Indiana University-Purdue University Indianapolis (IUPUI) / Background: The importance of fluoride in the prevention of dental caries has been well documented in the literature, as it inhibits demineralization of the tooth structure and enhances remineralization. One of the major public health policies to prevent caries is to provide the population with an adequate amount of fluoride through community water fluoridation. Nowadays many people drink bottled water instead of tap water due to its easy access, convenience, and low cost. Besides fluoride, other minerals present in tap and bottled water, such as calcium and magnesium, are also important in decreasing dental caries prevalence. However, our knowledge of the role of bottled water in caries prevention and especially when combined with fluoride toothpaste usage is still poor. Objectives: The aim of this in-vitro study was to evaluate the effects of some bottled waters on fluoride toothpaste efficacy in enhancing caries lesion remineralization. Methodology: Early caries lesions were created in bovine enamel specimens and stratified into treatment groups based on Vickers surface microhardness (VHN). The present study followed a two (fluoride and fluoride-free toothpaste) by five (four bottled waters and tap water) factorial design. The treatment groups were bottled water with the following attributes: a) 309.9 ppm Ca/1.20 ppm F; b) 118.4 ppm Ca/0.16 ppm F; c) 1.00 ppm Ca/1.01 ppm F; d) 0.1 ppm Ca/0.04 ppm F, and tap water (48.7 ppm Ca/0.7 ppm F). The five water groups were paired either with 1100 ppm fluoride or fluoride-free toothpaste, yielding 10 groups. Specimens were pH-cycled for 10 days with the daily regimen comprised of twice daily toothpaste slurry, with four exposures to water in between. VHN was measured, again, and the difference calculated (ΔVHN). Data were analyzed using two-way ANOVA at a 5-percent significance level. Results: The two-way interaction between water and toothpaste was significant (p < 0.001). All groups except fluoride-free toothpaste/bottled water with 0.1 ppm Ca/0.04 ppm F (p = 0.411) had significant increases in VHN after pH cycling (p ≤ 0.023). Fluoridated toothpaste resulted in a higher rate of remineralization compared to fluoridefree toothpaste (all p < 0.001). Bottled water with 1.20 ppm F/309.9 ppm Ca exhibited the greatest extent of remineralization within fluoride toothpaste groups (p < 0.001) and higher remineralization than lower fluoride water in fluoride-free toothpaste groups (p ≤ 0.006). Within the fluoridated toothpaste group, tap water exhibited significantly less remineralization compared to all bottled waters (all p < 0.001). Conclusion: Within the limitation of this study, bottled water with higher fluoride and calcium concentrations might improve fluoridated toothpaste efficacy by enhancing remineralization of early enamel caries-like lesions.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / BACKGROUND Several studies have reported that harder enamel with higher contents of calcium (Ca), phosphorus (P) and fluorine (F) coupled with lower contents of carbonate (C), magnesium (Mg) and nitrate (N) was found to be more resistant to demineralization. Additionally, the hardness of dental enamel was found to have a strong correlation with its chemical content. However, yet to be established is the relation between the physical and chemical structure of enamel and its response to de- and remineralizing conditions. OBJECTIVES The aims of this laboratory study were: 1) To investigate the hardness and chemical content of sound enamel and their influence on demineralization; 2) To investigate these properties in demineralized enamel and their influence on remineralization; and 3) To investigate these properties in sound enamel and their influence on remineralization. MATERIALS AND METHODS Incipient subsurface caries lesions were created in 94 bovine enamel specimens using Carbopol C907 using three demineralization times. The specimens were then pH-cycled and treated using either 367 ppm F sodium fluoride or a placebo. Knoop surface microhardness (SMH), Energy dispersive X-ray spectroscopy (EDS) and Transverse microradiography (TMR) were performed on the specimens at all stages and compared between them. TMR variables included integrated mineral loss (ΔZ), Lesion depth (L) and maximum mineral density of the surface zone (SZmax). Data were analyzed using three- and four-way ANOVA and Pearson correlation coefficients were calculated. RESULTS SMH, ΔZ, L and SZmax were significantly different among stages, demineralization times and treatment. The weight% of F at the surface was significantly affected by treatment, irrespective of demineralization time. A statistically significant moderate correlation was found between SZmax and ΔZ and SZmax and L after pH cycling. SMH also correlated weakly to moderately with TMR data. CONCLUSIONS SMH and SZmax decreased while ΔZ and L increased with increased demineralization time. Both fluoride and non-fluoride specimens were able to remineralize, which emphasizes the role of saliva in mineralization. The Ca:P ratio remained stable at various stages, indicating the stoichiometric dissolution and redeposition of minerals. The greatest deposition of F was at the surface and its increase led to an increase in SMH and SZmax. SMH values showed that harder specimens at baseline and after demineralization remained hard after demineralization and pH-cycling, respectively, although this correlation was weak. Additionally, harder lesions showed less L and ΔZ and greater SZmax. RELEVANCE This in-vitro study will help better understand the caries process and the impact of physical and chemical characteristics of enamel on de- and remineralization challenges.

