IADR Abstract Archives
Hexagonal Boron Nitride UDMA Resin Composites
Objectives: To evaluate the potential of Hexagonal Boron Nitride as a reinforcing filler for light curable UDMA resin composites.
Methods: Experimental resin composite formulated by incorporating 40 wt% hydroxyapatite into a UDMA monomer matrix with a photo-initiator system of CQ and DMAEM was used as control for the present study. Four hexagonal Boron Nitride (hBN) resin composites were fabricated by introducing 0.25 and 0.5 wt% of two hBN with difference morphology into the control. Cylindrical specimens (5 mm x 1/2 mm) were light cured and the real time transmitted irradiance at the bottom specimen surface was recorded using a calibrated spectrometer (MARC Resin Calibrator). The degree of conversion immediate and 7 d after cured (DC0 and DC7d), post-irradiance hardness (VHN0 and VHN7d) and 7 d post-cured flexural strength were measured by a FTIR spectroscopy, a Vickers indenter and a universal testing machine respectively (n=5). Difference between the results was analysed using one way ANOVA (p<0.05) followed by Tukey`s post hoc test.
Results: The presence of hBN did not change the overall shape of the irradiation curve, but resulted in a reduction in the maximum transmitted irradiance (Imax) at the bottom sample surface compared with control. Sample thickness in contract had a dramatic influence on Imax. The addition of hBN did not significantly change DC for the 1 mm specimens; however, 0.5 wt% h-BN has a detrimental influence on DC for the 2 mm specimens. Post-irradiance hardness increased after 7 d, but no significant difference was noticed between groups. The addition of hBN led to a significant increase in flexural strength compared with the control group.
Conclusions: Small amount of hBN did not change the curability of experimental UDMA resin composite but led to increased flexural strengths indicating that hBN has the potentials as a reinforcing filler for dental resin composites.
Methods: Experimental resin composite formulated by incorporating 40 wt% hydroxyapatite into a UDMA monomer matrix with a photo-initiator system of CQ and DMAEM was used as control for the present study. Four hexagonal Boron Nitride (hBN) resin composites were fabricated by introducing 0.25 and 0.5 wt% of two hBN with difference morphology into the control. Cylindrical specimens (5 mm x 1/2 mm) were light cured and the real time transmitted irradiance at the bottom specimen surface was recorded using a calibrated spectrometer (MARC Resin Calibrator). The degree of conversion immediate and 7 d after cured (DC0 and DC7d), post-irradiance hardness (VHN0 and VHN7d) and 7 d post-cured flexural strength were measured by a FTIR spectroscopy, a Vickers indenter and a universal testing machine respectively (n=5). Difference between the results was analysed using one way ANOVA (p<0.05) followed by Tukey`s post hoc test.
Results: The presence of hBN did not change the overall shape of the irradiation curve, but resulted in a reduction in the maximum transmitted irradiance (Imax) at the bottom sample surface compared with control. Sample thickness in contract had a dramatic influence on Imax. The addition of hBN did not significantly change DC for the 1 mm specimens; however, 0.5 wt% h-BN has a detrimental influence on DC for the 2 mm specimens. Post-irradiance hardness increased after 7 d, but no significant difference was noticed between groups. The addition of hBN led to a significant increase in flexural strength compared with the control group.
Conclusions: Small amount of hBN did not change the curability of experimental UDMA resin composite but led to increased flexural strengths indicating that hBN has the potentials as a reinforcing filler for dental resin composites.