To provide an organic and inorganic composite filler which gives excellent
surface smoothness similar to that of a natural tooth, low polymerization
shrinkage, high X-ray imaging property and high mechanical strength to a
dental restoration material composite, an organic and inorganic composite
filler used for a dental restoration material is produced by curing and
pulverizing a (meth)acrylate compound including 50 to 80% by weight of a
glass powder having a maximum particle diameter of 5 .mu.m or less, an
average particle diameter from 0.05 to 2 .mu.m, and X-ray imaging
property, and 10 to 40% by weight of a metal compound having an average
particle diameter from 0.005 to 0.3 .mu.m and X-ray imaging property at
the maximum of 90% by weight in total, where the organic and inorganic
composite filler has preferably an average particle diameter from 10 to
30 .mu.m.