Reversal of Compromised Bond Strength of Bleached Enamel Using Cranberry Extract as an Antioxidant: an In Vitro Study.

BACKGROUND AND OBJECTIVES: Bleaching reduces the bond strength of enamel, if adhesive restorations are carried out immediately. Reversal of compromised bond strength of bleached enamel by application of antioxidant agents has been reported in the literature. The aim of the study is to assess the neutralizing effect of 6% cranberry (CB) solution on the bond strength of bleached enamel compared with that of 10% sodium ascorbate (SA) solution. MATERIALS AND METHODS: Enamel surfaces of 64 extracted human premolar teeth were randomly divided into four groups based on the antioxidant used. Further subgrouping was done in Groups II, III, and IV dividing each group into subgroup A and subgroup B of eight teeth each based on whether the bonding was performed immediately or after a delay of 14 days postbleaching respectively. Shear bond strength (SBS) of the specimens was measured using a Universal testing machine. The data were then tabulated and statistically analyzed using one-way ANOVA (analysis of variance) and Tukey's post-hoc parametric tests. A p-value of <0.05 was considered statistically significant. RESULTS: The SBS measurements were compared among the four groups including the subgroups. The SBS was highest in the SA delayed bonding group and lowest in the bleached immediate bonding group. CONCLUSION: A 10% SA solution has proven superior to 6% CB solution in the reversal of compromised bond strength following bleaching.

The effect of hydrogen peroxide gel on the color of the inner section of extracted teeth / 实用口腔医学杂志

Objective:To observe the color change of tooth i nduced by hydrogen peroxide gel. Method:12 extracted teeth were randomly assigned to two groups (n=6) and treated with 350 g/L and 75 g/L hy drogen peroxide gel respectively. One of the 6 samples in each group was used as the control. The bleaching gel was placed onto the enamel surface of the sample s. In 350 g/L gel group digital photographs were taken just before,10 and 30 min after the process, in 75 g/L gel group digital photographs were taken before an d 1.5?N(N=0,1,2,3,4,5,6,7) hours after the process respectively. All photograph s were taken at the same illuminating conditions and photographic parameters wer e analyzed with Photoshop7.0 software. Results:10.5 h after trea tment in the 75 g/L gel group L *, a * and b * values on the teeth surface were in creased(+) or decreased(-) by +4.5,-1.4 and -0.5,those on the inner sections 2.7 ,-1.0 and -0.8,respectively. 30 min after treatment in the 350 g/L gel group L *, a * and b * values on the teeth surfaces were increased(+) or decreased (-) by +1.9,-0.6 and 0,those on the inner sections +0.4,-0.4 and -0.6,respectively. Conclusion:Effective bleaching effect may be obtained in 10~30 min b y 75 g/L or 350 g/L hydrogen peroxide gel on teeth surface and in inner dentin. 75 g/L hydrogen peroxide bleaching gel may produce more reliable and save effect than 350 g/L.