Este estudo in situ tem como proposta geral monitorar os processos de desmineralização e remineralização do esmalte dental humano durante e após o clareamento dental e como objetivos específicos: avaliar se o processo de desmineralização e remineralização do esmalte dental é influenciado pela utilização de agentes clareadores com diferentes composições e estimar o período necessário para que o esmalte dental clareado atinja os níveis de mineralização evidenciados anteriormente ao início do tratamento clareador. Dez voluntários participaram deste estudo utilizando dispositivos intra-orais contendo quatro fragmentos de esmalte dental humano cada que foram submetidos aos seguintes tratamentos: G1 - peróxido de hidrogênio 35% (Pola Office, SDI); G2 - peróxido de hidrogênio 7,5% (Pola Day, SDI); G3 - peróxido de hidrogênio 7,5% (Day White ACP, Discus Dental); G4 - ácido fosfórico 35% (Condicionador de ácido fosfórico 3M ESPE Scotchbond 3M ESPE). O período do estudo compreendeu 21 dias entre tratamento e monitoramento que foi realizado pelo método de fluorescência do tecido dental com o auxílio do equipamento QLF System. A análise estatística realizada pelo teste estatístico de ANOVA 2 fatores para mensurações repetidas e o teste de Tukey revelou haver diferenças estatísticas entre os tratamentos realizados e entre os tempos de mensuração. Após a realização do monitoramento do conteúdo mineral do esmalte dental durante e posteriormente ao término do tratamento clareador pode-se constatar que os agentes clareadores que apresentam composições químicas distintas ocasionaram diferentes níveis de desmineralização no esmalte dental humano, sendo que o composto ACP presente em um dos géis clareadores utilizados foi capaz de reduzir o processo de desmineralização durante o período de tratamento clareador. O período necessário para que o esmalte dental clareado atingisse os níveis de mineralização iniciais variaram em função do clareador utilizado, porém apenas o agente clareador que contém o composto ACP foi capaz de remineralizar completamente após 21 dias. / The overall proposal of this in situ study is to monitor the demineralization and remineralization process of human enamel during and after dental bleaching and its specific objectives are: to assess whether the process of demineralization and remineralization of enamel is influenced by the use of bleaching agents with different composition and estimate the time required to bleached enamel reaches the levels of mineralization observed prior to bleaching treatment. Ten volunteers participated of this study wearing intraoral devices containing four fragments of human enamel submitted to the following treatments: G1 - 35% hydrogen peroxide (Pola Office, SDI), G2 - 7.5% hydrogen peroxide (Pola Day, SDI); G3 - 7.5% hydrogen peroxide (Day White ACP, Discus Dental); G4 - 35% phosphoric acid (Scotchbond 3M ESPE, 3M ESPE). The study period comprised 21 days of treatment and monitoring. Monitoring was conducted by the quantitative light fluorescence method, with QLF System. Statistical analysis performed by the statistical two-way ANOVA for repeated measurements and Tukey tests demonstrated differences between treatments and between measurement times. Monitoring the enamel mineral content during and after the end of the bleaching treatment revealed that the bleaching agents with different chemical compositions resulted in different levels of human enamel demineralization and that, the ACP compound present in one of the bleaching agents used was able to reduce the demineralization process during the bleaching treatment. Time required for the bleaching human enamel reaches the initial levels of mineralization varied depending on the bleaching agent used, but only the bleaching agent containing ACP was able to completely remineralize enamel after 21 days.

