engleski

Effectiveness of blue LED based units with different curing modes

Objectives: Curing mode, i.e. light intensity, is one of the main parameters that determine degree of conversion (DC) of light activated materials. The aim of this study was to compare DC of two composites polymerized with different curing modes of two LED units. Materials and methods: For DC measurement, six samples were prepared for Tetric Ceram (TC) and Tetric EvoCeram (TEC) (both Vivadent, Schaan, Liechtenstein) each. Unpolymerized composite sample was placed between two Mylar-foils and pressed at 107 Pa to 0.1 mm thickness. Bluephase C8 (BC8) and Bluephase 16i (BC16) (both Vivadent, Schaan, Liechtenstein) with different curing modes: BC8-high power (HIP, 800 mW/cm2, 20 sec), low power (LOP, 650 mW/cm2, 30 sec), soft-start (SOF, 650 mW/cm2 first 5 sec, next 25 sec 800 mW/cm2) ; BC16– high power (HIP, 1600 mW/cm2, 10 sec), low power (LOP, 650 mW/cm2, 30 sec), soft-start (SOF, 650 mW/cm2 first 5 sec, next 10 sec 1600 mW/cm2) were used for photopolymerization. Curing tip was placed on the upper foil of the unpolymerized sample and polymerized with each mode. For determining DC, FTIR spectra of polymerized (P) and unpolymerized (U) samples were recorded using Perkin-Elmer spectrometer (Beaconsfield, Bucks, UK) and calculated according to formula: %DC=(1-P/U)x100%. Results: Results show better DC in case of polymerization with BC16 for all modes and composites. There is no significant difference between different modes for each material. In case of polymerization with BC16, the same DC was achieved in case of polymerization with HIP and SOF for both composites. The lowest DC for both composites was achieved in case of polymerization with LOP of both units. Conclusion: The main role of each clinician is to achieve satisfactory DC and long-lasting and clinically acceptable composite filling by choosing proper light intensity and curing time for photopolymerization.

degree of conversion; LED curing units

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