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The objective of this in vitro study was to evaluate the influence of remineralizing agents on the surface roughness of eroded tooth enamel. Forty incisive bovines were selected and sectioned to obtain specimens of 4mm X 4mm, resulting in a surface area of 16,00mm², with a thickness of 2.50mm. The specimens were immersed in lemon juice, twice a day, over 5 days, and randomly divided into the following 4 groups: G1 = No treatment; G2 = 1.23% APF; G3 = Fluoride Varnish 5% and G4 = Regenerated. The surface roughness of the specimens was analyzed by means of confocal laser scanning microscopy. The obtained data were submitted to ANOVA after attend the homogeneity (Levene´s) and normality tests (Kolmogorov-Smirnov). All tests were statistically significant at 5% (α=0.05). The results showed that there was no statistically significant difference on the enamel roughness surface area between groups in the experimental region and the founded values were higher at the experimental when compared to the control region, however, without differences between the groups in each region. It was concluded that the remineralizing agents were not able to reduce the surface roughness of the studied groups. Keywords: Tooth Erosion. Dental Enamel. Fluorine. Tooth Remineralization. Resumo O objetivo deste estudo in vitro foi avaliar a influência de agentes remineralizantes na rugosidade da superficial do esmalte dental erodido. Quarenta bovinos incisivos foram selecionados e seccionados para obter espécimes de 4 mm x 4 mm, resultando em uma área superficial de 16,00 mm², com espessura de 2,50 mm. As amostras foram imersas em suco de limão, duas vezes ao dia, durante 5 dias, e divididas aleatoriamente nos 4 grupos seguintes: G1 = Sem tratamento; G2 = Flúor gel 1,23%; G3 = Verniz fluoretado 5% e G4 =Regenerate. A rugosidade superficial das amostras foi analisada por microscopia confocal de varredura a laser. Os dados obtidos foram submetidos à ANOVA após os testes de homogeneidade (Levene) e normalidade (Kolmogorov-Smirnov). Todos os testes foram estatisticamente significantes a 5% (α = 0,05). Os resultados mostraram que não houve diferença estatisticamente significante na rugosidade de área do esmalte entre os grupos na região experimental e os valores encontrados foram maiores na experimental quando comparados à região controle, no entanto, sem diferenças entre os grupos em cada região. Concluiu-se que os remineralizantes não foram capazes de reduzir a rugosidade da superfície dos grupos estudados. Palavras-chave: Erosão Dentária. Esmalte dentário. Flúor. Remineralização Dentária.

The objective of this in vitro study was to evaluate the influence of the Er,Cr:YSGG laser associated or not to a desensitizing agent in the treatment of erosive lesions. Forty specimens with dimensions of 4mm x 4mm and 3mm thickness were divided into 4 groups (n = 10): G1- no treatment; G2- 5% fluoride varnish; G3- Er,Cr: YSGG; G4 - fluoride varnish + laser. The specimens were immersed in erosive drink 3 times a day for 1 minute with an average interval of 2 hours between cycles for a period of 10 days. The treatments were performed according to the groups and the surface roughness and the wear profile were analyzed by scanning confocal microscopy. The normality (Kolmogorov-Smirnov) and homogeneity (Levene's) of the tests were evaluated. After these analyzes, the surface roughness data were submitted to the statistical analysis of Variance Analysis (ANOVA). All tests adopted a significance level of 5% (α = 0.05). At the representative images of the wear profile, the morphology of bovine dental enamel in its control and eroded areas were compared and qualitatively discussed. As regard surface roughness, there was no statistically significant difference between the groups. The qualitative analysis of the loss of volume showed that all experimental groups showed significant superficial morphology differences. Considering the limitations of an in vitro study, it can be concluded that the treatments performed were not able to treat dental erosion satisfactorily, indicating the need for more treatment sessions. Keywords: Tooth Erosion. Dental Enamel. Fluoride. YSGG Laser. ResumoO objetivo desse estudo in vitro foi avaliar a influência do laser Er,Cr:YSGG associado ou não a um agente dessensibilizante no tratamento de lesões erosivas. Foram confeccionados 40 espécimes com dimensões de 4mm x 4mm e 3mm de espessura, divididos em 4 grupos (n=10): G1- nenhum tratamento; G2- verniz fluoretado 5%; G3- aplicação do laser Er,Cr:YSGG; G4- verniz fluoretado + laser. Os espécimes foram imersos em bebida erosiva, 3 vezes por dia, durante 1 minuto, com intervalo médio de 2 horas entre os ciclos, por um período de 10 dias. Os tratamentos foram realizados de acordo com os grupos e que foram analisados a rugosidade superficial e o perfil de desgaste por meio de microscopia confocal de varredura. Avaliou-se a normalidade (Kolmogorov-Smirnov) e homogeneidade (Levene’s) dos dados. Após estas análises, os dados de rugosidade superficial foram submetidos ao teste estatístico de Análise de Variância (ANOVA). Todos os testes adotaram nível de significância de 5% (α=0,05). Através da obtenção das imagens representativas do perfil desgaste, a morfologia do esmalte dental bovino em suas áreas controle e erodida foram comparadas e qualitativamente discutidas. Quanto à rugosidade superficial, não houve diferença estatisticamente significativa entre os grupos. A análise qualitativa da perda de volume mostrou que todos os grupos experimentais apresentaram diferenças significativas na morfologia superficial. Considerando as limitações de um estudo in vitro pode-se concluir que os tratamentos realizados não foram capazes de tratar a erosão dentária de forma satisfatória, indicando a necessidade de mais sessões de tratamento. Palavras-chave: Erosão dentária. Esmalte dental. Flúor. Laser de YSGG.

