Objectives: Aim of the study was to evaluate enamel fluoride acquisition after application of fluoridated carbamide peroxide (CP) gels. Methods: Twenty-two bovine incisors were equally distributed among two groups (1 and 2). From each tooth, three enamel specimens were prepared. The three samples of each tooth were covered with three different experimental 10% CP gels (Incos, Nieder-Olm, Germany) 4 h (group 1) and 8 h (group 2), respectively. Formulations of gels (A-C) were as follows: A (0.5% fluoride as NaF, pH 5.7), B (0.5% F, pH 7.0), and C (no F, pH 7.0) which served as control. Subsequently, KOH-soluble [µg/cm2] and structurally bound fluoride [µg/cm3] was assessed in all specimens. KOH-soluble fluoride (KOH-s-F) was determined at the enamel surface, structurally bound fluoride (struct-b-F) was evaluated in two successive layers of 50 µm each. The data were statistically analyzed by ANOVA (p £ 0.05). Results: The following values (mean ± S.D.) were obtained:
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group 1 (4h) |
group 2 (8h) |
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struct-b-F |
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struct-b-F |
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0-50 µm |
51-100 µm |
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0-50 µm |
51-100 µm |
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gel A |
8.1 ± 1.8 |
277.4 ± 135.1 |
176.2 ± 99.2 |
14.4 ± 9.7 |
319.4 ± 123.5 A |
221.0 ± 87.7 A |
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gel B |
2.3 ± 1.3 |
199.9 ± 111.7 |
129.9 ± 65.8 |
7.4 ± 5.4 |
309.9 ± 138.7 A |
252.8 ± 110.6 A |
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gel C |
0.3 ± 0.2 |
111.8 ± 99.4 |
70.6 ± 30.9 |
0.4 ± 0.2 |
108.4 ± 71.6 |
109.4 ± 110.5 |
Values with same superscript letter in one column were not significantly different.
Conclusion: Application of fluoridated 10% carbamide peroxide gel leads to acquisition of fluoride in enamel with higher deposition of KOH-soluble fluoride for an acidic than for a neutral gel.