ABSTRACT
Objective@#To evaluate the effects of quercetin on dentin resistance to erosion and provide evidence-based recommendations for the prevention and therapy of dental erosion.@*Methods@#One hundred and twenty-eight dentin samples were prepared from 50 extracted human wisdom teeth (collected from Department of Oral Surgery, School and Hospital of Stomatology). Ninety-six samples were randomly divided into 8 groups using the following different soaking solutions: deionized water, ethanol (control groups), 12.300 mg/L sodium fluoride, 0.120 mg/L chlorhexidine, 0.183 mg/L epigallocatechin gallate (EGCG), and 0.075, 0.150 and 0.300 mg/L quercetin. In each group, twelve specimen was prepared. Before daily acid challenge, the samples were immersed in the respective solutions for 2 min, rinsed with deionized water, and immersed in artificial saliva for 2 h. The samples were then subjected to 4 cycles of in vitro acid challenges. This protocol was applied for 7 d. The surface microhardness (SMH) and surface profiles were measured before and after erosion using the surface microhardness tester and contact profilometry, respectively. The change in surface profiles and reduction in SMH were used to calculate the substance loss and reduction percentage of SMH (SMH%) respectively. Scanning electron microscope (SEM) images were taken to observe the surface morphology of the samples. Additionally, another thirty two samples were divided into 8 groups (n=4) as mentioned above. The specimens were treated with 10% phosphoric acid and desiccated, immersed in the respective solutions for 2 min, rinsed, and immersed in the artificial saliva at 37 ℃ for 7 d. The content of cross-linked carboxyterminal telopeptide of type Ⅰ collagen (ICTP) in the soaking solutions were measure quantitatively.@*Results@#Compared with the control groups, the application of chlorhexidine, quercetin, and EGCG were effective in preventing the surface softening and substance loss of human dentin after erosion. More specifically, the specimens treated with 0.300 mg/L quercetin exhibited the lowest SMH% [(8.75±4.95)%], the lowest surface substance loss [(2.26±1.16) μm], and the lowest contents of ICTP in the soaking solution [(5.72±0.88) ng], showing significant differences to the chlorhexidine and EGCG treated samples (P<0.05). No significant differences were found in the substance loss and ICTP contents in the three soaking solutions with different concentrations of quercetin(P>0.05). However, the specimens treated with 0.300 mg/L quercetin exhibited significantly lower SMH% than those treated with the other two concentrations of quercetin (P<0.05).@*Conclusions@#Within the limitations of the current study, immersion in the quercetin solution is effective in improving the dentin resistance to erosion by inhibiting the dentinal MMP. Among all the concentrations tested, 0.300 mg/L quercetin showed the best performance.