IADR Abstract Archives
Effect of Shade on Curing Characteristics of a Composite Resin
Objectives: This study investigated the effect of shade on curing characteristics of a conventional composite by Vickers microhardness (VH) and residual radiant energy (ER) measured at the bottom surface of the specimen during curing.
Methods: 1- and 2 mm thick Delrin washers (OD:19mm; ID:6.4mm) were used to fill with Filtek Supreme Ultimate (3M/ESPE, Minneapolis, MN, USA) of shade A1E, A3E, A1B, A6B, AD1 or C4D and cured with Radii Plus (1200mW/cm2; SDI, Bayswater, Victoria, Australia). ER was recorded with MARC (BlueLight Analytics, Halifax, Canada). 2 mm washers were used to prepare A1E, AE3 and A1B specimens. A6B, A1D and C4D, which absorbed more light, were prepared with 1 mm washers. Each specimen was cured for duration from 2 to 24s (nine durations for each shade). VH (mean of 5 indentations) of bottom surface was measured 7d after curing. Duplicate specimens were measured for each shade and curing time.
Results: Non-linear regression (SAS 9.4) of VH vs (ER) by VH=α[1-exp(-ER/β)] was used to determine α, maximum hardness (VHmax), and β, rate parameter (Table). The table also includes calculated time elapse and ER at 95% of maximum hardness (ER,95). Time elapse was calculated based on the linearity of ER over curing time. ANOVA and Tukey analyses show for VHmax there is no statistical difference between EA1 and EA3 (p=0.9571), and among A1B, A6B, A1D and C4D (p=0.8708); there is no difference of rate parameter among all shades.
Conclusions: The VHmax is dependent on the opacity but not the rate parameter
The Authors thank 3M Espe for donating the composite materials
Methods: 1- and 2 mm thick Delrin washers (OD:19mm; ID:6.4mm) were used to fill with Filtek Supreme Ultimate (3M/ESPE, Minneapolis, MN, USA) of shade A1E, A3E, A1B, A6B, AD1 or C4D and cured with Radii Plus (1200mW/cm2; SDI, Bayswater, Victoria, Australia). ER was recorded with MARC (BlueLight Analytics, Halifax, Canada). 2 mm washers were used to prepare A1E, AE3 and A1B specimens. A6B, A1D and C4D, which absorbed more light, were prepared with 1 mm washers. Each specimen was cured for duration from 2 to 24s (nine durations for each shade). VH (mean of 5 indentations) of bottom surface was measured 7d after curing. Duplicate specimens were measured for each shade and curing time.
Results: Non-linear regression (SAS 9.4) of VH vs (ER) by VH=α[1-exp(-ER/β)] was used to determine α, maximum hardness (VHmax), and β, rate parameter (Table). The table also includes calculated time elapse and ER at 95% of maximum hardness (ER,95). Time elapse was calculated based on the linearity of ER over curing time. ANOVA and Tukey analyses show for VHmax there is no statistical difference between EA1 and EA3 (p=0.9571), and among A1B, A6B, A1D and C4D (p=0.8708); there is no difference of rate parameter among all shades.
Conclusions: The VHmax is dependent on the opacity but not the rate parameter
The Authors thank 3M Espe for donating the composite materials