Investigating the Intensity Dynamics of the Photopolymerizer Light Flux in Restorative Materials

On the modern dental market, innovative restorative materials with optimized properties that have universal or limited application are constantly appearing. The latter should include fluid photocomposit, which are often used to create a "super adaptive" layer in restorations, for sealing fissures, sealing small carious cavities, in cases of a "tunnel" preparation for the restoration of contact surfaces, and the like. But the peculiarities of light influence for solidification of these materials in terms of regime or intensity of light flow are not sufficiently studied. The purpose of this work was to study the intensity dynamics of the light flux of the LED photopolymerizer in samples of fluid photocomposit materials of different thicknesses. Materials and methods. In the course of laboratory research, we made up samples of fluid photocomposit materials using a split-shaped form. We also used nanophotocomposit material, which solidified at the expense of the simultaneous influence of the light flux on the material and the adhesive system, were made by means of a split-shaped form. A total of 160 samples of enamel and opaque shades with thickness of 1.0 mm and 2.0 mm were investigated. The loss in the intensity of the light flux of the LED photopolymerizer with the initial intensity of 1000 mW /cm2 in the samples were studied using an experimental setup. The results were presented as a percentage of the initial level. Results and discussion. The maximum intensity of the light flux passing through samples of materials of 1.0 mm and 2.0 mm thickness enamel shades was recorded for the strengthened SDR, Dentsply, and the filtrate composit material Filtek Ultimate, 3M ESPE. The samples of these materials were polymerized simultaneously with the adhesive system. The minimum intensity indices for the same parameters were set in samples of Filtek Ultimate Flowable, 3M ESPE enamel shade. As for opaque shades, the lowest indicators of the light flux intensity were determined in samples of both thickness parameters of the same liquid material. The significantly higher intensity of the light flux, compared with the previous one, was in studying the samples of nanotech composit material Filtek Ultimate, 3M ESPE, opaque shade, hardening of which was carried out simultaneously with the adhesive system. Conclusions. The dynamics of the light flux intensity of the LED photopolymerizer in samples of fluid photocomposit materials were influenced by opacity, degree of filling, and the filler particles size in the material. If the thickness of a liquid-cooled photocomposition material layer of enamel shades was no more than 2.0 mm, it was possible to use the light flux of LED photopolymerizer at intensity of 1000 mW /cm2 for its hardening. However, in the case of opaque shade application, a photopolymerizer with a higher intensity of light flux should be chosen. We can also apply layer-laying material with each layer thickness up to 1.0 mm.