter into an employment relationship after successful surgery related to the total endoprosthesis.…”