O objetivo deste estudo foi avaliar o possível efeito da saliva in situ, associada ou não ao flúor, sobre a recuperação da estrutura dentária do esmalte desmineralizado, que recebeu profilaxia utilizando jato de bicarbonato de sódio. Para isso, foram utilizados 40 blocos de esmalte de dente bovino de 4x4 mm, os quais foram submetidos a um processo de desmineralização in vitro para a formação de lesões artificiais de cárie. Sobre a superfície destes blocos, foi aplicado o jato de bicarbonato de sódio, simulando a realização de uma profilaxia profissional. Após essa etapa, os blocos foram divididos em dois grupos (GI e GII) e montados em dispositivos intra-bucais, os quais foram utilizados por 10 voluntários, durante dois períodos experimentais de quatro horas. Os blocos do GI foram expostos diretamente à saliva in situ, enquanto os do GII, foram expostos à saliva associada ao flúor sob forma de bochecho com solução de NaF a 0,2%, durante o minuto inicial. No primeiro período experimental, metade dos voluntários fez parte do GI e a outra metade do GII, havendo uma inversão dos grupos no segundo período. As possíveis alterações ocorridas na superfície do esmalte após as etapas do experimento, foram avaliadas através de testes de microdureza Knoop (25g/5s) e da quantificação do desgaste com o auxílio de um rugosímetro. Para a comparação dos valores de microdureza e de desgaste entre os grupos, e entre as etapas de cada grupo, foi aplicada a Análise de Variância a dois Critérios (ANOVA) e o teste de Tukey, adotando-se um nível de significância de 5% (p<0,05). Os resultados do teste de microdureza mostraram uma diminuição, estatisticamente significante, nos valores de microdureza superficial do esmalte após a etapa de desmineralização (183,7KHN), quando comparada à microdureza superficial inicial (342KHN). Em seguida, após a simulação da profilaxia, houve um aumento significante da microdureza (337,3KHN), não havendo diferença estatisticamente significante entre o valor inicial. Quanto ao desgaste, a simulação da profilaxia promoveu um desgaste no esmalte desmineralizado da ordem de 0,709µm. Após a etapa de remineralização, o valor da microdureza diminuiu um pouco em relação ao valor inicial (303,7KHN), embora tenha sido próximo ao mesmo. Em relação ao valor do desgaste, foi observada uma diminuição estatisticamente significante (0,476 µm), o que representa uma diminuição de quase um terço do valor inicial. Não houve diferença estatisticamente significante entre os resultados dos grupos I e II em todas as etapas do experimento. De acordo com as condições e com a metodologia adotadas na presente pesquisa, foi possível concluir que após 4 horas de remineralização in situ houve recuperação de parte da estrutura dentária perdida devido à aplicação do jato de bicarbonato de sódio sobre o esmalte desmineralizado, apesar de a realização de um bochecho adicional com solução fluoretada não ter promovido aumento no ganho mineral em relação à ação somente da saliva. / The aim of this study was to evaluate the effect of saliva in situ, in the recovery of the superficial structure of the demineralized tooth enamel in which a sodium bicarbonate jet was applied. The effect of an additional mouthrinsing with a NaF solution was also evaluated. A total of 40 specimens of bovine enamel (4x4 mm) were processed in vitro to obtain artificial caries lesions were utilized for this study. A jet of sodium bicarbonate was applied on the surface of the specimens simulating a prophylaxis procedure. The specimens were divided in two groups(GI and GII). They were mounted in an intra-oral model used by 10 volunteers for two fourhour experiments. During the first four-hour experiment, the specimens of GI were directly exposed to saliva in situ. Those of GII were exposed to one minute mouthrinsing with 0.2% NaF. In the second four-hour experiment, the volunteers were crossed-over to the opposite experimental treatment group. The changes on the enamel surface were analyzed by the superficial microhardness test (Knoop, 25g/5s) and perfilometry, using a rugosimeter to determine the superficial dental wear. In order to compare the degree of microhardness and wear, among groups in the different experimental phases, the ANOVA and the Tukey test were used with an acceptable significance of 5% (p<0.05). The microhardness test showed a significant decrease of the initial value from 342 KHN to 183.7KHN after the demineralization phase. In the prophylaxis simulation, the microhardness value increased to 337 KHN, while a 0.709 µm wear was detected. After the remineralization procedure, there was a mild decrease on the degree of superficial microhardness to 303.7 KHN. Considering the superficial wear, it was detected a significant decrease (0.476 µm) comparing to the value found after the prophylaxis. There were no statistical differences between GI and GII in all phases of the experiment. After a four-hour period of an in situ remineralization, we concluded that it is possible to have a partial recovery of the dental structure, initially lost due to the use of sodium bicarbonate on the demineralized enamel. The performance of an additional mouthrinsing with fluoridate solution did not lead to an increase in the mineral gain.

