Nerve-targeted desensitizing toothpastes occlude dentin tubules and induce mineral precipitation

To examine the laboratory dentin tubules occlusion and mineral precipitation capability of two potassium salts-containing desensitizing toothpastes.

40 dentin disks were obtained and divided into four groups, including artificial saliva (AS), distilled water (DW), Sensodyne Freshmint (SF) and Colgate Sensitive (CS). Dentin permeability measurement was performed after EDTA etching, initial brush, 3-day brush, 7-day brush and citric acid challenge, respectively. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used to monitor the variation of mineral content before and after treatments. The ultra-morphology of dentin surface was examined using scanning electron microscopy (SEM) to evaluate tubule occlusion.

The two potassium salts-containing desensitizing toothpastes significantly reduced dentin permeability to less than 40% after 7-day treatment (P<0.05). The ATR-FTIR analysis showed increase of the intensity of the phosphate peak after a 7-day brushing period using both of the tested toothpastes. However, the dentin permeability significantly increased and the intensity of phosphate peak decreased after acid etching for all groups. The SEM examination revealed partially occluded dentin tubules after toothpaste treatments, but after the acid challenge the tubules were opened again.