Effects of new formulas of bleaching gel and fluoride application on enamel microhardness: An in vitro study

Juliana da Costa, R. F. Mazur

Research output: Contribution to journalArticle

33 Scopus citations


This in vitro study evaluated the new formulas of bleaching products and the effect of subsequent applications of fluoride on the hardness of enamel during and after tooth bleaching. The crowns of 60 extracted intact human molars were sectioned longitudinally; the buccal part was embedded in acrylic resin, the occlusal part was ground flat, exposing enamel and dentin, and then polished. Baseline Knoop microhardness (KHN) of enamel was determined. The specimens were then randomly divided into six groups of 10 specimens, and each group was assigned to a specific 10% carbamide peroxide (CP) bleaching agent. A: Opalescence, B: Opalescence PF (3% potassium nitrate and 0.11% fluoride), C: Nite White Excel 3 (ACP), D: Opalescence + F (acidulated phosphate fluoride 1.23%), E: Opalescence PF + F, F: Nite White Excel 3 + F. The teeth were bleached for eight hours; after each procedure, the specimens were stored in artificial saliva at 37°C. Immediately after day 21 of bleaching, the specimens in groups D, E and F received fluoride 1.23% for five minutes. KHN tests were performed before (baseline=control), during (14, 21) and two weeks (35 days) after the bleaching procedure and were statistically compared using ANOVA/Tukey's t-test (a

Original languageEnglish (US)
Pages (from-to)589-594
Number of pages6
JournalOperative Dentistry
Issue number6
Publication statusPublished - Nov 2007


ASJC Scopus subject areas

  • Dentistry(all)

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