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OBJECTIVE: The aim of this in vitro study was to evaluate the protective effect against enamel erosion of experimental solutions containing TiF4/NaF and Chitosan compared to a commercial SnCl2/NaF/AmF solution. DESIGN: Bovine enamel samples were divided (n = 15/group) into: (1) commercial solution SnCl2/NaF/AmF (500 ppm F-, positive control); (2) NaF/TiF4 (490 ppm F-); (3) similar to 2 plus 0.5 % chitosan (Ch) (500 mPas), (4) similar to 2 plus 0.5 % chitosan (2000 mPas), (5) negative control (water), (6) 0.5 % chitosan (500 mPas) and (7) 0.5 % chitosan (2000 mPas). The samples were submitted to a pH cycling (0.1 % citric acid, 4 × 90 s/day, interposed by artificial saliva) and daily treatment application (after the last erosive challenge, 1 × 30 s/day) for seven days. After the first day, the surface reflection intensity changes (% rSRI) were measured. After 7 days, the erosive enamel loss was quantified by contact profilometer. The % rSRI and the enamel loss (µm) were compared using ANOVA/Tukey and Kruskal-Wallis/Dunn, respectively (p < 0.05). RESULTS: The solution containing TiF4/NaF plus Ch 500 mPas was the only able to reduce the early erosive demineralization compared to negative control (p = 0.003). However, it did not differ from the other solutions. Enamel samples treated with SnCl2/NaF/AmF presented the lowest median loss value [0.72 (0.18) µm] followed by both TiF4 + Ch [1.24 (0.49) and 1.28 (0.25)]; which significantly differed from the negative control [1.70 (0.27)]. CONCLUSION: The experimental solution containing TiF4/NaF plus chitosan (2000 mPas) has comparable effect to SnCl2/NaF/AmF on the protection against enamel erosion.

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OBJECTIVES: 1. To evaluate the use of fluoridated mouthrinses before or after toothbrushing on erosive tooth wear. 2. To compare the anti-erosive effect of the combination toothpaste and mouthrinse containing fluoride, with or without stannous chloride. DESIGN: Enamel and dentin specimens were randomly distributed into groups (n = 10 of each substrate/group): B-brushing, B + R-brushing + rinsing, and R + B-rinsing + brushing. The treatments were performed using a fluoride toothpaste (BF: 1400 ppm fluoride, as amino fluoride-AmF) combined or not with a fluoride mouthrinse (RF: 250 ppm fluoride, as AmF and sodium fluoride-NaF) or fluoride and stannous toothpaste (BF+Sn: 1400 ppm fluoride, as AmF and NaF, 3500 ppm stannous, as stannous chloride-SnCl2 and 0.5% chitosan) combined or not with fluoride and stannous mouthrinse (RF+Sn: 500 ppm fluoride, as AmF and NaF, 800 ppm stannous, as SnCl2). As control, brushing was performed with artificial saliva (BC). Specimens were submitted to a 5-day erosive-abrasive cycling model. Treatments were performed twice daily. Surface loss (SL) was determined by optical profilometry. Data were analyzed by ANOVA and Games-Howell tests (α = 0.05). RESULTS: For enamel, RF+BF and RF+Sn+BF+Sn presented significantly lower SL than the control, with RF+BF being significantly lower than RF+Sn+BF+Sn. For dentin, BC had the lowest SL, not differing from BF+Sn+RF+Sn, RF+Sn+BF+Sn and BF. Groups RF+BF and BF+RF showed highest SL, not differing from BF+Sn and BF+Sn. CONCLUSIONS: For enamel, the use of a mouthrinse before brushing was able to reduce erosive wear for both fluoride and stannous products. For dentin, the use of stannous-containing products, irrespective of the order of application, presented superior effects.

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This study evaluated the influence of toothbrushing on the antierosive effect of solutions containing sodium fluoride (225 ppm/F), stannous chloride (800 ppm/Sn), sodium linear polyphosphate (2%/LPP), and their combinations, and deionized water as negative control (C). Solutions were tested in a 5-day erosion-remineralization-abrasion cycling model, using enamel and dentin specimens (n = 8). Erosion was performed 6 times/day for 5 min, exposure to the test solutions 3 times/day for 2min, and toothbrushing (or not) with toothpaste slurry 2 times/day for 2 min (45 strokes). Surface loss (SL) was determined by noncontact profilometry. Data were analyzed using three-way ANOVA (α = 0.05). Brushing caused more SL than no brushing for enamel (mean ± SD, in micrometers: 52.7 ± 6.6 and 33.0 ± 4.5, respectively), but not for dentin (28.2 ± 1.9 and 26.6 ± 1.8, respectively). For enamel without brushing, F+LPP+Sn showed the lowest SL (23.8 ± 3.4), followed by F+Sn (30.6 ± 4.9) and F+LPP (31.7 ± 1.7), which did not differ from each other. No differences were found between the other groups and C (37.8 ± 2.1). When brushing, F+LPP+Sn exhibited the lowest SL (36.7 ± 2.4), not differing from F+LPP (39.1 ± 1.8). F, F+Sn and LPP+Sn were similar (46.7 ± 2.9, 42.1 ± 2.8 and 45.3 ± 4.6, respectively) and better than C (52.7 ± 4.3). Sn (55.0 ± 2.4) and LPP (51.0 ± 4.3) did not differ from C. For dentin, neither groups differed from C, regardless of brushing. In conclusion, toothbrushing did not affect the antierosive effect of F+Sn, F+LPP and F+LPP+Sn on enamel, although overall it led to more erosion than nonbrushing. F and LPP+Sn showed a protective effect only under brushing conditions, whereas Sn and LPP did not exhibit any protection. For dentin, neither toothbrushing nor the test solutions influenced the development of erosion.

