Includes the water system blend being the composition for dentistry which, the said water system blend, (i) below-mentioned system (A):< Conversion 1 > (In formula, a is integer 1 - 10, As for R1 hydrogen atom or the below-mentioned formula (Y) region< Conversion 2 > (In formula, As for X becoming independent, the oxygen atom, the sulfur atom or the NR basis (in formula, R can be the hydrogen atom, C1 6 alkyl group or the acyl basis) showing, L contains 1 - 20 carbon atoms, at the same time ether, thioether or the amino group or includes the further acidic basis optionally (a+b) it shows the organic residue of value, here, the said carbon atom primary and the second class aliphatic carbon atom, a+b which is selected from the second class fat cyclic carbon atom, and the aromatic carbon atom includes the carbon atom at least, said a+b the carbon atom each phosphoric acid derivative basis or the 2 (okisaariru) has connected with the derivative basis, b is integer 1 - 10) showing, R2 may be, being the same, differing, becoming independent, hydrogen, aryl group, or b 1 are the R1 region which is, but However, R at least as for one side of1 or R2 hydrogen is not) polymerization characteristic acidic phosphate monomer and, Polymerization characteristic N substitution alkyl acrylic acid monomer or acrylic acid amide monomer above (ii)1 kind and, (iii) organic water miscibile solvent and/or water and, (iv) polymerization initiator and, (v) inhibiter and/or stabilization medicine and, (vi) optional organic acid or inorganic acid and, (vii) optional filler and/or fluoride discharge chemical compound and,The composition for dentistry which includes the water system blend which is contained.水系混合物を含む歯科用組成物であって、該水系混合物が、(i)下記式(A):【化1】(式中、aは1~10の整数であり、R1は水素原子又は下記式(Y)の部位【化2】(式中、Xは独立して、酸素原子、硫黄原子又はNR基(式中、Rは水素原子、C1-6アルキル基又はアシル基であり得る)を示し、Lは、1個~20個の炭素原子を含有し、且つエーテル、チオエーテル又はアミノ基又はさらなる酸性基を任意に含む(a+b)価の有機残基を示し、ここで、該炭素原子は、第一級及び第二級脂肪族炭素原子、第二級脂環式炭素原子、及び芳香族炭素原子から選択される少なくともa+b個の炭素原子を含み、該a+b個の炭
