Evaluation the effect of mixed different types of water with dental stone on the compressive strength.

The strength of gypsum products is generally expressed in terms of compressive strength and normally measured under compression. It increases rapidly as the materials harden after the initial setting time. However, the amount of water present in the set product definitely affects its strength.This study is designed to evaluate and compare the effect of water used (tap water, distilled water, tap water with powder of stone, distilled water with powder of stone, tap water with impurities of stone, distilled water with impurities of stone) on compressive strength of dental stone.Sixteen (60) specimens were prepared from stone, (10) specimens were considered as a control group (tap water) the remaining specimens were divided into five main group (10) specimens of distilled water, (10) specimens of distilled water with powder of stone (10) specimens of distilled water with impurities of stone (10) specimens of tap water with powder of stone, (10) specimens of tap water with impurities of stone.The result showed that the group of distilled water has increase the compressive strength than control group (tap water), and group of tap water with impurities of stone has decreased compressive strength than control group (tap water).Finally, it can be concluded that the type of surface treatment have an important parameter in the improvement of dental stone