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Nd:YAG laser and its association with fluoride have been proposed as an option for the prevention of dental erosion. This study evaluated the progression of existing dentin erosive lesions after treatment with different Nd:YAG laser (1064 nm) protocols, associated or not with fluoride. Erosive lesions were created with 1 % citric acid for 10 min in human dentin specimens. They were randomly assigned into eight groups (n = 15): no treatment (control), 1-min application of 2 % sodium fluoride gel (NaF), Nd:YAG1 (Nd:YAG laser irradiation 0.5 W; 50 mJ; ~41.66 J/cm(2); 10 Hz; 40 s; in contact), Nd:YAG2 (0.7 W; 70 mJ; ~62.50 J/cm(2); 10 Hz; 40 s; in contact), Nd:YAG3 (1 W; 100 mJ; ~54,16 J/cm(2); 10 Hz; 40 s; 1 mm unfocused), NaF + Nd:YAG1, NaF + Nd:YAG2, and NaF + Nd:YAG3. After treatment, the specimens were submitted to a 5-day erosion-remineralization cycling model, 6×/day. Dentin surface loss (SL) was evaluated with optical profilometry after the formation of the initial lesion; after treatment; and after days 1, 3, and 5. Data were statistically analyzed (alpha = 0.05). Significant differences were observed among the groups in all testing times (p < 0.001), except after initial lesion formation. Loss of dentin surface was observed after irradiation with all Nd:YAG laser protocols (p < 0.05). The association fluoride and laser did not differ significantly from laser alone. NaF showed the lowest values of SL and Nd:YAG2 and NaF + Nd:YAG2, the highest. Within the limitations of an in vitro study, it was concluded that laser irradiation, according to the parameters used, was not an appropriated approach to prevent dentin erosion progression, even when it was associated with fluoride.

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This study evaluated the progression of enamel erosion after treatment with gels containing sodium fluoride (NaF; 9047 ppm F) and stannous chloride (SnCl2; 3000 ppm Sn), associated or not with Nd:YAG laser irradiation. Sixty enamel specimens were prepared from bovine incisors and protected by a tape, leaving an exposed surface area of 4 × 1 mm. The specimens were immersed in 1 % citric acid (pH = 2.3) for 10 min to create an initial erosion lesion. After, they were randomly divided into six groups: (C) control: gel without active ingredient; (F): NaF gel; (F + Sn): NaF + SnCl2 gel; (laser): Nd:YAG laser irradiation (0.5 W; 50 mJ; ∼41.66 J/cm(2); 10 Hz; 40 s); (F + laser): NaF gel + Nd:YAG; (F + Sn + laser): NaF + SnCl2 gel + Nd:YAG. All gels had pH = 4.5 and were applied for 1 min. Laser irradiation was performed after gel application. The specimens were then submitted to a 5-day erosion-remineralization cycling model using 1 % citric acid (pH = 2.3), six times per day. Enamel surface loss (SL) was analyzed by optical profilometry in the end of the cycling (in µm). Data were analyzed by one-way ANOVA and Holm-Sidak tests (alpha = 0.05). The control and the laser groups presented the highest enamel loss (means ± SD = 53.52 ± 3.65 and 53.30 ± 2.73, respectively), followed by F + Sn (44.76 ± 2.83). The groups F (36.76 ± 2.28), F + laser (36.25 ± 3.59), and F + Sn + laser (39.83 ± 4.62) showed the lowest enamel loss, with no significant difference among them (p > 0.05). In conclusion, NaF by itself or associated with SnCl2 and Nd:YAG laser was able to reduce enamel erosion progression. Nd:YAG laser alone did not show a protective effect.