Objetivo: Avaliar a ação do ácido clorídrico gasoso sobre o esmalte humano e bovino e comparar o padrão de desmineralização desses substratos expostos ao agente erosivo gasoso. Métodos: Oito espécimes de esmalte bovino e oito de esmalte humano foram obtidos (4 × 4 × 2 mm), metade da superfície foi protegida com resina composta e a outra metade exposta ao ácido clorídrico gasoso (gHCl), pH 2 a 37 °C, por 3 min, 8 vezes ao dia, durante 12 dias, e em intervalos os espécimes foram mantidos em saliva artificial. Os espécimes foram analisados quanto ao perfil de desgaste, rugosidade superficial e microdureza (antes e após a exposição ao ácido). Os dados foram analisados estatisticamente por ANOVA de uma via. Resultados: Os dados não mostraram diferença significativa entre o esmalte bovino e humano para todas as propriedades analisadas – microdureza (98,1 ± 5,2, 96,9 ± 4,8), perfil de desgaste (11,5 ± 2,8, 11,4 ± 3,6) e rugosidade (2,6 ± 0,3, 3,3 ± 0,3), respectivamente. Nas imagens, observou-se que gHCl pode causar erosão do esmalte em ambos os grupos. Conclusão: O ácido clorídrico gasoso causa erosão do esmalte de forma semelhante em bovinos e humanos. Objective: To evaluate the action of gaseous hydrochloric acid on human and bovine enamel and compare the demineralization pattern of these substrates exposed to the gaseous erosive agent. Methods: Eight bovine enamel and eight human enamel specimens were obtained (4 × 4 × 2 mm), half surface was protected with composite resin and the other half was exposed to gaseous hydrochloric acid (gHCl), pH 2 at 37 °C, for 3 min, 8 times a day, for 12 days, and in intervals the specimens were maintained in artificial saliva. The specimens were analyzed according to wear profile, surface roughness and microhardness (before and after acid exposition). Data were statistically analyzed by one-way ANOVA. Results: Data showed no significant difference between bovine and human enamel for all properties analyzed – microhardness (98.1 ± 5.2, 96.9 ± 4.8), wear profile (11.5 ± 2.8, 11.4 ± 3.6) and roughness (2.6 ± 0.3, 3.3 ± 0.3), respectively. In images, we observed that gHCl could cause enamel erosion in both groups. Conclusion: Gaseous hydrochloric acid causes similar enamel erosion on bovine and humans.

