Methods: Zero (C), 15%, or 30% of IBMA was added to photoinitiated DHDPE/DHDPTE (50%/50%) and a GTE (bis-GMA—bis-EMA—TEGDMA) control. Rectangular beams 2X2X30 mm were cured in an LED cure box (Proto-tech) for 2 minutes. Transverse strengths and moduli were then measured using the MTS-Instron 1125 universal testing machine. Furthermore, the shrinkage of each blend was measured with the ACUVOL after a 40 second light cure with a standard quartz-halogen curing lamp (Coltene).
Results: The resultant volumetric cure shrinkages are (mean ± s.d.): DHDPE/DHDPTE with zero (5.2 ± .2), 15% (6.1 ± .2), and 30% IBMA (6.9 ± .2). GTE with zero (9.7 ± .5), 15% (9.9 ± .6), and 30% IBMA (9.0 ± .3). By two-way ANOVA, the monomers were very highly significantly different, p < 0.00005. Shrinkage increased significantly with increasing IBMA for the experimental monomers. Strengths and moduli were significantly higher for the GTE control resin compared to the experimental groups.
Conclusions: The DHDPE/DHDPTE blends showed significantly lower shrinkage compared to similar blends of the GTE control, but the addition of IBMA did not statistically improve the transverse strengths and moduli of DHDPE/DHDPTE. The DHDPE/DHDPTE comonomer blends need further evaluation, but show promise due to their low shrinkage values.
Supported by NIH-NIDCR P01DE11688 and NIDCR T32-DE14318 (Co*Star)