Self-curing acrylic cements formulated with Bis-GMA

SCHROEDER, WALTER F.; VALLO, CLAUDIA I.

Foz do Iguaçu, Brazil

Congreso; 3rd Brazil - MRS Meeting; 2004

Sociedade Brasileira de Pesquisa em Materiais (SBPMat)

Experimental cement formulations were prepared by replacing part of the methylmethacrylate (MMA) liquid phase of a conventional surgical cement by an equivalent weight of 2,2-bis [4(2-hydroxy-3-methacryloxypropoxy) phenyl] propane (Bis-GMA), which is the reaction product of Bisphenol A and methacrylic acid. It was found that up to 50 weight percent of the MMA could be replaced by Bis-GMA without reductions in flow characteristics of the precured polymers. Cements containing 20, 30, 40 and 50 weight percent of Bis-GMA in the liquid component were prepared. Over this range of Bis-GMA weight percent, it was found that, relative to the unmodified cement, the volumetric shrinkage (DV), the peak temperature reached during the polymerization reaction (Tp), and the flexural strength (obtained in three-point bending tests) were each significantly reduced, while there were no significant effects on any of the other properties determined, namely, degree of conversion of the monomer during the polymerization reaction, the glass transition temperature, the compressive strength, and the flexural modulus. The increase in the crosslinking density with increasing amount of Bis-GMA renders the polymer matrix more brittle. This feature was considered responsible for the reduced flexural strength. However, the drops in DV and Tp indicate that cements whose liquid monomers are modified using Bis-GMA hold promise for use in anchoring total joint replacements.