Study of the effects of unsupervised over‐the counter whitening products on dental enamel using μ‐Raman and μ‐EDXRF spectroscopies

Abstract

The purpose of this in vitro study was to assess whether the mineralization degree and elemental content in tooth enamel are altered when bleaching the teeth with two different over-the-counter bleaching gels, exceeding the recommendations of the manufacturer. In order to perform this evaluation, 12 healthy teeth were used, six samples were treated with Teeth Whitening Home Kit, and the other six samples were treated with WHITE! (Bingo-UK) bought in online shopping sites, for the period of 39 days. The pH of each product and the elemental content of each sample, before and after, were obtained by energy dispersive X-ray spectrometry and phosphate (PO 4 3-) profile was evaluated with Raman spectroscopy. Data was analyzed accordingly to a preestablished plan with a mixed-model ANOVA for repeated measures, significance was set at 5%. Both products were markedly acidic and below enamel critical level of 5.5. Moreover, seven days after treatment, demineralization was significant, wherein at the end of the study the degree of demineralization seems to be permanent.

Raman spectroscopy analysis of dental enamel treated with whitening product – Influence of saliva in the remineralization

“…Raman spectroscopy has been used to study the changes in the symmetric stretching mode of the tetrahedral phosphate (PO 4 3− ) group which is representative of the mineral phase (carbonated hydroxyapatite) in teeth. This has been done with teeth treated with different concentrations of bleaching agents as well as different storing methodologies for the specimens [4][5][6][7][8].…”

Evaluation of enamel demineralization and fluorine uptake caused by gustatory stimulants of salivary secretion (GSSS) using Raman spectroscopy and proton induced gamma‐ray emission (PIGE)

“…In fact, in the carry out protocols (Figure ), the enamel samples were only immersed in solution with pH below the demineralizing pH of Hydroxyapatite (5.5) for 4 min and for 8 min (for Xeros™ and SST®, respectively) at a time, being most of the time immersed in saliva to recover. Moreover, previous studies with continuous acidic action on human enamel only determined significant decrease in mineralization after 1 week of treatment when using products with much lower pH (pH = 3), otherwise, no effective demineralization was seen …”

“…Several studies demonstrate the decrease in pH with the administration of GSSS; however, there are no further evidences that demineralization of dental enamel by these agents occurred. Raman spectroscopy is an established spectroscopic technique in the evaluation of the enamel's chemical composition modification due to demineralizing agents such as acidic beverages and whitening products used accordingly to manufacturer or in an abusive manner . The analysis of the PO 4 3− symmetric stretching mode at approximately 959 cm −1 and its polarization anisotropy have also been demonstrated as being sensitive markers of demineralization, namely, of early caries detection .…”

Recent advances in linear and non‐linear Raman spectroscopy. Part XI

“…Castro and co‐workers published a study of the effects of unsupervised over‐the‐counter whitening products on dental enamel using μ‐Raman and μ‐EDXRF spectroscopies. The purpose of their in vitro study was to assess whether the mineralization degree and elemental content in tooth enamel are altered when bleaching the teeth with two different over‐the‐counter bleaching gels, thereby possibly exceeding the recommendations of the manufacturer . Cloe et al determined lipid organization and stratum corneum thickness in vivo in human skin by analyzing the lipid‐keratin peak (2,820–3,030 cm −1 ) using confocal Raman microscopy.…”