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| Author(s): |
Flávia de Moraes Italiani
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Bauru. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Odontologia de Bauru (FOB/SDB) |
| Defense date: | 2010-05-28 |
| Examining board members: |
Marilia Afonso Rabelo Buzalaf;
Alberto Carlos Botazzo Delbem;
Ana Carolina Magalhães;
Juliano Pelim Pessan;
Kikue Takebayashi Sassaki
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| Advisor: | Marilia Afonso Rabelo Buzalaf |
| Abstract | |
The aims of this study were to investigate the effect of iron (Fe+2) associated or not to fluoride (F-) on the reduction of bovine enamel and dentin erosion, as well as to develop and evaluate a dentifrice containing Fe+2 to prevent erosion associated to abrasion. Four subprojects were done: (1) In vitro determination of the protective effect of increasing Fe+2 concentrations (0 to 120 mmol/L) associated or not to F- (0 to 4 g/mL) against the dissolution of powdered enamel; (2) In vitro evaluation of the protective effect of 10 mol/L Fe+2 against the mineral dissolution of superficial bovine enamel; (3) Development and in vitro evaluation of fluorided dentifrices containing different Fe+2 concentrations in order to prevent the mineral loss of bovine enamel; and (4) In situ evaluation of the effect of a dentifrice containing Fe+2 and F- on the demineralization of sound or previously eroded bovine enamel and dentin. The response variables were quantification of phosphate loss (colorimetry) and tooth wear (perfilometry, m) for the subprojects 1 and 2, and 3 and 4, respectively. Data were submitted to statistical analyses (p <0.05). In subproject (1), two-way ANOVA and Bonferronis test revealed that solutions containing 1.25, 2.5, 5.0, 10.0, 15.0 and 30.0 mmol/L Fe+2 significantly reduced the dissolution of powdered enamel at 18, 18, 23, 35, 35 and 55%, respectively, in comparison to control (without Fe+2). In the presence of F-, the effect of Fe+2 on the dissolution of enamel was reduced and no synergistic effect between these ions was observed in the tested conditions. In Subproject (2), two-way ANOVA and Bonferronis test showed a significant reduction on surface demineralization of bovine enamel (around 30-40%), when the solution containing Fe+2 at 10 mmol/L was used. In Subproject (3), ANOVA revealed a significant difference among the groups (Placebo, 1,100 g/mL F, Crest®, 1.0 mg/g Fe+2, 2.5 mg/g Fe+2, 5.0 mg/g Fe+2, F- (1, 100 g/mL) + 1,0 mg/g Fe+2, F- (1100 g/mL) + 2,5 mg/g Fe+2 and F- (1,100 g/mL) + 5,0 mg/g Fe+2) (F=4,734, p<0,0001). The lowest wear (0.48±0.24 m) was observed when the dentifrice containing F + Fe was used. In Subproject (4), for sound enamel, two-way ANOVA revealed a significant difference among the dentifrices, (F=21.72, p<0.0001), but not among the conditions (erosion only, erosion + slurry, erosion + abrasion) (F=1.20, p=0.32) or for the interaction of both (F = 1.04, p=0.41). The Bonferronis test revealed that the blocks which received the dentifrice containing Fe+2 and F- presented significantly lesser wear when compared to the blocks submitted to the other dentifrices, which did not differ significantly among each other. As for sound dentin as well as for previously eroded enamel and dentin, the same pattern was obtained but the latter two presented wear values higher than those seen for the sound blocks. (AU) | |