MICROHARDNESS AND POROSITY OF CLASS-2 LIGHT-CURED COMPOSITE RESTORATIONS CURED WITH A TRANSPARENT CONE ATTACHED TO THE LIGHT-CURING WAND

A new technique for curing class 2 composite fillings was investigated with respect to microhardness and porosity in the cervical part of th e restorations. The technique Is based on a plastic transparent cone t hat is attached to the curing wand. Before polymerizing the cervical p ortion, the cone is pressed down into the material in the direction of the floor of the approximal box. When the light is activated, it conc entrates in the tip of the cone, from where it is distributed into the composite material. In order to compare this technique with conventio nal curing, standardized class 2 cavity preparations were made In bras s blocks. Four different composite materials were used for 20 restorat ions each: Heliomolar, Herculite XR, Occlusin, and P-50. Ten restorati ons of each material were cured using the conventional technique (in t wo portions), and in the remaining 10 restorations the cervical portio n was cured with the transparent cone. The irradiation time was 60 sec onds in all instances. The Vickers hardness of the cervical approximal surfaces was measured after one and 24 hours. The surfaces were photo graphed in a stereomicroscope, and the numbers of porosities were coun ted on black-and-white prints. Using the new technique, a significant increase in microhardness was obtained in all four materials. The incr ease ranged from 19% to 57%. Regardless of curing, technique, there we re considerable differences in microhardness among the materials. For two of the materials a significant correlation was found between the u se of the cone and a decreased number of porosities.