Effects of various hydrogen peroxide bleaching concentrations and number of applications on enamel

Abstract

Aim: To evaluate the effects of three hydrogen peroxide (HP) concentrations on enamel mineral content (MC), following three peroxide applications and using three methods to measure the MC. Methods: Forty samples were obtained from bovine incisors and randomly divided into 4 groups (n=10). The control group remained untreated, while the experimental groups were tested for three HP concentrations (10%, 35% and 50%). The HP gel was applied 3 times on the enamel surface for 30 min per application and the samples were analyzed after each application. The MC of the enamel was determined before and after bleaching using Fourier transform (FT-Raman) spectroscopy and micro energy-dispersive x-ray fluorescence spectrometry (µEDXRF). The calcium (Ca) lost from the bleached enamel was quantified with an atomic absorption spectrometer (AAS). The data were analyzed statistically by ANOVA, Tukey and Dunnett´s tests (p<0.05). Results: The FT-Raman showed a decrease in MC for all bleaching treatments, without influence of the different HP concentrations or the number of applications. µEDXRF did not detect any changes in MC. Conclusions: Ca loss was observed by the AAS, with no difference among the three HP concentrations. The FT-Raman and AAS analyses detected MC reduction and Ca loss after HP bleaching.

Tribological properties of diamond nanoparticle additive in water under a lubrication between steel plate and tungsten carbide ball

“…On the ball wear scars lubricated by both distilled water and DNP dispersions, the Raman spectra showed no peaks between 1200 and 2000 cm −1 . The peaks at 1070 cm −1 were observed that can be attributed to stretching and bending modes of carbonate in WC ball itself (Berger et al, 2014;Ma & Du, 2008;O'Donnell, Candarlioglu, Miller, Gentleman, & Stevens, 2010). It is summarized from the Raman spectra that DNPs existed in the steel plate surfaces and did not on the WC ball surfaces after the DNP dispersion lubrication.…”

Influence of Post-Bleaching Time Intervals Using 37% Carbamide Peroxide on Dental Substrate Adhesion

“…This event can be explained by the possibility that repair of morphological and structural dental changes occur during the time elapsed between bleaching and restorative procedure due to the amount of minerals precipitated in the saliva (BASTING, 2001) is lower than in the enamel, since organic part is also affected. The changes in dentin composition occur due to the decrease of calcium and phosphorus in the post-bleaching procedure, being more significant in the dentin than in the enamel because there is a lower concentration of these minerals in the bleached dentin than in the control group (BERGER, 2014;BASTING, 2014).…”

The effect of different biomimetic materials as a remineralization protocol on microhardness and ultramorphology of bleached enamel

“…Although there is little question about their efficacy, the enhancement in tooth color may be at the expense of the enamel structure may be weakened by the bleaching agent. Numerous studies (2)(3)(4)(5)(6) have evaluated the effects of peroxide-containing products on the physical and chemical properties of tooth enamel. However, the research in this area has been controversial (1) .…”

“…However, the research in this area has been controversial (1) . Some studies (2)(3)(4)(5) reported that there was no evident change in enamel microhardness and morphology after bleaching treatment. But others have found calcium loss, alterations in surface morphology, changes in chemical composition and decrease in microhardness of enamel.…”