Comparison of microhardness of a composite core in two different placement techniques - An invitro study

The incremental placement technique of composite is acceptable as a standard method. Time consuming and high sensitivity of this technique, especially in large tooth preparations such as composite build up core are problems of this method. The purpose of this study was laboratory comparison of microhardness values in one kind of composite core at complete building tooth with incremental and Bulk placement techniques. Ten cylindrical samples of clearfil photo core-light cure(Kuraray/Japan), (Translucent, Single Shade) composite were prepared up to 9mm in Insulin syringes. Half of them were built with incremental placement technique by 2 mm increments and the other half were built with bulk placement technique.Light curing was done with output irradiance of 650 mw/cm2 for 40 seconds. Samples were cut in longitudinal position and were mounted in Epoxy resin. Vicker's microhardness was measured from surface of every samples in the 1,2,3,4,5,6,7,8,9 mm depths. Statistical Analysis were done with two-way ANOVA (P