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Devido à alta prevalência da erosão dental, esse trabalho tem por objetivo avaliar diferentes protocolos do laser de Nd:YAG e flúor na progressão de lesões de erosão em dentina. Para isso, o trabalho foi divido em duas etapas. Na primeira, foram utilizados 120 terceiros molares humanos que tiveram sua dentina exposta e incluída em resina acrílica. Após polimento, as amostras com curvatura de até 0,3 ?m foram selecionadas. Estas ficaram 10 minutos em ácido cítrico 1% (pH 2,3) para formação de lesão de erosão inicial e então, foram divididas em 8 grupos experimentais (n=15): Controle (sem tratamento), Flúor (gel de fluoreto de sódio neutro 2%), Nd:YAG1 (0,5W; 50mJ; ~41,66J/cm2; 10Hz; 40s; em contato), Nd:YAG2 (0,70W; 70mJ; ~62,50J/cm2; 10Hz; 40s; em contato), Nd:YAG3 (1,0W; 100mJ; ~54,16J/cm2; 10Hz; 40s; 1mm desfocado), Flúor+Nd:YAG1, Flúor+Nd:YAG2 e Flúor+Nd:YAG3. Para verificar a perda de superfície ocorrida, foram feitas leituras em perfilômetro óptico nos seguintes tempos: após formação da lesão inicial, logo após tratamentos e após 1o, 3o e 5o dias de ciclagem erosiva. Para a segunda etapa, foram utilizadas 93 dentinas extraídas de terceiros molares humanos, as quais também foram incluídas em resina acrílica e polidas. Das amostras obtidas, foram selecionadas 60 com curvatura adequada para as análises perfilométricas, nos mesmos tempos descritos anteriormente. As outras 33 amostras foram utilizadas para análise em microscopia eletrônica de varredura, nos tempos pós-lesão inicial, pós-tratamento e ao final dos cinco dias de ciclagem erosiva. Após formação da lesão inicial, elas foram divididas em 6 grupos experimentais: Controle (nenhum tratamento),

Flúor (gel de fluoreto de sódio neutro 2%), Nd:YAG1 (0,5W; 50mJ; ~26,6J/cm2; 10Hz; 40s; 1mm desfocado), Nd:YAG2 (0,7W; 70mJ; ~37,5J/cm2; 10Hz; 40s; 1mm desfocado), Flúor+Nd:YAG1 e Flúor+Nd:YAG2. Os dados resultantes das análises perfilométricas foram submetidos à análise estatística, sendo as duas etapas independentes. Significância estatística foi de 5%. Na primeira etapa, os grupos apresentaram diferença significante em todos os tempos analisados (p<0,001), exceto após lesão inicial. Houve perda superficial após irradiação com todos os protocolos do laser de Nd:YAG. A associação do flúor com o laser não diferiu significativamente do laser isoladamente. O grupo Flúor apresentou os menores valore de perda de superfície e os grupos Nd:YAG2 e Flúor+Nd:YAG2 apresentaram os maiores valores, não havendo diferença entre eles. Na segunda etapa, os grupos também apresentaram diferença significante em todos os tempos (p=0,001). Os grupos Flúor e Flúor+Nd:YAG1, após o primeiro dia de ciclagem, tiveram menor perda de superfície que os outros grupos. Nos outros tempos, os grupos Flúor, Flúor+Nd:YAG1 e Flúor+Nd:YAG2, tiveram menor perda de superfície que o grupo Controle e este não foi diferente dos grupos apenas irradiados com o laser, independente do protocolo. As micrografias foram analisadas qualitativamente e mostraram que o laser nos parâmetros utilizados não foi capaz de obliterar os túbulos dentinários, porém, reduziu o diâmetro dos mesmos. Dentro das limitações de um estudo in vitro, pode-se concluir que o flúor tem papel protetor na progressão da erosão dental e que o laser de Nd:YAG, quando utilizado dentro dos parâmetros adequados, pode ser eficaz no tratamento da erosão dental.

Due to the high prevalence of dental erosion, this study aimed to evaluate the progression of dentin erosion after treatment with different protocols of the Nd:YAG laser and fluoride. Thus, this study was divided into two phases. In the first phase, 120 human third molars had their dentin exposed and embedded in acrylic resin. After polishing, specimens with curvature of maximum 0.3 ?m were selected. They were immersed in 1% citric acid (pH 2.3) for 10 minutes to form initial erosion lesion and then they were divided into 8 experimental groups (n=15): Control (no treatment), Fluoride (neutral sodium fluoride gel 2%), Nd:YAG1 (0,5W; 50mJ; ~41,66J/cm2; 10Hz; 40s; contact), Nd:YAG2 (0,70W; 70mJ; ~62,50J/cm2; 10Hz; 40s; contact), Nd:YAG3 (1,0W; 100mJ; ~54,16J/cm2; 10Hz; 40s; 1mm defocused), Fluoride+Nd:YAG1, Fluoride+Nd:YAG2 and Fluoride+Nd:YAG3. Surface loss was evaluated by optical profilometry after initial lesion, right after treatments, and after 1st, 3rd and 5th erosion cycling days. For the second phase, 93 dentin specimens were obtained from human third molars. They were also embedded in acrylic resin and polished. From those specimens, 60 with adequate curvature were selected for the profilometer analysis, which were at the same time points described before. The other 33 specimens were analyzed by scanning electron microscopy, after formation of initial lesion, after treatments and at the end of the five days of erosive cycling. After formation of initial lesion, specimens were divided in six groups: Control (no treatment), Fluoride (neutral sodium fluoride gel 2%), Nd:YAG1 (0,5W; 50mJ; ~26,6J/cm2; 10Hz; 40s; 1mm defocused), Nd:YAG2 (0,7W; 70mJ; ~37,5J/cm2; 10Hz; 40s; 1mm defocused)...

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