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To compare in vitro the effect of a toothpaste containing fluoride (F), calcium silicate (CaSi) and sodium phosphate salts to conventional toothpaste (NaF) on human enamel specimens submitted to erosive and abrasive challenges. Methods: 48 sound and 48 enamel samples pre-treated with 1% citric acid were divided into 4 groups (n ¼ 12): Group 1-Non-fluoride toothpaste; Group 2-NaF toothpaste (1450 ppmF); Group 3-CaSi toothpaste (1450 ppmF; MFP); Group 4-Erosion only. The samples were subjected to pH cycling (3 cycles/day; 90s; 1% citric acid, pH 3.6) and to abrasion for 7 days. After the 1 st and the last cycle, they were submitted to abrasion (15s, 1.5N load), using a brushing machine, soft toothbrush and toothpaste slurry (1:3; 15ml/sample) and then immersed in the slurry for 45s. Samples were immersed in artificial saliva between the challenges. Enamel loss was evaluated using profilometry on days 3 and 7. Data were analysed by ANOVA and Tukey's test (p < 0.05). Results: For sound enamel at baseline, mean (AESD) enamel loss (μm) for groups 1-4 on day 3 was 2.15 AE 0.35 a , 1.20 AE 0.22 b , 0.95 AE 0.19 b and 1.98 AE 0.32 a ; on day 7 was 3.05 AE 0.40 a , 2.07 AE 0.32 b , 1.36 AE 0.33 c and 3.69 AE 0.27 d respectively. For acid-softened enamel at baseline, enamel loss on day 3 was 3.16 AE 0.19 a , 2.17 AE 0.14 b , 1.70 AE 0.11 c and 3.04 AE 0.19 a ; on day 7 was 3.92 AE 0.25 a , 3.07 AE 0.13 b , 2.09 AE 0.15 c and 3.87 AE 0.25 a respectively. Conclusions: Both F toothpastes led to significantly higher enamel protection from short-term erosion and abrasion in comparison to the non-F toothpaste and erosion only. In the longer term, CaSi toothpaste conferred significantly higher protection than NaF toothpaste. Clinical significance: The results showed that for the longer term the CaSi toothpaste provided significantly higher protection than the NaF toothpaste, which indicates a good potential of the former to help prevent erosive tooth wear.

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Fluoride (F) can induce changes in the expression of several liver proteins, most of them localized in the mitochondria and its effect is dose-and time-dependent. This study analyzed the effect of distinct F concentrations and exposure periods on the mitochondrial activity of complex I-III and II-III in the liver. Thirty-six 21-day-old male Wistar rats were divided into 2 groups (n ¼ 18) according to the duration of the treatment (20 or 60 days). They were subdivided into 3 subgroups (n ¼ 6) according to the concentration of F (0 mg/L, 15 mg/L or 50 mg/L). After the experimental periods, the animals were anesthetized, liver mitochondria were isolated and stored for activity analyses. The determination of complexes II-III and I-III was based on the reduction of cytochrome c 3þ to cytochrome c 2þ performed spectrophotometrically. Bioinformatics analyses were performed using data from a previous study (Pereira et al., 2018). The mitochondrial complex I-III was significantly activated in the groups treated with 50 mgF/L for 20 days and 15 mgF/L for 60 days. The complex II-III was significantly reduced in the group treated with the higher F dose for 60 days. The networks indicated more changes in mitochondrial proteins in the group treated with the higher dose for 20 days; the reduction is probably linked to the activation of the complex I-III. The reduction in the complex II-III upon exposure to the higher F dose in the long term might be part of an adaptative mechanism of the body to counteract the deleterious effects of this ion on the energy metabolism.

We compared the parameters related to glucose homeostasis, and liver and muscle proteomes in fluorosis-susceptible (A/J; S) and fluorosis-resistant (129P3/J; R) mice in response to fluoride (F) exposure and exercise. Ninety male mice (45 R-mice and 45 S-mice) were randomized into three groups: (SI; RI) No-F, No-Exercise, (SII; RII) 50 ppm F, No-Exercise, (SIII; RIII) 50 ppm F, Exercise. Overall, mean F concentrations in the plasma and femur were significantly higher in R-mice compared with S-mice. In R-mice, exercise resulted in an increase in F accumulation in the femur. In S-mice, the mean plasma glucose level was significantly higher in Group II compared with Groups I and III. There was an increase in liver proteins involved in energy flux and antioxidant enzymes in non-exercise groups (I, II) of S-mice in comparison with the corresponding groups of R-mice. The results also showed a decrease in muscle protein expression in Group I S-mice compared with their R-mice counterparts. In conclusion, the findings suggest an increased state of oxidative stress in fluorosis-susceptible mice that might be exacerbated by the treatment with F. In addition, fluorosis-susceptible mice have plasma glucose levels higher than fluorosis-resistant mice on exposure to F, and this is not affected by exercise.

