title: 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.
authors: The University of Edinburgh, Edinburgh, UK. ariosantini@hotmail.com
authors: Ario
authors: A
authors: Santini
authors: Colin R
authors: CR
authors: Pulham
authors: Ahmed
authors: A
authors: Rajab
authors: Richard
authors: R
authors: Ibbetson
mesh_terms: D000293:Adolescent; D000328:Adult; D000077463:Carbamide Peroxide; D002648:Child; D003743:Dental Enamel / Q000737:chemistry / Q000187:drug effects*; D004338:Drug Combinations; D006801:Humans; D008963:Molar; D016877:Oxidants / Q000009:adverse effects*; D010545:Peroxides / Q000009:adverse effects*; D010710:Phosphates / Q000032:analysis*; D013059:Spectrum Analysis, Raman; D018709:Statistics, Nonparametric; D013997:Time Factors; D014073:Tooth Bleaching / Q000009:adverse effects*; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives*
chemical_list: D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D010710:Phosphates; D000077463:Carbamide Peroxide; D014508:Urea