New Monomers as Alternatives to Bis-GMA

Objectives: In this study, the properties of two new dimethacrylate polyester oligomers, PEM659 and PEM665, were evaluated, as monomers, homopolymers and copolymers, and compared with the properties of commonly used Bis-GMA.

Methods: The oligomers were evaluated as homopolymers or in combination with TEGDMA (Triethyleneglycol dimethacrylate) or HDDMA (1,6-hexanediol dimethacrylate) as diluent monomers. Photopolymerization reactivity and conversion were investigated with near-infrared spectroscopy. Volumetric shrinkage studies were carried out using a linometer as well as a pycnometer. Shrinkage stress was determined using tensometer. Flexural strength, water sorption and solubility were measured according to the International Standard ISO 4049 and ADA specification 27. Modulus was determined in the same test as flexural strength. For comparison, all tests were also performed on control samples of Bis-GMA and Bis-GMA/ TEGDMA and Bis-GMA/ HDDMA.

Results: The new oligomers produced higher degrees of conversion, lower polymerization shrinkage and lower water sorption and solubility than Bis-GMA based materials. Mechanical properties were comparable with those of Bis-GMA.

Conclusions: On the basis of the properties demonstrated by the new monomers and their homopolymers, these new materials appear well suited for dental applications.

Septodont thanks Designer Molecules Inc. for the kind donation of materials.