Lithium disilicate glass-ceramics are used for high quality dental material due to its good aesthetic properties and appropriate mechanical strength.The glass-ceramics are fabricated by nucleation and crystallization of parent glass by heat-treatment.It has been known that the microstructure and properties of glass-ceramics are affected by nucleation agent and glass composition.However,the effect of ratio of nucleation agent and glass modifiers in glass-network has not been studied explicitly in lithium disilicate dental materials until recently even though the role of each modifiers have searched by one and one.