Effective dentinal tubule occlusion induced by polyhydroxy-terminated PAMAM dendrimer in vitro

Abstract

In recent years, poly (amido amine) (PAMAM) dendrimers have become a research focus in biomineralization fields. In this study, polyhydroxy-terminated PAMAM dendrimers (PAMAM-OH) were used to induce dentinal tubule occlusion. Demineralized dentin samples were coated with the second generation or the fourth generation PAMAM-OH solutions (G2-PAMAM-OH or G4-PAMAM-OH, 1 mg mL⁻¹). The binding capacity of PAMAM-OH to demineralize dentin was tested by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Then the G4-PAMAM-OH-treated samples were immersed in artificial saliva for different periods. The remineralized samples were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). 6 wt% citric acid (pH 1.5) solutions were used to evaluate the effect of dentinal tubule occlusion. Cytotoxicity assay on dental pulp cells was carried out to examine the biocompatibility of G4-PAMAM-OH. The results of ATR-FTIR showed that G4-PAMAM-OH had a stronger binding capacity towards demineralized dentin than G2-PAMAM-OH did. After the remineralization, the G4-PAMAM-OH-treated samples showed obvious remineralization compared to the control group and the dentinal tubule occlusion was effective even after acid attack. The results of EDS and XRD confirmed that the regenerated minerals induced by G4-PAMAM-OH were hydroxyapatite (HA). Cytotoxicity assay showed that G4-PAMAM-OH had hardly any cytotoxicity towards dental pulp cells. In conclusion, G4-PAMAM-OH has great potential to be used in the treatment of dentin hypersensitivity in the future.