Biomineralization reaction from nanosized calcium silicate: A new method for reducing dentin hypersensitivity

This study assessed the ability of experimental materials consisting of dicalcium silicate (DCS) and tricalcium silicate (TCS) with nanosized particles to form intratubular crystals under phosphate-buffered saline (PBS) and the effect on dentin permeability reduction.

By isolating the cervical part of the extracted premolars, 195 specimens were obtained. Two experimental materials (DCS/TCS and TCS) were applied to the dentin surface by brushing and stored in PBS (n = 65). Another 65 specimens were not treated. Each group was randomly divided into five subgroups based on the PBS immersion period (1, 15, 30, 60, and 90 days, n = 10). The dentin permeability was measured, and the hydraulic conductance, Lp (%), was calculated. After acid challenge with 1 M acetic acid, Lp (%) was remeasured. Data were analyzed using two-way analysis of variance and Fisher's least significant difference test (α = 0.05). Three specimens of each subgroup were longitudinally sectioned and examined using scanning electron microscopy and a field emission-electron probe micro analyzer.

The Lp (%) of the experimental groups gradually decreased over time (P < 0.05). The hydroxyapatite-like crystals that grew were observed and found to have a Ca/P ratio similar to that of hydroxyapatite. The crystals remained after the acid challenge, and the Lp (%) was not significantly different from that before acid treatment.

Intratubular crystals formed from the experimental materials consisted of DCS and TCS and were resistant to acid. These crystals significantly reduced dentin permeability.