Fig. 4
XRD spectra of dentin slices surface. Spectrum 1, a natural dentin slice; Spectrum 2, a remineralized dentin slice following treatment with CPP–ACP combined with TPP for 21 days; Spectrum 3, a remineralized dentin slice following treatment just with CPP–ACP for 21 days; Spectrum 4, a remineralized dentin slice following treatment with only artificial saliva; Spectrum 5, a demineralized dentin slice. The PDF card 74-0565 showed the standard diffraction peak pattern of Ca10(PO4)6(OH)2. After 21 days of combined remineralization with TPP and CPP–ACP, the bulge almost completely disappeared at 25º–45º, and the (002) peak appeared, which was very close to the natural dentin diffraction pattern, indicating that most of the amorphous hydroxyapatite had transformed into a crystalline state