A method for manufacturing a zirconia sintered body includes molding a powder composition that has a yttria content of more than 3% by mole and 5.2% by mole or less and that contains a first zirconia powder having a yttria content of 2% by mole or more and 4% by mole or less and a second zirconia powder having a yttria content of more than 4% by mole and 6% by mole or less to obtain a green body, and sintering the green body to obtain a sintered body.

Provided is a curable composition containing a polymerizable monomer (A), an organic-inorganic composite filler (B), and a polymerization initiator (C), wherein the organic-inorganic composite filler (B) includes an organic resin matrix (b1) and a spherical inorganic filler (b2) having an average primary particle size of 230-1000 nm, 90% or more of the number of individual particles constituting the spherical inorganic filler (b2) are present in a range of 5% greater or less than the average primary particle size, and the curable composition satisfies the following formulas (1) and (2):
nP<nF.sub.b2  (formula 1)
and nM.sub.b1<nF.sub.b2  (formula 2) In the formulas, nP represents the refractive index of the polymer of the polymerizable monomer (A) at 25° C., nF.sub.b2 represents the refractive index of the spherical inorganic filler (b2) at 25° C., and nM.sub.b1 represents the refractive index of the organic resin matrix (b1) at 25° C.

Provided is a curable composition containing a polymerizable monomer (A), an organic-inorganic composite filler (B), and a polymerization initiator (C), wherein the organic-inorganic composite filler (B) includes an organic resin matrix (b1) and a spherical inorganic filler (b2) having an average primary particle size of 230-1000 nm, 90% or more of the number of individual particles constituting the spherical inorganic filler (b2) are present in a range of 5% greater or less than the average primary particle size, and the curable composition satisfies the following formulas (1) and (2):
nP<nF.sub.b2  (formula 1)
and nM.sub.b1<nF.sub.b2  (formula 2) In the formulas, nP represents the refractive index of the polymer of the polymerizable monomer (A) at 25° C., nF.sub.b2 represents the refractive index of the spherical inorganic filler (b2) at 25° C., and nM.sub.b1 represents the refractive index of the organic resin matrix (b1) at 25° C.

Provided is a curable composition comprising a polymerizable monomer (A); spherical particles (B) having an average primary-particle diameter in a range of 230 nm to 1,000 nm; and a polymerization initiator (C), in which 90% or more of individual particles constituting the spherical particles (B) lies in a range of ±5% based on the average primary-particle diameter, and the refractive index of the spherical particles (B) is larger than the refractive index of a polymer of the polymerizable monomer (A). When a 1 mm-thick cured product is formed from the curable composition and the Y value (Yb) of the colored light of the cured product on a black background and the Y value (Yw) of the colored light of the cured product on a white background are each measured using a color difference meter, the ratio therebetween, Yb/Yw, being within a range of 0.2 to 0.5.

Provided is a curable composition comprising a polymerizable monomer (A); spherical particles (B) having an average primary-particle diameter in a range of 230 nm to 1,000 nm; and a polymerization initiator (C), in which 90% or more of individual particles constituting the spherical particles (B) lies in a range of ±5% based on the average primary-particle diameter, and the refractive index of the spherical particles (B) is larger than the refractive index of a polymer of the polymerizable monomer (A). When a 1 mm-thick cured product is formed from the curable composition and the Y value (Yb) of the colored light of the cured product on a black background and the Y value (Yw) of the colored light of the cured product on a white background are each measured using a color difference meter, the ratio therebetween, Yb/Yw, being within a range of 0.2 to 0.5.

An oral varnish comprising a combination of two different viscosity dimethicone components, wherein the difference between the two different viscosity dimethicone components is about 2.0 million cP or greater; and comprising at least one active ingredient, which is preferably a fluoride donor.

To provides a polymerizable composition having high storage stability and high color stability. To provide a two-paste type dental polymerizable composition of the present invention is a two-paste type dental polymerizable composition comprising a first paste containing (A) at least one kind of polemerizable monomer, an (B) organic peroxide as a chemical polymerization initiator, and a (C) basic filler, and a second paste containing (A) at least one kind of polemerizable monomer, a (C) basic filler and an (D) aromatic amine compound as a chemical polymerization accelerator, wherein the second paste contains 30 to 80 parts by weight of the (C) basic filler based on 100 parts by weight of the total amount of the second paste.

To provides a polymerizable composition having high storage stability and high color stability. To provide a two-paste type dental polymerizable composition of the present invention is a two-paste type dental polymerizable composition comprising a first paste containing (A) at least one kind of polemerizable monomer, an (B) organic peroxide as a chemical polymerization initiator, and a (C) basic filler, and a second paste containing (A) at least one kind of polemerizable monomer, a (C) basic filler and an (D) aromatic amine compound as a chemical polymerization accelerator, wherein the second paste contains 30 to 80 parts by weight of the (C) basic filler based on 100 parts by weight of the total amount of the second paste.

Provided are a zirconia sintered body capable of being widely used as a dental material, in particular, a zirconia sintered body capable of being applied to both a dental material for a back tooth and a dental material for a front tooth and a simple and easy method for manufacturing the zirconia sintered body. The method for manufacturing a zirconia sintered body includes a molding step of molding a powder composition that has an yttria content of more than 3% by mole and 5.2% by mole or less and that contains a first zirconia powder having an yttria content of 2% by mole or more and 4% by mole or less and a second zirconia powder having an yttria content of more than 4% by mole and 6% by mole or less to obtain a green body, and a sintering step of sintering the green body to obtain a sintered body.

To provide an organic-inorganic composite filler containing; a polymerizable monomer (a) having at least one functional group selected from the group consisting of —OH group, —NH— group, and —NH.sub.2 group, a polymerizable monomer (b) having no functional group selected from the group consisting of —OH group, —NH— group, and —NH.sub.2 group, a polymerization initiator (c), an inorganic filler (d), and a silane compound (e) which generates —OH group by hydrolysis.