Aim: The objective of this study was to evaluate the effects of solutions on the color stability of nanohybrid composite resins. Methods: The experimental sample consisted of 90 composite specimens (Beautifil II; Z350XT; Premisa), divided into three subgroups (n=10) according to the solutions (matte tea; lemon flavor isotonic drink; artificial saliva). The specimens were immersed in the solutions (5 mL/specimen) while stirring for 5 minutes, four times a day, with 1-hour intervals, repeated for 15 days. The color of the specimens was analyzed before (baseline) and after the 15th day of cycling using the CIELAB system. Data were analyzed using the two-way analysis of variance (ANOVA) and Tukey’s test (α=5%). Results: Different behaviors were observed among resins. Beautifil II presented the highest color change (∆E=4.18) and less color stability, statistically different from the others (p

The aim of this study was to evaluate color change, mineral composition and topography of the enamel after the pre-treatment with non-thermal atmospheric plasma (NTAP) followed by 38% hydrogen peroxide (HP) bleaching. Buccal enamel of bovine incisors teeth was stained with black tea solution and then divided into five groups (n = 12), according to the plasma application time: PL1 (one minute) or PL2 (2 min) and number of HP applications: HP1 (one) and HP3 (three). The following groups were investigated: HP3, PL1+HP1, PL1+HP3, PL2+HP1 and PL2+HP3. Four color measurements: initial (untreated), after staining and after bleaching (first and second sessions), were performed using an intraoral spectrophotometer (Vita Easyshade). Energy Dispersive X-ray Spectroscopy (EDX) was used to analyze the mineral composition of the enamel before and after two bleaching sessions. Laser confocal microscopy was used to analyze the enamel topography. The pre-treatment with NTAP did not improve the whitening results. The use of NTAP preserves the concentration of calcium and phosphorus, only HP3 group experimented a significant decrease in the mineral concentration. All the bleached groups, with or without NTAP treatment increased their enamel roughness. The application of NTAP did not influence the color change, but it was important to maintain the mineral composition of bleached teeth. All the groups increased their roughness level.

The longevity of a composite resin restoration is constantly being sought in the field of dentistry. The matrix metalloproteinases (MMPs) and cysteine cathepsins (CCs) in the dentin matrix when activated participate in the degradation of collagen fibrils and extracellular components. The preservation of the structural integrity of collagen and the matrix maintains the mechanical properties, chemical stability and resistance to degradation of resin-dentin bonded interface, contributing to restoration durability. Thus, it is of fundamental importance to employ methods and / or agents that promote the inactivation of MMPs and CCs to improve the chemical stability of the adhesive interface. So, several crosslinking agents have been studied (natural and synthetic), however it is observed that chitosan and proanthocyanidin show reliable results and both promote protease inactivation and provide better collagen web resistance, and thus increase the longevity of the restoration procedure.

This in vitro study evaluated the influence of the Er,Cr:YSGG laser, associated or not to desensitizing agents, in the prevention of acid erosion in bovine root dentin. Eighty dentin specimens were selected and divided into eight groups (n = 10): G1: negative control; G2: positive control (5% fluoride varnish-FV); G3: Er,Cr:YSGG laser; G4: FV + laser; G5: 3% potassium oxalate; G6: 3% potassium oxalate + laser; G7: biphasic calcium silicate/phosphate gel (gel); G8: gel + laser. Laser parameters: 0.5 W, 6.25 J/cm2 at 1-mm distance. The erosive drink used was a cola soft-drink (pH = 2.42 at 4 °C), lasting 5 min, twice a day, with 6-h intervals between the challenges, during 14 days. Kolmogorov-Smirnov and Levene’s tests were satisfied. The surface roughness data were submitted to ANOVA and Tukey post hoc tests. For the wear profile, Kruskal-Wallis and Dunn post hoc tests were used. Afterwards, the Spearman correlation test was performed. All statistical tests assumed a significance level of 5% (α = 0.05). G1 presented the highest surface roughness value after the erosive challenge (3.586 μm2 ± 0.205 μm2) and the G7 presented the lowest surface roughness value after the erosive challenge (1.071 μm2 ± 0.180 μm2). For the lost volume, G4 presented the lowest percentage (9.7% ± 0.9%), while G1 had the highest percentage (41.8% ± 2.5%), both with p