O potencial protetor da saliva tem sido descrito como um importante fator que influencia na patogênese da erosão dentária. O objetivo desse trabalho foi avaliar o efeito remineralizador in situ da saliva sobre lesões iniciais de erosão e a sua capacidade protetora em relação à desmineralização erosiva do esmalte, através da utilização de dispositivos intrabucais palatino e mandibular em diferentes tempos de avaliação (30 min, 1h, 2h e 12h). Este estudo foi dividido em dois subprojetos, cada um com número amostral de 20 voluntários. No subprojeto I, após a avaliação da dureza de superfície inicial, os blocos de esmalte foram desmineralizados in vitro (ácido clorídrico 0,01 M por 30 segundos), selecionados e divididos aleatoriamente entre os 2 dispositivos, sendo utilizado quatro blocos por dispositivo palatino e dois blocos por dispositivo mandibular (2 dispositivos por voluntário/direito e esquerdo). Durante a etapa in situ, os voluntários foram orientados a utilizar os dispositivos durante o período máximo de 12 horas, de modo que após cada período de tempo pré-determinado, os dispositivos foram removidos da cavidade bucal para retirada dos blocos de esmalte e avaliação imediata da dureza superficial pós remineralização. No Subprojeto II, blocos de esmalte foram selecionados pela dureza de superfície inicial e distribuídos aleatoriamente entre os voluntários de acordo com o fator tempo e tipo de dispositivo intrabucal. Além destes, foi utilizado um grupo controle com blocos não submetidos à ação salivar. Na etapa in situ, para cada tempo em avaliação, os voluntários utilizaram os dispositivos com dois blocos de esmalte em cada dispositivo palatino (1 dispositivo por voluntário) e um bloco em cada mandibular (2 dispositivos por voluntário/direito e esquerdo). Imediatamente após cada fase da etapa in situ, os blocos (grupos experimentais e controle) sofreram desmineralização erosiva através da imersão em ácido clorídrico durante 30 segundos e, em seguida, a dureza superficial foi avaliada. Os dados foram analisados utilizando ANOVA 2 critérios e teste Tukey subprojeto I e Kruskal-Wallis e teste Tukey subprojeto II, considerando p<0,05. No subprojeto I, houve diferença estatisticamente significativa (p <0.0001) entre os tempos de 30 minutos e 2 horas, o qual não mostrou diferença em relação ao tempo de 12 horas. Não houve diferença na recuperação de dureza dos espécimes mantidos na maxila em relação aos espécimes mantidos na mandíbula. No subprojeto II, não se observou diferença entre os tipos de dispositivos. Porém, quando os tempos foram comparados entre si, foi observada diferença estatisticamente significativa entre os tempos de 30 minutos e 2 horas, o qual não mostrou diferença quando comparado com o período de 12 horas. Diferença estatisticamente significativa foi encontrada quando os tempos de 2 horas e 12 horas foram comparados com o grupo controle, tanto para utilização do dispositivo palatino quando mandibular. Portanto, independente do tipo de dispositivo utilizado, o tempo de 2 horas de exposição salivar apresentou potencial remineralizador, bem como promoveu algum nível de proteção em relação à desmineralização erosiva do esmalte, sendo que um aumento da exposição do esmalte à saliva (12 horas) não aumentou estes efeitos. / The protective potential of saliva has been described as an important factor that influences the pathogenesis of dental erosion. The aim of this study was to evaluate in situ the remineralizing effect of saliva on initial erosion lesions and the protective effect of saliva in relation to erosive enamel desmineralization, using palatal and mandibular appliances in different times of salivary exposure (30 min, 1h, 2h e 12h). This study consisted of two subprojects, each one with a sample size of 20 volunteers. In subproject I, after initial surface hardness evaluation, enamel blocks were demineralized in vitro (hydrochloric acid 0.01 M for 30 seconds), selected and randomly assigned between two types of appliances. Four blocks were placed on the palatal device and two blocks for the mandibular appliance (2 aplliances per volunteer / right and left). In the in situ phase, the volunteers were instructed to use the palatal and mandibular appliances for 12 hours, so that after every predetermined period of time, the enamel blocks were removed from the appliances for immediate evaluation of surface hardness (remineralization surface hardness). In subproject II, enamel blocks were selected using initial surface hardness and randomized among the volunteers according to factors time (30 min, 1h, 2h, and 12h) and types of intrabucal aplliance (palatal and mandibular). A control group with enamel blocks not subjected to salivary effect was also used. In in situ phase, the volunteers used intrabucal appliances with two enamel blocks in the palatal appliance (1 appliance per volunteer) and one block in each mandibular appliance (2 aplliances per volunteer / right and left). Imeddiatelly after use in each phase, the enamel blocks were desmineralized and the surface hardness was assessed. The data were analyzed using two-way ANOVA and Tukey test subproject I; Kruskal-Wallis and Tukey test subproject II, considering p<0.05. In subproject I, was observed a significant difference (p <0.0001) between 30 minutes and 2 hours, which showed no difference comparing to 12 hours. There was no significant difference in hardness recovery between specimens kept in the maxilla and mandibula. In subproject II, no significant difference was seen between the types of intraoral appliances. However, when times were compared, there was no difference between 30 minutes and 2 hours, which showed no difference compared to the 12 hours. Significant difference was found when the periods of 2 hours and 12 hours were compared with the control group (without exposure to saliva), for both, palatal and mandibular aplliances. Therefore, regardless of the type of appliance, 2 hours of salivary exposure showed remineralizing potential, as well as promoted some level of protection in relation to erosive enamel demineralization, and increased enamel exposure to saliva (12 hours) did not increase these effects.

