One-component-type dentinal tubule sealant

A dentinal tubule sealant including apatite particles (A) having an average particle diameter of 500 nm or less, a filler (B) having an average particle diameter of 1 to 10 μm, and a dispersant (C), wherein the weight ratio (A/B) of the apatite particles (A) to the filler (B) is 0.05 to 15, the dentinal tubule sealant contains 15 to 95 parts by weight of the dispersant (C) relative to 100 parts by weight in total of the apatite particles (A) and the filler (B), and the total amount of the apatite particles (A), the filler (B), and the dispersant (C) is 85 parts by weight or more relative to 100 parts by weight of the dentinal tubule sealant. There is thereby provided a dentinal tubule sealant excelling in dentinal tubule sealability immediately after treatment, durability of dentinal tubule sealing, ease of operation, and storage stability.