hrvatski

Rapid (3 s) high-intensity light-curing: Polymerization kinetics

Introduction: This study aimed to investigate polymerization kinetics of resin composites light- cured using a rapid high-intensity curing protocol. Materials and methods: Two composites specifically designed for high-intensity light- curing and four reference composites were investigated. Composite specimens were prepared using Teflon molds (diameter = 6 mm, height = 2 mm) on top of a diamond ATR crystal and light- cured using the following protocols: (I) 3, 000 mW/cm2 for 3 s ; (II) 2, 000 mW/cm2 for 5 s ; and (III) 1, 000 mW/cm2 for 10 s. Real-time degree of conversion (DC) changes were continuously measured over 5 min after the initiation of light-curing using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The data collection rate of 2 spectra/s enabled the evaluation of kinetic parameters. First derivatives of time-dependent DC curves were calculated to characterize the reaction rate. Results: DC at the end of the 5-min observation period amounted to 40.0–67.2%. Out of all kinetic parameters, maximum reaction rate (5.6–25.7%/s) was the most affected by different curing protocols. Highly significant differences in maximum reaction rates caused by variable radiant exitances were identified in five out of six investigated composites. Time of the maximum reaction rate (1.7–3.3 s) was the least discriminative parameter, mostly showing statistically similar values among the curing protocols. Partial eta-squared statistics identified that material type was more influential for all kinetic parameters compared to curing protocols. Significant interactions between material type and curing protocol were identified, indicating material-dependent responses to high- intensity light-curing. Conclusions: High- intensity light-curing significantly increased the polymerization rate, with possible implications on the development of polymerization shrinkage stress.

dental materials ; curing lights, dental ; composite resins ; polymerization

nije evidentirano

engleski

Rapid (3 s) high-intensity light-curing: Polymerization kinetics

Introduction: This study aimed to investigate polymerization kinetics of resin composites light- cured using a rapid high-intensity curing protocol. Materials and methods: Two composites specifically designed for high-intensity light- curing and four reference composites were investigated. Composite specimens were prepared using Teflon molds (diameter = 6 mm, height = 2 mm) on top of a diamond ATR crystal and light- cured using the following protocols: (I) 3, 000 mW/cm2 for 3 s ; (II) 2, 000 mW/cm2 for 5 s ; and (III) 1, 000 mW/cm2 for 10 s. Real-time degree of conversion (DC) changes were continuously measured over 5 min after the initiation of light-curing using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The data collection rate of 2 spectra/s enabled the evaluation of kinetic parameters. First derivatives of time-dependent DC curves were calculated to characterize the reaction rate. Results: DC at the end of the 5-min observation period amounted to 40.0–67.2%. Out of all kinetic parameters, maximum reaction rate (5.6–25.7%/s) was the most affected by different curing protocols. Highly significant differences in maximum reaction rates caused by variable radiant exitances were identified in five out of six investigated composites. Time of the maximum reaction rate (1.7–3.3 s) was the least discriminative parameter, mostly showing statistically similar values among the curing protocols. Partial eta-squared statistics identified that material type was more influential for all kinetic parameters compared to curing protocols. Significant interactions between material type and curing protocol were identified, indicating material-dependent responses to high- intensity light-curing. Conclusions: High- intensity light-curing significantly increased the polymerization rate, with possible implications on the development of polymerization shrinkage stress.

dental materials ; curing lights, dental ; composite resins ; polymerization

nije evidentirano