Intratubular crystal formation in the exposed dentin from nano-sized calcium silicate for dentin hypersensitivity treatment

Abstract

Objectives This study aimed to evaluate intratubular crystal formation from the experimental material consisting of dicalcium silicate and tricalcium silicate (C2S/C3S). Materials and Methods A total of twenty-four specimens were made by isolating 8 mm of the cervical part centered at the cementoenamel junction of extracted premolars. Twelve samples of the exposed upper dentin surface were treated with ethylenediaminetetraacetic acid followed by sodium hypochlorite to simulate sensitive dentin. The other twelve specimens were not treated and considered as controls. The experimental material consisting of C2S/C3S with a nano-scaled particle size was applied to the other twelve specimens by brushing for 10,000 strokes. Each group was randomly divided into four subgroups according to the period of immersion in phosphate-buffered saline (PBS) for 1, 30, 60, and 90 days. The specimens were sectioned longitudinally and examined via scanning electron microscopy and energy dispersion X-ray spectroscopy. Results The intratubular crystal was formed in PBS and densely filled the dentinal tubules over time. Crystal formation occurred at a depth of more than 50 µm from the dentin surface. The Ca/P ratio of formed intratubular crystals was 1.68 after three months. Conclusion Intratubular crystals were formed and grown in the dentin from nano-sized C2S/C3S particles under PBS, and the Ca/P ratio of the crystals was similar to that of hydroxyapatite. Clinical Relevance C2S/C3S with a nanoscale particle size can form intratubular crystals in PBS, and there is a possibility of reducing dentin hypersensitivity by blocking the dentinal fluid flow.