Polymerization of composites using pulsed laser

The quality of visible-light-cured composites depends on the capability of the light source to properly polymerize the material within a specified exposure time. In this study, the degree of conversion of different composite materials (hybrid and microfilled) of light and dark shades was compared after illumination by a standard curing unit and pulsed laser (lambda=468) respectively. The degree of conversion was measured by Fourier transform infrared spectroscopy. Results obtained by the analysis of the pulsed laser-induced polymerization were significantly higher for all the materials and shades observed. All values of the degree of conversion were lower for dark shades of all types of composites, regardless of the photopolymerization technique used. Besides the surface, better polymerization was recorded also at depths of 1.0, 2.0 and 3.0 mm, respectively. These values varied from 59.7%+/-2.14 to 84.5%+/-0.33 for pulsed laser (including all depths) caused by the saturation effect induced by high power laser pulses and from 42.7%+/-1.48 to 74.7%+/-0.99 for standard polymerization.