Purpose: To investigate the effect of light-emitting diode (LED) light curing unit (LCU) and quartz-tungsten (QTH) LCU on the polymerization-shrinkage of different resin composites.
Methods: Three composites Z100, Z250, AP-X were irradiated by QTH LCU and LED LCU. Polymerization-shrinkage of 50s and 400s after the composites curing were measured by 3D-profile measuring apparatus by phase-shifted projected grating.The polymerization-shrinkage of LED and QTH curing composites were analysed by SPSS12.0 software package of one-way ANOVA.
Results: At 50s curing and 400s curing period, the polymerization- shrinkage of Z100, Z250 resin was different by QTH LCU and LED LCU curing, the polymerization-shrinkage by LED LCU curing was less than that by QTH LCU (P < 0.05); the polymerization-shrinkage of AP-X was not statistically different by QTH LCU and LED LCU curing (P > 0.05). CONCLUSUINS: The polymerization-shrinkage of Z100,Z250 resin is statistically less cured by LED LCU than QTH; the polymerization-shrinkage of AP-X resin is not statistically different cured by QTH LCU and LED LCU. Supported by Research Fund of Science and Technology Commission of Shanghai Municipality (08DZ2271100).