THE EFFECT OF ADDING SOME CHEMICAL MATERIALS ON THE COMPRESSIVE STRENGTH AND SURFACE HARDNESS OF DENTAL STONE

To determine the effect of some chemical materials on the compressive strength and surface hardness of dental stone. Material and Methods: three types of chemical materials (rosin, nigella stavia oil and sodium lauryl sulfate) were incorporated into three kinds of type III dental stone (Zeta, Elite and Dental stone) at four concentrations (0.5%, 1%, 1.5% and 2%).The collected data of compressive strength and surface hardness were subjected to the descriptive analysis (mean and stander deviation), student T test (to evaluate the difference between standard and experimental groups) and one way analysis of variance (ANOVA) (to show if there are significant differences among experimental groups). Results: revealed that the incorporation of these chemical materials into each type of dental stone resulted in changing their evaluated physical properties; this change varies with the type, concentration of the added chemical material and type of dental stone being used. Conclusion: The highest values of compressive strength and surface hardness were recorded with the addition of rosin into each of Zeta, Dental stone (at a concentration of 1%) and Elite stone (at a concentration of 1.5%). Also the addition of nigella sativa stone oil increases in the compressive strength and surface hardness of Zeta and Dental stone when this materials added at a concentration of 1% and at a concentration of 0.5%when it is added to Elite.