This study aims to evaluate how casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) associated with Nd:YAG or Diode laser affects dentin exposed to hydrochloric acid (HCl) with or without tooth brushing.One hundred and sixty human root dentin blocks were selected after they were initially eroded with liquid HCl (pH 1.2) 3x for one day. The blocks were divided into the following groups: G1- liquid HCl (HCl-l), G2- HCl-l + brushing, G3- gaseous HCl (HCl-g), and G4- HCl-g + brushing. Each group was randomly assigned to the following treatments (n = 10): A) Control (no treatment), B) CPP-ACP, C) CPP-ACP associated with Nd:YAG laser (λ = 1064 nm) (40 mJ, 10 Hz, 0.4 W, 15 s), and D) CPP-ACP associated with Diode laser (λ = 980 nm) (0.5 W, 200 μs, 15 s). The treatment with CPP-ACP (G2, G3 and G4) was applied on the dentine surface for 5 min. Erosion (6x/day/20 s) and erosion (6x/day/20 s) with abrasion (2x/10 s) were performed for five days. Dentin volume loss was determined by 3D confocal laser microscopy. Data were analyzed with two-way ANOVA and Tukey's tests.G1 - CPP-ACP (10.77 ± 1.66) and CPP-ACP associated with Diode laser (9.98 ± 0.89) showed lower volume loss in relation Control group (12.86 ± 0.63) (p 0.05). G2 - CPP-ACP associated with Diode laser (12.41 ± 1.08) elicited lower volume loss as compared to the Control (14.42 ± 1.24) (p 0.05). As for G3 and G4, all treatments showed similar volume loss.CPP-ACP and CPP-ACP associated with Diode laser could control dental tissue loss in dentin eroded by liquid HCl. Moreover, CPP-ACP associated with Diode laser could effectively decrease dental tissue loss in dentin exposed to liquid HCl and brushing.

The use of erbium lasers to prevent caries in enamel has shown positive results. However, it is not known if Er,Cr:YSGG laser can also be used to increase acid resistance of root dentine, which is another dental tissue susceptible to the action of cariogenic bacteria. Objective: To analyze the effects of the Er,Cr:YSGG laser (λ=2.78 μm, 20 Hz) irradiation associated with 2% neutral sodium fluoride (NaF) to prevent root dentin demineralization. Material and Methods: One hundred human root dentin samples were divided into 10 groups (G) and treated as follows: G1: no treatment; G2: NaF; G3: laser (4.64 J/cm2) with water cooling (WC=5.4 mL/min); G4: laser (4.64 J/cm2) without WC; G5: laser (8.92 J/cm2) with WC; G6: laser (8.92 J/cm2) without WC; G7: laser (4.64 J/cm2) with WC and NaF; G8: laser (4.64 J/cm2) without WC and NaF; G9: laser (8.92 J/cm2) with WC and NaF; G10: laser (8.92 J/cm2) without WC and NaF. The NaF gel was applied alone or after 4 min of irradiation. After 14 days of acid challenge, the samples were sectioned and the Knoop microhardness (KHN) test was done at different depths (30, 60, 90 and 120 μm) from the outer dentin surface. Data were analyzed by one-way ANOVA and Fisher’s test (α=5%). Results: The results showed that G8 and G10 presented higher KHN than the G1 for the depths of 30 and 60 μm, indicating an increase of the acid resistance of the dentin in up to 35% (p

The aim of this study was to evaluate the effect of the Er:YAG laser and its association with fluoride (1.23% acidulate phosphate fluoride gel) on the prevention of enamel erosion. Sixty specimens were obtained from bovine enamel (4 × 4 mm), which were ground flat, polished, and randomly divided into five groups according to the preventive treatments: control-fluoride application; L--Er:YAG laser; L+F--laser + fluoride; F+L--fluoride + laser; L/F--laser/fluoride simultaneously. Half of the enamel surface was covered with nail varnish (control area), and the other half was pretreated with one of the preventive strategies to subsequently be submitted to erosive challenge. When the laser was applied, it was irradiated for 10 s with a focal length of 4 mm and 60 mJ/2 Hz. Fluoride gel was applied for 4 min. Each specimen was individually exposed to regular Coca-Cola® for 1 min, four times/day, for 5 days. Wear analysis was performed with a profilometer, and demineralization was assessed with an optical microscope. Data were analyzed using the Kruskal-Wallis test (wear)/Dunn test and ANOVA/Fisher's exact tests. The group L/F was similar to control group. The other groups showed higher wear, which did not present differences among them. In the demineralization assessment, the groups F+L and L/F showed lower demineralization in relation to the other groups. It can be concluded that none preventive method was able to inhibit dental wear. The treatments L/F and F+L showed lower enamel demineralization.

