engleski

Biological Properties of Blue Light Radiated from Different Dental Cured Binding Units

The attempt to increase dental resin polymerization quality discharges the commercially available high power light density dental curing units. Widespread worry in both, patients and dentists rises with regard to the adverse effects on the pulp tissue since the emitted visible blue light belongs to the nonionizing radiation of electromagnetic spectrum. Two devices, halogen curing lights of EliparÒ TriLight, ESPE Dental AG (Germany) unit and Bluephase C8® LED light source (Vivadent, Schaan, Lichtenstein) have been evaluated and compared for radiation effects on cell viability, colony-forming ability (CFA) and proliferation of continuous cell culture. Quartz-tungsten-halogen light source emits radiation of the wavelengths between 400 and 515 nm. This halogen light source operates in the three illumination modes, medium (M), exponential (E) and standard (S). The total irradiance or the light intensity was 800 mW/cm2. Bluephase C8® LED light source emits radiation between 400 and 500 nm. The investigation included low (L), soft start (S) and high (H) illumination mode. Light intensity values were: H mode 740.2±9.4 mW/cm2, S mode 735.9±0.7 mW/cm2, and L mode 418.9±2.6 mW/cm2. Cell samples were illuminated in triplicates by both dental curing units for 20, 40 and 80 seconds, particularly. The cell viability was determined by the trypan blue exclusion test, CFA by count of colonies on 7th post-exposure day, cell proliferation by the cell counts for each illumination mode and duration of exposure during five post-exposure days. Regardless the both experimental conditions applied, cell viability was unaffected and remained in the range of the control ones. Regardless to exposure or illumination modes of EliparÒ TriLight, ESPE halogen light curing unit CFA was not significantly depressed. Cell proliferation was significantly decreased in samples exposed to M mode for 80 s on post-exposure day 3 and 4. On the same postexposure days the proliferation of cells exposed to E and S mode showed a significant inhibition after 20, 40 and 80 s of exposure. In the comparison with controls, treatment of cells with high-performance LED diode shows that CFA was not found to be significantly lower. Significant decrease in cell proliferation was recorded on the 4th post-exposure day for S and H mode independently of exposure time. Proliferation inhibition was noted on the 3rd day with S for 80 s, H for 40 and 80 s, also with S and H for 80 s on the 2nd post-exposure day. Disrupted cellular functionality and time- and dose dependent inhibition of cell proliferation might be ascribed to the photo curing blue light intensity and duration of exposure. In comparison with halogen TriLight curing unit, a high-performance Bluephase light emitting diode (LED) expressed less dangerous biological effects.

In vitro; Optical;

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