Non-solvent dental adhesive composition

A non-solvent dental adhesive composition, comprising:

• an acid group-containing polymerizable monomer (A);
• a hydrophobic polymerizable monomer (B) having no acid group;
• and
• a water-soluble photopolymerization initiator (C) having a solubility of 10 g/L or more in water at 25° C.,
• wherein the water-soluble photopolymerization initiator (C) is at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2):
• wherein R1, R2, R3, R4, R5, and R6 are each independently a linear or branched alkyl group comprising 1 to 4 carbon atoms or a halogen atom;
• M is a hydrogen ion, an alkali metal ion, an alkaline-earth metal ion, a magnesium ion, a pyridinium ion comprising an optionally substituted pyridine ring, or an ammonium ion represented by HN+R7R8R9, wherein R7, R8, and R9 are each independently an organic group or a hydrogen atom;
• and
• n represents 1 or 2.