O objetivo deste trabalho in vitro foi avaliar a influência de diferentes agentes remineralizantes no tratamento de lesões erosivas em esmalte. Foram confeccionados espécimes de 4mmx4mm e 3 mm de espessura a partir da superfície vestibular de incisivos bovinos (n=10) e divididos aleatoriamente em 4 grupos. G1=aplicação do dentifrício remineralizante, G2= aplicação do agente potencializador remineralizante, G3= dentifrício remineralizante + agente potencializador remineralizante, G4=aplicação de verniz fluoretado (controle positivo), G5=nenhum tratamento (controle negativo). Os espécimes foram imersos em refrigerante durante um período de 10 dias. A rugosidade superficial foi analisada por meio de microscopia confocal de varredura a laser. Os dados foram analisados quanto à homogeneidade (Levene’s) e normalidade (Kolmogorov- Smirnov). Foram realizados testes paramétricos com análise de variância a dois critérios: fator tempo e fator tratamento, e pós-teste de Tukey para diferenciação das médias. Todos os testes estatísticos tiveram nível de significância de 5% (α=0,05). Os resultados obtidos mostraram diferenças estatisticamente significantes, demonstrando a redução da rugosidade da superfície do esmalte logo após o primeiro tratamento (G3) e para os demais grupos (G1, G2 e G4) somente após o segundo tratamento. Concluiu-se que a utilização de dentifrício composto por silicato de cálcio e fosfato de sódio influenciou na rugosidade do esmalte erodido do dente bovino.Palavras-chave: Dentifrícios. Erosão Dentária. Esmalte Dentário.Abstract The objective of this in vitro study was to evaluate the influence of different remineralizing agents in the treatment of enamel erosive lesions. Specimens of 4mmx4mm and 3mm thickness were made from the buccal surface of bovine incisors (n=10) and randomly divided into 4 groups. G1 = application of the remineralizing dentifrice, G2 = application of the remineralizing agent, G3 = remineralizing dentifrice + remineralizing agente, G4 = application of fluoride varnish (positive control), G5 = no treatment Specimens were immersed in refrigerant solution during a period of 10 days. The surface roughness was analyzed by means of confocal laser scanning microscopy. The data were analyzed for homogeneity (Levene's) and normality (Kolmogorov-Smirnov). Parametric tests with analysis of variance were performed on two criteria: time factor and treatment factor, and Tukey post-test for differentiation of means. All tests were statistically significant at 5% (α = 0.05). The results showed statistically significant difference, demonstrating the reduction of surface roughness after the first treatment (G3) and the other groups (G1, G2 and G4) only after the second treatment. It was concluded that the use of dentifrice composed of calcium silicate and sodium phosphate influenced the roughness of the eroded tooth enamel of the bovine tooth.Keywords: Dentifrices. Tooth Erosion. Tooth Enamel.

Purpose: To evaluate the effect of low and highly concentrated bleaching agents on microhardness and surface roughness of bovine enamel and root dentin. Methods: According to a randomized complete block design, 100 specimens of each substrate were assigned into five groups to be treated with bleaching agents containing carbamide peroxide (CP) at 10% (CP10); hydrogen peroxide (HP) at 7.5% (HP7.5) or 38% (HP38), or the combination of 18% of HP and 22% of CP (HP18/CP22), for 3 weeks. The control group was left untreated. Specimens were immersed in artificial saliva between bleaching treatments. Knoop surface microhardness (SMH) and average surface roughness (Ra) were measured at baseline and post-bleaching conditions. Results: For enamel, there were differences between bleaching treatments for both SMH and Ra measurements (p = 0.4009 and p = 0.7650, respectively). SMH significantly increased (p

