Objectives: Aim of this study was to compare the light stability of two chemically different curing composites at different illuminations of a dental operatory lamp.
Methods: The radically curing Tetric EvoCeram (EVO, Ivoclar-Vivadent) and the cationic ring opening Filtek Silorane (SIL, 3M ESPE) were exposed at four illuminations (4000 lux, 8000 lux, 14000 lux, and 20000 lux) to a dental operatory lamp. The light stability was determined according the procedure of the EN ISO 4049 except the variation of different illuminations. (EN ISO 4049 only considers 8000 lux).
Results: The following table shows the light stability of Tetric EvoCeram and Filtek Silorane in seconds:
Material | Manufacturer | t@4000 lx | t@8000 lx | t@14000 lx | t@20000 lx |
Tetric EvoCeram | Ivoclar-Vivadent | 210 | 110 | 60 | 50 |
Filtek Silorane | 3M ESPE | 720 | 360 | 180 | 150
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A reciprocal function for t[EVO]=1,07*10^(-6)/Lux[lx] and t[SIL]= 3,53*10^(-6)/Lux[lx] was found. The statistical correlation factor calculates to R²= 0,971 (SIL) and R²=0,974 (EVO). The quotient of the function yields to a higher light stability of Silorane of a factor of 330%.
Conclusion: Filtek Silorane exhibits at every illumination a higher light stability than Tetric EvoCeram. In both cases a decrease of the light stability with increasing illumination was observed. For both materials a reciprocal correlation of 1/time~illumination was found.