Daily toothbrushing with and without an abrasive dentifrice was performed on the ground surfaces of human cervical dentin attached to resin plates, which had been exposed to the oral cavities of 4 subjects for 8 weeks. Brushing with a dentifrice containing calcium hydrogen phosphate as an abrasive caused most of the dentinal tubules to open. The patency of dentinal tubules is thought to induce dentin hypersensitivity. Brushing without a dentifrice, on the other hand, resulted in occlusion of the dentinal tubules with organic pellicle‐containing minerals. Furthermore, abrasion did not occur; however, no bacterial plaque or dental calculus were retained. The occluded tubules which were distributed over the entire dentin surfaces will likely prevent hypersensitivity. Such organic‐mineral materials occluding the tubules can be derived from saliva and embedded by the brushing. We suggest that use of a non‐abrasive dentifrice will prevent or reduce dentin hypersensitivity in the cervical regions. J Periodontol 1994;65:291–296.