STUDY REGARDING THE INFLUENCE OF THE DISTANCE FROM LIGHT CURING UNIT TIP TO MATERIAL SURFACE AND OF THE LIGHT CURING MODE ON POLYMERIZATION EFFECTIVENESS OF A BULF FILL BASE COMPOSITE RESIN

Abstract

The aim of the study was to evaluate the influence of some characteristic of the light curing unit (polymeriyation mode and the distance between light curing tip to the surface of composite resin) on the efficiency of SDR® Plus bulk fill flowable base composite. U (universal), A2, and A3 shades was used in the study. Fiftyfive samples from each shade were prepared by injection the flowable resin in cylindrical plastic molds with the intern diameter of 5 mm. Three types of plastic molds according to their hight were used: 6 mm, 8 mm, and 10 mm. The tip of the light curing unit was placed on top of the mold and composite resin was light cure for 20 seconds for U shade and 40 seconds for A2 and A3 shades. Top and bottom surface Vickers hardness was determined using a digital microhardness. The hardness ratio of each specimen was also calculated Polymerization efficiency of SRD® Plus bulk-fill flowable base composite resin was not affected by the distance from the light sourse to the surface of the material and the light curing mode. Staggared polymerization mode of the light curing unit determines slightly low values of surface hardness when comparing to inclined and normal polymerization modes. Darker shades of bulf fill flowable base composite resin seems to present decreased surface hardness when comparing to ligther shades irrespective the distance from the light curing unit to the material surface and the mode of polymerization.

Keywords

• bulk-fill flowable composite
• srd® plus
• surface hardness