Water/Ethanol Rinse Affects Proanthocyanidins or Quercetin Treated Dentin Collagen Stability

Objectives: To assess the protective effects on demineralized dentin resulting from treatment with quercetin compared to Grape Seed Extract (GSE) followed by either a deionized water or ethanol rinse.
Methods: Dentin films obtained from non-carious human third molars were demineralized and treated with 1% GSE or 1% quercetin with 1 minute and 60 minute treatment times. Untreated films were assigned as controls. GSE treated, quercetin treated, and control films were rinsed using either deionized water or ethanol (30 minutes). Forty films were used per experimental group. All films were then digested with 0.1% collagenase type I, dried, and post-digestion weight loss was assessed. A hydroxyproline analysis was also performed. Additional dentin films were analyzed by FTIR. Data was analyzed using an unpaired Student’s t-test (α = 0.05).
Results: Weight loss was lowest after 60 minutes for both treatments. GSE treated films showed significantly reduced weight loss when compared to quercetin regardless of rinsing solutions (p<0.05), and the control group showed the highest weight loss (p<0.05). Quercetin showed intermediate results when rinsed with deionized water, however after ethanol rinsing the weight loss was similar to the control group (p>0.05). No statistical differences were found among the experimental groups in the hydroxyproline analysis. FTIR spectra revealed broadening of the amide peaks indicating cross-linking of GSE to dentin with the exception of the group treated for 1 minute and rinsed with ethanol. Broadening of the amide peaks was slight with quercetin treatment and absent after ethanol rinsing in comparison to the control group.
Conclusions: GSE treatment demonstrated higher cross-linking ability and greater protection from collagenase digestion in comparison to quercetin, which provided less protection under all conditions. Quercetin rinsed with ethanol performed similar to the controls indicating that most of the quercetin was removed during the rinsing process. Funded by UMKC SOD Summer Scholars program.