Abstract
BackgroundThis in vitroinvestigation shows how 3.3% H2O2, at different pH-values affects the enamel.Material and MethodsA number of fifteen human premolars were used. The enamel of the coronal half in six of the teeth, were exposed by H2O2. Nine teeth were prepared to enamel powder. The enamel was exposed to 3.3% H2O2, at six different pH-values (pH range 4.5 - 7.0). Analyses of the topography of enamel performed by scanning electron microscope (SEM) and the chemical composition of enamel by X-ray microanalysis (XRMA). X-ray powder diffraction (XRD) analysed the crystallinity in enamel powder.ResultsThe exposure to H2O2 at pH<5.5 resulted in a rougher topography of the enamel, according to the SEM studies. The XRMA analysis revealed a increase in the ratio of Ca:C. Exposure to H2O2 at pH>5.5 resulted in a decrease of O in the exposed enamel, and changes in C:P, Ca:C, Ca:P and Ca:O were observed. The H2O22 did not affect the unit cell parameters, but the signal-to-noise level was increased for slightly acidic or neutral solutions. The unit cell parameters decreased in the acidic solutions.ConclusionsThe exposure to H2O2 at varying pH values affect the enamel with two different mechanisms. One effect is the oxidation of the organic or bioorganic matter in the hydroxyapatite matrix, due to the use of 3.3% H2O2. The other effect is due to the current pH of the H2O2, since the structure of the hydroxyapatite starts to erode when the pH<5.5. Key words:Dental Enamel, Tooth Bleaching Agents, Hydrogen Peroxide, Scanning Electron Microscopy, X-ray diffraction.
Highlights
The mechanism of the hydrogen peroxide is driven by oxidation of the organic or bioorganic substances in enamel and in dentine [1]
The topography of the enamel, using scanning electron microscope (SEM) methods parallel with the analysis of the structure, as well as the crystallinity in enamel exposed to hydrogen peroxide using X-ray powder diffraction (XRD), has not yet been studied to the authors’ knowledge
When the pH-value is less than 5.5 units, the minerals in enamel are removed by dissolution and the individual crystals in the enamel matrix diminish, resulting in an enlargement of the intercrystalline spaces, which is seen in the SEM and XRD studies
Summary
The mechanism of the hydrogen peroxide is driven by oxidation of the organic or bioorganic substances in enamel and in dentine [1]. The effect of whitening products on the structure of enamel has not been thoroughly investigated or determined, when focusing on how enamel is affected by moderately concentrated peroxide in combination with different pH- values. This study is directed toward the analysis of the enamel including the topography of the surface, the chemical content and analysis of the crystallinity, and the structural composition of the enamel, when exposed to hydrogen peroxide at different pH-values (ranging from 4.5 - 7.0). The null-hypothesis used in this study is that the oxidation effect of hydrogen peroxide on enamel, at different pH-values, will be determined independently from the pH-value of the exposing agent This in vitro investigation shows how 3.3% H2O2, at different pH-values affects the enamel. X-ray powder diffraction (XRD) analysed the crystallinity in enamel powder
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