The aim of this study was to evaluate by atomic force microscopy (AFM) the early phases and evolution of dental enamel erosion caused by hydrochloric acid exposure, simulating gastroesophageal reflux episodes. Polished bovine enamel slabs (4x4x2 mm) were selected and exposed to 0.1 mL of 0.01 M hydrochloric acid (pH=2) at 37 ?#61472;?#61616;C using five different exposure intervals (n=1): no acid exposure (control), 10 s, 20 s, 30 s and 40 s. The exposed area was analyzed by AFM in 3 regions to measure the roughness, surface area and morphological surface. The data were analyzed qualitatively. Roughness started as low as that of the control sample, Rrms=3.5 nm, and gradually increased at a rate of 0.3 nm/s, until reaching Rrms=12.5 nm at 30 s. After 40 s, the roughness presented increment of 0.40 nm only. Surface area (SA) increased until 20 s, and for longer exposures, the surface area was constant (at 30 s, SA=4.40 μm2 and at 40 s, SA=4.43 μm2). As regards surface morphology, the control sample presented smaller hydroxyapatite crystals (22 nm) and after 40 s the crystal size was approximately 60 nm. Short periods of exposure were sufficient to produce enamel demineralization in different patterns and the morphological structure was less affected by exposure to hydrochloric acid over 30 s.

The aim of this study was to assess any long-term chemical and morphological Nd:YAG laser modifications on irradiated primary enamel.Previous studies on irradiated primary human enamel employed methodologies that evaluated the short-term effects only.One hundred and eighty-six irradiated (with and/or without fluoride) primary enamel teeth from high-caries-risk children, which were exfoliated over a 1-year period, were collected, and the sample surface area was submitted for scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray energy-dispersive spectrometry (EDS). The subsurface was analyzed by Knoop microhardness and light microscopy (LM). Data were analyzed by one way ANOVA and Tukey tests (α=0.05) and Kruskall-Wallis and Tukey tests (α=0.05).FTIR analysis revealed a higher concentration of phosphate and carbonate in the irradiated (0.987±0.064) and lower concentration in the control groups (1.477±0.310). SEM analysis showed that the control samples exhibited a slightly smoother surface than the irradiated groups. The EDS analysis did not show any differences in the amount of calcium, phosphorus, or fluoride among the groups. The microhardness analysis revealed that sealant (249.86±7.15) and laser irradiation (262.44±22.69) led to higher hardness values than the negative control group (128.35±25.19). LM indicated significantly reduced caries formation in the laser (5.35±5.38%) and the laser plus acidulated phosphate fluoride (APF) groups (10.35±0.88%) compared with the negative control group (72.56±12.86%).Even with the limitations of the present study, these results suggest that Nd:YAG irradiation clinically modified the chemical composition of the enamel surface regardless of fluoride concentration, which successfully inhibited demineralization of primary tooth enamel over a 1-year period without significant morphological changes.

The aim of this study was to evaluate the influence of post-bleaching time intervals using 37% carbamide peroxide on dental substrate adhesion. Fifty bovine incisors were sectioned in two groups of 4X4 mm standard blocks to obtain 50 specimens in each group (n=50). In fifty blocks, the dentin (D) was analyzed and in the other 50 the enamel (E). Blocks were subjected to bleaching treatment and restored with Single Bond/z250 according to post-bleaching time intervals (0, 7, 14 and 21 days). Twenty-four hours after adhesive/resin cylinders on substrate confection, shear bond strength test (SBS) was performed in an universal test machine. Means in MPa and their respective standard deviations were: E – control: 31.89 (2.39); T0: 19.07 (2.00); T7: 24.97 (4.89); T14: 29.71 (4.89); T21: 40.91 (4.75) and D – control: 18.90 (3.64); T0: 2.22 (0.41); T7: 3.79 (0.75); T14: 5.95 (0.79); T21: 8.40 (0.87). Data were submitted to ANOVA and Tukey (p< 0.05) tests. The bond strength value for the enamel was statistically higher than the dentin, and both were lower than the control group that had similar results after 21 days post-bleaching. In dentin group, the control showed superior bond strength and was statistically different in relation to other times. It was concluded that bleaching had negative influence on adhesion. Therefore it is necessary to wait, at least, 21 days after bleaching to restore the enamel. AVALIACAO IN VITRO DA INFLUENCIA DE DIFERENTES INTERVALOS DE TEMPO POS-CLAREAMENTO COM PEROXIDO DE CARBAMIDA 37% NA ADESAO AO SUBSTRATO DENTAL RESUMO: O objetivo deste estudo foi avaliar a influencia do peroxido de carbamida a 37% sobre a adesao dos substratos dentarios em diferentes intervalos de tempo pos-clareamento. Cinquenta incisivos bovinos foram divididos em dois grupos de blocos padrao 4 x 4 mm para obter 50 especimes de cada grupo (n = 50). Em cinquenta blocos, a dentina (D) foi analisada e nos outros 50 o esmalte (E). Os blocos foram submetidos ao tratamento de clareamento e restaurados com Single Bond/z250 de acordo com os intervalos de tempo pos-clareamento (0, 7, 14 e 21 dias). Apos vinte e quatro horas os corpos de prova preparados com adesivo/resina foram submetidos ao teste de resistencia ao cisalhamento (SBS) em uma maquina universal de ensaio. As medias (Mpa) e seus respectivos desvios padrao foram: E - controle: 31,89 (2,39); T0: 19,07 (2,00); T7: 24,97 (4,89); T14: 29,71 (4,89); T21: 40,91 (4,75) e D - controle: 18,90 (3,64); T0: 2,22 (0,41); T7: 3,79 (0,75); T14: 5,95 (0,79); T21: 8,40 (0,87). Os dados foram submetidos a ANOVA e ao teste de Turkey (p

