The effect of a 10% carbamide peroxide bleaching agent on the phosphate concentration of tooth enamel assessed by Raman spectroscopy

Abstract

The study assessed changes in phosphate concentrations of surface enamel treated with a proprietary bleaching agent ('PEROXIDE') containing 10% carbamide peroxide over a 28-day period using Raman spectroscopy. Six non-carious human molar teeth (age range 12-21 years), extracted for orthodontic reasons, were used. From the enamel face of each half tooth, a near flat enamel section, approximately 2 x 2 mm, was cut, providing 12 specimens. Each specimen was treated with 10% carbamide peroxide for 8 h day(-1) for 28 consecutive days, with Raman spectra being obtained prior to bleaching and after 7, 14, 21 and 28 days. Raman spectra were acquired on a confocal LabRam 300 spectrometer fitted with an Olympus B microscope (Olympus, Middlesex, UK). The difference in the maximum peak values for phosphate group concentrations were tested using the Friedman test (non-parametric anova) and Dunn's multiple comparison test. An intense broad band at 980 cm(-1), characteristic of phosphate groupings, was always observed. At 7 and 14 days, and again at 28 days, there was a significant decrease in the phosphate group concentration compared with base-line measurements (P < 0.05) but not at 21 days (P > 0.05). Ideally, bleaching should not be continued to a point where surface enamel is lost, and the present study suggests that a regime using 10% carbamide peroxide should not extend to 7 days.

Surface pre-conditioning with bioactive glass air-abrasion can enhance enamel white spot lesion remineralization

“…The phosphate peak at 959 cm −1 represented the hydroxyapatite (HA) of enamel, and its intensity relates to the amount of HA mineral within the scanned area [41,42]. The C O Raman peak of hydroxycarbonate apatite (HCA) layer formed on the reacted BAG particles at 1085 cm −1 clearly detectable during HCA formation [29].…”

Remineralization of bleached enamel with novel nutraceutical agents: An in vitro study

“…[11] Raman spectroscopic study showed that exposure to 10% CP for more than 7 days resulted in a signifi cant decrease in phosphate concentration in the bleached enamel. [5] On the contrary, a study did not report any mechanical, morphologic, or chemical changes following vital bleaching with CP. [12] Hence, the eff ect of bleaching on dental enamel is not yet clear and is still a controversial subject.…”

“…From dentine hydrogen peroxide reaches the pulp, where it directly activates A -δ nerves which thereby results in pain. [5] Thus, the surface morphological changes may contribute to the sensitivity associated with bleaching.…”

Comparison of Nd:YAG and Diode Laser Irradiation During Intracoronal Bleaching with Sodium Perborate: Color and Raman Spectroscopy Analysis

“…The Raman spectra of enamel represent the intensity of the signal according to the frequency, and allow comparative and quantitative analysis. 26 Some studies used Raman spectroscopy and scanning electron or atomic force microscopy together to analyze the structure of the enamel surface after tooth bleaching. 13,14 Although these studies investigated vital tooth bleaching, intracoronal bleaching was studied in the present study.…”