The present invention relates to a dental composition comprising a polymerization initiator system comprising an aromatic tertiary phosphine compound, as well as to a use of said aromatic tertiary phospine compound for the preparation of a photocurable dental composition.In particular, the present invention relates to a dental composition comprising(a) one or more compounds having at least one polymerizable double bond；(b) a polymerization initiator system comprising(b1) a sensitizer； and(b2) an aromatic tertiary phosphine compound of the following formula (I): Z-R (I)whereinZ is a group of the following formula (II) R1(Ar)P- (II)whereinR1 represents a substituted or unsubstituted hydrocarbyl group；Ar represents a substituted or unsubstituted aryl or heteroaryl group；R is a substituted or unsubstituted hydrocarbyl group or a group LZ', whereinL is a substituted or unsubstituted divalent hydrocarbyl group which may contain a linkage selected from an ether linkage, a thioether linkage, an ester linkage, an amide linkage, and a urethane linkage andZ' has the same meaning as Z, whereby Z and Z' may be the same or different；wherein the group R1 and Ar may be substituted by one or more groups selected from a hydroxyl group, an oxo group, a -NR2R3 group (wherein R2 and R3, which may be the same or different, are selected from a hydrogen atom and C1-6 alkyl groups), a carboxyl group, and a group having a polymerizable double bond, andR and L may be substituted by one or more groups selected from a hydroxyl group, an oxo group, a -NR2R3 group (wherein R2 and R3, which may be the same or different, are selected from a hydrogen atom and C1-6 alkyl groups), a carboxyl group, and a group having a polymerizable double bond.