Dental caries is still the most prevalent chronic disease affecting human populations. Among the preventive treatments performed, it has been reported that laser irradiation combined with topical fluoride can induce an even greater increase in enamel caries resistance. The aim of this study was to evaluate the Nd:YAG laser, with or without fluoride, in occlusal caries prevention of the primary dentition. A double-blind split-mouth study design was used. Fifty-two children with high caries risk (7.6 ± 1.4 years) were selected and received the following: G1--the first molar was a negative control, and the second received a resin sealant; G2--the first molar was a negative control, and the second received laser irradiation (50 mJ, 10 Hz, 0.5 W); G3--the first molar received only acidulate phosphate fluoride (APF), and the second received APF + laser; G4--fisrt molar received only fluoride varnish, and the second received fluoride varnish + laser. Patients were followed up to 12 months to evaluate the presence of white-spot lesions and/or caries cavities by three calibrated observers. Thirty-five patients completed the study. Significant differences were found between the treatment and control groups (p 0.05). The laser-alone and resin sealant resulted in statistically lower caries formation than the negative control group (p 0.05). Nd:YAG laser irradiation in primary teeth effectively prevented occlusal caries in pits and fissures when used alone with lower energy over a 1-year period.

Most studies dealing with the caries preventive action of Nd:YAG laser have been done in permanent teeth and studies on primary teeth are still lacking. The aim of this study was to evaluate in vitro the effect of Nd:YAG laser combined or not with fluoride sources on the acid resistance of primary tooth enamel after artificial caries induction by assessing longitudinal microhardness and demineralization depth. Sixty enamel blocks obtained from the buccal/lingual surface of exfoliated human primary molars were coated with nail polish/wax, leaving only a 9 mm² area exposed on the outer enamel surface, and randomly assigned to 6 groups (n=10) according to the type of treatment: C-control (no treatment); APF: 1.23% acidulated phosphate fluoride gel; FV: 5% fluoride varnish; L: Nd:YAG laser 0.5 W/10 Hz in contact mode; APFL: fluoride gel + laser; FVL: fluoride varnish + laser. After treatment, the specimens were subjected to a des-remineralization cycle for induction of artificial caries lesions. Longitudinal microhardness data (%LMC) were analyzed by the Kruskal-Wallis test and demineralization depth data were analyzed by oneway ANOVA and Fisher’s LSD test (á=0.05). APFL and APF groups presented the lowest percentage of microhardness change (p

