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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.

Purpose To determine the effects of tooth brushing on the surface roughness (Sa) and morphology, maximum relative depth (Rv), gloss (GU), and microhardness (MH) of four esthetic restorative materials and enamel. Materials and methods A light-curing composite resin (Filtek Supreme Ultra [FSU], 3M ESPE), two hybrid resin/ceramic CAD/CAM materials (Lava Ultimate [LAV], 3M ESPE, and VITA Enamic [VEN], VITA Zahnfabrik), and a CAD/CAM feldspathic ceramic (VITA Blocs Mark II [VMA], VITA Zahnfabrik) were evaluated. Bovine enamel (ENA) was used as a control group. All surfaces were polished in accordance with the manufacturer's instructions. Samples were analyzed before and after brushing (30,000 cycles) regarding Sa and Rv using a 3D laser-measuring microscope. GU was evaluated every 10,000 tooth brushing cycles. MH was also measured before and after tooth brushing. The surfaces were observed using scanning electron and laser measuring microscopies to determine the wear patterns. Data were analyzed by paired t test, one-way or two-way repeated measures analysis of variance, and Tukey test (α = .05), depending on the method performed. Results The Sa increased significantly after brushing for all materials, except for VMA, which showed the opposite effect. ENA and VEN showed higher Rv than VMA. After 30,000 tooth brushing cycles, VMA showed the highest GU, while FSU showed the lowest. Also, little surface topography changes were observed for VMA. MH did not change significantly after 30,000 brushing cycles, except for LAV. Conclusion Brushing caused surface alterations in all tested materials except for feldspathic ceramic. The changes were more evident in resin-based materials.

This study evaluated how Er,Cr:YSGG laser, associated or not with 5% fluoride varnish, influences the surface roughness and volume loss of bovine root dentin submitted to erosive and/or abrasive wear. One hundred and twenty dentin specimens were divided into the groups: without preventive treatment (WPT), 5% fluoride varnish (FV); Er,Cr:YSGG laser irradiation (L), and varnish combined with laser (FV + L). The specimens (n = 10) were subdivided into: 1 = erosion (E); 2 = abrasion (A); and 3 = erosion followed by abrasion (E + A). The erosive solution used was a soft-drink (pH = 2.42 at 4ºC) applied in 5-min cycles twice a day for 10d. Abrasive wear involved brushing for 60s with an electric brush (1,600-oscillations/s) at a load of 2.0N. Surface roughness and volume loss were evaluated using a laser scanning confocal microscope. Roughness data were submitted to one-way ANOVA and Tukey post-hoc test. For volume loss, the Kruskal-Wallis and Dunn’s post-hoc tests were used (α = 5%). The lowest values of roughness were found in the control areas of all subgroups (p > 0.05). In the experimental area, the [(WPT) + (E+A)] subgroup had a significantly higher roughness (5.712 ± 0.163 μm 2 ) than the other subgroups (p < 0.05). The L and (FV + L) groups had statistically similar roughness, regardless of the type of wear. The (FV + L) group had the lowest volume loss, regardless of the type of wear performed: [(FV + L) + (E)] = 7.5%, [(FV + L) + (A) = 7.3%, and [(FV + L) + (E + A)] = 8.1%. The subgroup [(WPT) + (E + A)] had the highest volume loss (52.3%). The proposed treatments were effective in controlling dentin roughness. Laser irradiation can be an effective method to increase root dentin resistance after challenges and limit problems related to non-carious lesions.

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.

To evaluate the in vitro effects of radiotherapy (RT) on the morphological surface of the enamel and dentin and to determine the best adhesive system and most appropriate time to restore teeth in head and neck cancer patients. Sixty third molars were cut into 120 enamel fragments and 120 dentin fragments and divided into four groups (n = 30): G1 (control): nonirradiated, only restorative procedure; G2: restorative procedure immediately before RT; G3: restorative procedure immediately after RT; and G4: restorative procedure 6 months after RT. Each group was divided into two subgroups: Adper™ Single Bond 2 (SB) and Clearfill SE Bond (CL) based on the material used. After RT and restorative procedures, the specimens were subjected to confocal microscopy and shear bond strength test. Data were analyzed using a two-way ANOVA followed by Tukey’s test at a significance level of 5%. Morphological changes were observed in both substrates after a cumulative dose of 40 Gy, and after 60 Gy, the changes were more evident in both substrates. CL had the highest strength values in both substrates (p

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.

Objectives This triple-blind, 2 × 2 crossover in situ study, was undertaken to verify whether the wear resistance of enamel and root dentine would be affected by bleaching with a 10% carbamide peroxide agent and a placebo agent. Methods Thirty slabs of each substrate (2 mm × 3 mm × 2 mm) were selected for each phase, after flattening and polishing procedures and microhardness test. After a 7-day lead-in period, one specimen of each substrate was randomly bonded on the facial surface of each one of 30 subject's upper second premolars. The volunteers received instructions on how to perform toothbrushing and application of gel in the tray. Fifteen volunteers bleached their maxillary arch with a 10% carbamide peroxide bleaching agent for a 2-week period, while the remainders used a placebo agent. After a 1-week washout period, a new set of enamel and root dentine slabs were bonded to the premolars and volunteers were crossed over to the alternate agent for 14 days. The resistance of enamel and root dentine to wear following bleaching, toothbrushing and intraoral exposure was measured with a profilometer, using reference areas. Results For enamel, ANOVA did not demonstrate significant difference between wear provided by placebo and bleaching agent ( p = 0.3713), but higher wear depth was observed for bleached root dentine ( p = 0.0346). Conclusions While overnight bleaching caused no alteration in wear resistance of enamel, root dentine showed increased tissue loss.

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 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

To evaluate the enamel resistance and permeability of rat teeth to acid challenges after systemic use of sodium alendronate.Eighteen Wistar rats (36 teeth), aged 36-42 days (200-230 g), were assigned into two groups: alendronate group (n = 20 teeth), which received two weekly doses of 1 mg/kg of alendronate, via gavage; and a non-alendronate group (n = 16 teeth), which received only distilled water. After 60 days, the animals were killed, the maxillary incisors were extracted and used for the artificial induction of the caries lesion (pH cycling regimen) and erosion area (immersion cycles in cola-type soft drink) and for the enamel permeability test (dye penetration). The teeth were divided into alendronate group (n = 10) or non-alendronate group (n = 8) for each test. The quantitative response variables were the percent longitudinal change in Knoop microhardness (%LMC), the enamel carious/erosion lesion area (CELA) and enamel permeability.Groups were not significantly different (p 0.05) with regard to the %LMC and enamel permeability (25.58 μm ± 12.73 and 25.40 μm ± 4.6 for the experimental and control groups, respectively). For CELA, it was not observed significant difference (p 0.05) between the non-alendronate group (24.08 ± 1.36 and 25.22 ± 1.60, for caries and erosion, respectively) and the alendronate group (25.46 ± 1.60 and 25.0 ± 1.26) for caries and erosion, respectively).Based on the methodological conditions and the presented results of this study, sodium alendronate did not affect the longitudinal microhardness, demineralisation lesion area or permeability of the enamel after acid challenge; therefore, alendronate did not become the enamel of rats more resistant.The systemic alendronate treatment for 60 days did not change the enamel of rats regarding the susceptibility to acids.

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