The effect of solutions containing a statherin-derived peptide (Stn15pSpS) on the protection against enamel erosion in vitro was evaluated. Bovine enamel specimens were divided into 4 groups (n = 15/group): 1) Deionized water (negative control), 2) Elmex Erosion Protection™ (positive control), 3) 1.88 × 10-5 M Stn15pSpS and 4) 3.76 × 10-5 M Stn15pSpS. The solutions were applied on the specimens for 1 min. Stimulated saliva was collected from 3 donors and used to form a 2-h acquired pellicle on the specimens. Then, the specimens were submitted to an erosive pH-cycling protocol 4 times/day, for 7 days (0.01 M HCl pH 2.0/45 s, artificial saliva/2 h, and artificial saliva overnight). The solutions were applied again during pH cycling, 2 times/day for 1 min after the first and last erosive challenges. Enamel loss (µm) was assessed by contact profilometry. Data were analyzed by Kruskal-Wallis and Dunn's test (p < 0.05). The best protection against erosion was conferred by Elmex Erosion Protection that significantly differed from all the other treatments, followed by the solutions containing Stn15pSpS, regardless of the concentration. However, 3.76 × 10-5 M Stn15pSpS did not differ from the negative control. The solution containing the lower concentration of Stn15pSpS protected against erosion in vitro, which should be confirmed using protocols that more closely resemble the clinical condition.

Dedico essa dissertação de mestrado à minha família e amigos:A minha mãe MÃE, muito obrigada por todo apoio, toda ajuda e todo suporte durante a minha vida, sei que não foi fácil chegar até aqui, mas com você sempre ao meu lado eu consegui ir até o final. Ao meu pai e sua esposaMuito obrigada Pai e Leila, mesmo longe vocês tentam estar o mais próximo possível para me ajudar e estar sempre presente, e a presença de vocês na minha vida é essencial, porque vocês são meu alicerce. Aos meus irmãos Tatiane, Abner e ArthurVocês são a razão do meu viver, trazem alegria, felicidade e muito amor para os meus dias, sem o apoio e carinho de vocês não teria chegado até aqui. Ao meu MaridoEu sei que sem você eu não seria nada, porque você me completa. Muito obrigada por todo amor e incentivo durante esses anos, não foi fácil, passamos muitas coisas, mas sempre superamos tudo, e ao seu lado eu me sinto confiante para alcançar cada vez mais nossos sonhos juntos. Aos amigos do Laboratório de BioquímicaEu sei que sem vocês eu não teria chegado até aqui, muito obrigada por todas as risadas, choros, desesperos e também todo apoio e incentivo para nunca desistir, mas sempre acreditar que no final tudo já deu certo.

Fluoride (F) has been widely used to control dental caries, and studies suggest beneficial effects against diabetes when a low dose of F is added to the drinking water (10 mgF/L). Objectives This study evaluated metabolic changes in pancreatic islets of NOD mice exposed to low doses of F and the main pathways altered by the treatment. Methodology In total, 42 female NOD mice were randomly divided into two groups, considering the concentration of F administered in the drinking water for 14 weeks: 0 or 10 mgF/L. After the experimental period, the pancreas was collected for morphological and immunohistochemical analysis, and the islets for proteomic analysis. Results In the morphological and immunohistochemical analysis, no significant differences were found in the percentage of cells labelled for insulin, glucagon, and acetylated histone H3, although the treated group had higher percentages than the control group. Moreover, no significant differences were found for the mean percentages of pancreatic areas occupied by islets and for the pancreatic inflammatory infiltrate between the control and treated groups. Proteomic analysis showed large increases in histones H3 and, to a lesser extent, in histone acetyltransferases, concomitant with a decrease in enzymes involved in the formation of acetyl-CoA, besides many changes in proteins involved in several metabolic pathways, especially energy metabolism. The conjunction analysis of these data showed an attempt by the organism to maintain protein synthesis in the islets, even with the dramatic changes in energy metabolism. Conclusion Our data suggests epigenetic alterations in the islets of NOD mice exposed to F levels comparable to those found in public supply water consumed by humans.