The dentin tubule occlusion effects of desensitizing agents and the stability against acids and brushing challenges

To investigate the effects of desensitizing agents on dentin tubule occlusion, acid and tooth brushing challenge, and microhardness change of human dentin.

Partially demineralized dentin slabs were divided into four groups (n = 30): (1) Control, (2) Non-desensitizing toothpaste, (3) Pro-Argin toothpaste, (4) CPP-ACP paste. The specimens were treated with these dentifrices for 2 minutes/day and soaked in artificial saliva (AS) for 24-hour remineralization. Then the dentin discs were divided into three subgroups for removal resistance tests: acid challenge, mechanical brushing challenge and blank control. Changes in dentin morphology were observed using scanning electron microscopy (SEM). Vickers microhardness measurements were performed at baseline and after 24-hour remineralization for all groups.

A surface layer and intra-tubular crystals were observed in SEM imaging of Pro-Argin toothpaste and CPP-ACP paste groups, which occluded most of the dentin tubules for those specimens. But the dentin tubules were opened after the acid challenge again. Moreover, the dentin microhardness showed a slight increase after 24-hour AS immersion. The percentage microhardness gain (PMG) values of these two groups were 5.4% and 5.1% respectively, which were significantly higher than the other groups (P < 0.05).