Effect of chitosan and hydroxyapatite nanocomposite on dentin erosion: An in-vitro study

Aim: To evaluate the dentinal tubule occlusion and collagen stabilization potential of nanohydroxyapatite (nHAp) and nanochitosan (nCH) combination paste on eroded dentin surface. Materials and Methods: In this in-vitro study, nHAp was prepared using the microwave-accelerated wet chemical synthesis method and nCH was made by the ionic gelation technique. The particles were characterized separately under dynamic light scattering and made into a paste by mixing them at a ratio of 1:1, which was further analyzed using Fourier-transform infrared spectroscopy (FTIR). Dentin slabs were prepared from 32 extracted human molars and subjected to erosion by exposing to 3% citric acid for 5 min. They were divided into four groups by convenience sampling method (n = 15): group I-control (no treatment); group II-nHAp; group III-nCH; group IV-nHA-nCH paste. All dentin samples were treated according to their respective groups by the active application of pastes using microbrushes for 1 min everyday for 14 days. Later, the samples were subjected to FTIR and scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX) analysis. Statistical analysis was done using one-way analysis of variance (P 0.05). Results: SEM-EDX revealed complete occlusion of dentinal tubules in the nHA-nCH group with HAp deposits on the surface. The Ca/P ratio of various groups was significantly different from each other (control group-1.05, nHAp-1.64, nCH-1.14, and nHA-nCH-1.71) (P 0.05). The FTIR spectra marked the presence of amide I peak in nCH and nHA-nCH groups, indicating collagen stabilization. Conclusion: The nHA-nCH paste shows a potential for tubular occlusion and stabilizes both the inorganic and organic components of eroded dentin, respectively.