Devido a alterações químico-estruturais causadas pelo clareamento, os substratos dentais poderiam tornar-se mais susceptíveis a perda tecidual, principalmente se expostos a desafios erosivo/abrasivos. Desta forma, o presente estudo teve como objetivos: 1) analisar in vitro, se o esmalte e a radicular dentina clareada com diferentes agentes e concentrações, apresenta uma maior susceptibilidade ao desgaste, quando submetido a ciclos de erosão e abrasão; 2) comparar o efeito da aplicação de um agente clareador a base de peróxido de carbamida a 10% a um placebo no desgaste do esmalte e da dentina radicular, através de um modelo in situ. Os resultados do estudo in vitro mostraram que, independentemente do agente usado, o clareamento não aumentou o desgaste do esmalte frente a episódios erosivo-abrasivos. Na dentina, o desgaste foi dependente do agente clareador aplicado. Baseado no protocolo in situ adotado, o peróxido de carbamida a 10% não causou maior desgaste superficial no esmalte, mas aumentou a perda de tecido dentinário comparado ao placebo. Pode-se concluir que, em termos de desgaste superficial, o esmalte não foi afetado pelo tratamento clareador, enquanto a dentina mostrou-se mais susceptível. Assim, sugerem-se cuidados adicionais na seleção do agente clareador em situações clínicas que apresentam dentina radicular exposta. Due to the chemical and microstructural alterations caused by bleaching, the dental substrates can become more susceptible to tissue loss, mainly if exposed to erosive/abrasive challenges. Therefore, the present study had the following objectives: 1) to analyze in vitro, if enamel and root dentin that had been bleached with different agents and concentrations, were at increased risk of wear when submitted to cycles of erosion and abrasion; 2) to compare the effect of the application of a 10% carbamide peroxide bleaching agent to a placebo on wear of enamel and root dentin, through an in situ model. The results of the in vitro study showed that independent of agent used, the bleaching demonstrated no increase in the wear of enamel when exposed to the erosive-abrasive episodes. In dentin, the wear was dependent on the bleaching agent applied. Based on the in situ protocol adopted, the 10% carbamide peroxide did not cause higher wear on the enamel, but increased the wear of the root dentin compared to the placebo. It could be concluded that in terms of superficial wear, enamel was not affected by bleaching treatment, while dentin showed to be more susceptible. Thus, additional caution is suggested in the choice of the bleaching agent when root dentin is exposed.

O objetivo do presente trabalho foi avaliar diferentes tratamentos na remineralização do esmalte desmineralizado em situação de alto desafio cariogênico. Foram utilizados 55 fragmentos de esmalte bovino (4mmX4mmX2mm) planificados e polidos. Os espécimes foram cobertos com resina composta ficando exposta apenas a metade da superfície externa (2mmX4mm) e então, foram imersos em solução tampão de acetato (pH 4,7) por 43 horas para formar a lesão de desmineralização. Os espécimes foram divididos aleatoriamente em 5 grupos (n=11), de acordo com os tratamentos preventivos: 1- Controle (sem tratamento); 2- Verniz fluoretado a 5% Duraphat®; 3- Flúor-gel 1,23%; 4- MI PasteTM; e 5- MI Paste PlusTM. Os tratamentos foram realizados uma vez por semana durante 3 semanas. Nos intervalos das aplicações os espécimes foram submetidos a ciclos de pH (DES/RE) num total de 21 dias. Após a finalização da ciclagem os fragmentos foram seccionados longitudinalmente, sendo que em uma metade foi analisada a microdureza longitudinal, pelo cálculo da variação percentual da dureza e na outra metade foi avaliada a profundidade de desmineralização do esmalte através de microscopia óptica. Para a análise em FTIR, pó do esmalte foi obtido dos espécimes em três diferentes momentos: inicial sem desmineralização da superfície, após a desmineralização por 43 horas e após o tratamento. Para análise da microdureza longitudinal empregou-se a variação da dureza. Os dados foram analisados quanto a sua distribuição, porém como não foram normais realizou-se uma análise não paramétrica comparando grupo contra grupo pelo Mann Whitney test com α=5%. Para análise da profundidade de desmineralização, como os dados se apresentaram normais e homogêneos, realizou-se a análise de variância a 1 critério e teste Holm- Sidak para comparação das médias com α=5%. Para análise em FTIR fez-se apenas uma análise descritiva dos dados. Na análise dos dados pode-se observar que houve diferença estatística significante entre o grupo controle (G1) com o grupo flúor-gel (G3) (p