Abstract
Objective
The aim of the present study was to evaluate the effect of quercetin on the acid resistance of human dentin through both laboratory and clinical studies.
Methods
Two hundred and twelve dentin blocks (2 mm × 2 mm × 2 mm) were prepared and used. For the laboratory study, dentin specimens were randomly divided into 8 groups (n = 12): deionized water, ethanol, 1.23 × 104 μg/ml sodium fluoride (NaF), 120 μg/ml chlorhexidine, 183.2 μg/ml epigallocatechin gallate (EGCG), and 75 μg/ml, 150 μg/ml, and 300 μg/ml quercetin (Q75, Q150, and Q300). The specimens were treated with the respective solutions for 2 min and then subjected to in vitro erosion (4 cycles/d for 7 d). The surface microhardness loss (%SMHl), erosive dentin wear, and surface morphology were evaluated and compared. For the impact on MMP inhibition, the release of crosslinked carboxyterminal telopeptide of type I collagen (ICTP) and the thickness of the demineralized organic matrix (DOM) were measured using additional dentin specimens. For the clinical study, the specimens were treated with NaF or Q300 for 2 min and then subjected to in vivo erosion (4 cycles/d for 7 d). The %SMHl and erosive dentin wear of the specimens were measured to determine whether quercetin similarly inhibits erosion in situ.
Results
The quercetin-treated group had a significantly lower %SMHl and erosive dentin wear than any other group, and the effect was concentration-dependent in vitro (P < 0.05). Dentin treated with quercetin produced significantly less ICTP and had a thicker DOM than the control dentin (P < 0.05). After in vivo erosion, the %SMHl and erosive dentin wear of the Q300 group were significantly lower than those of the control group (P < 0.05).
Significance
The application of quercetin was shown, for the first time, to increase the acid resistance of human dentin, possibly through MMP inhibition and DOM preservation.
Jiang, Neng-Wu