O objetivo do estudo foi testar métodos de desenvolvimento de lesões artificiais de cárie não cavitadas em esmalte de dentes humanos, avaliando a capacidade da microrradiografia transversal (TMR) de diferenciar os efeitos de um dentifrício fluoretado e de um não fluoretado, a fim de selecionar modelos para estudos posteriores. A partir de dentes permanentes e decíduos, 20 blocos de esmalte de dentes permanentes e 15 de decíduos foram obtidos e selecionados por meio da microdureza de superfície. Na primeira etapa, amostras de dentes permanentes (n=5) foram submetidas ao modelo 1, que consistiu na indução de lesão pela imersão durante 96h em solução contendo 2,2mM de CaCl2, 2,2mM de KH2PO4, 0,05M de ácido acético, tendo o pH ajustado para 4,4 com 1M de KOH e, após, a ciclos de desmineralização e remineralização (des/re) por 10 dias. Os espécimes de dentes decíduos (n=5) foram imersos durante 96h em solução contendo 2,2 mM CaCl2, 2,2 mM NaH2PO4, 0,05M de ácido acético e 0,25ppmF, sendo o pH ajustado em 4,5 pela adição de 1M KOH e, após, durante 10 dias, a ciclos des/re (modelo 2). Em relação ao modelo 1, houve cavitação das lesões após os ciclos de 10 dias. Já com o modelo 2, no entanto, houve formação de lesões de subsuperfície observadas por microradiografia transversal (TMR), sem ocorrência de cavitação. Baseado nisso, o modelo 2 foi repetido em amostras de dentes permanentes (n = 5) e lesões de subsuperfície foram obtidas. Com base nesses resultados, na segunda etapa o modelo 2 foi utilizado em amostras de esmalte de dentes permanentes (n=10) e decíduos (n=10); neste momento, porém, metade das amostras foram submetidas a tratamento com dentifrício fluoretado e as demais com dentifrício sem flúor, para observar se o TMR seria capaz de detectar diferença entre tratamentos. O resultado obtido foi a formação de lesões de subsuperfície em dentes permanentes e decíduos e o método foi capaz de diferenciar ambos os tratamentos. / The aim of this study was to test methods of development of non-cavitated artificial caries lesions in human teeth enamel, analyzing the ability of transversal microrradiography to differentiate the effects of fluoride and non-fluoride dentifrices and select models to posterior experiments. From permanent and deciduous human teeth, 20 enamel blocks of permanent and 15 of deciduous teeth were obtained and selected by surface microhardness. In the first step, samples of permanent teeth (n = 5) were submitted to lesion induction by immersion during 96 hours in solution composed by 2.2mM CaCl2,2.2mM KH2PO4, 0.05M acetic acid, with pH 4.4 adjusted by 1M KOH, and, after this, to pH cycles of demineralization and remineralization (de/re) during 10 days (model 1). The specimens of deciduous teeth (n = 5) were immersed during 96 hours in solution composed by 2.2 mM CaCl2, 2.2 mM NaH2PO4, 0.05M acetic acid and 0.25ppmF, with pH 4.5 adjusted by 1M KOH and, posterior, during 10 days, to pH cycles (model 2). Concerning the model 1, occurred cavitation of the lesion after the 10 days cycles. Model 2, however, formed subsurface lesions observed by transversal microrradiography (TMR), without cavitation of the surface. Based on this result, this model was used to permanent enamel (n = 5), and was able to develop subsurface lesion. In the second step, the model 2 was applied to samples of permanent teeth enamel (n = 10) and deciduous teeth enamel (n = 10); in this moment, nevertheless, half of the samples were submitted to treatment with fluoridated dentifrice and the other with non-fluoridated dentifrice, to observe if the TMR would be able to detect difference between treatments. The result obtained was the induction of subsurface lesions in permanent and deciduous enamel, and the method was able to differentiate the treatments.

Purpose: The purpose of this study is to evaluate the effectiveness of MI Paste Plus™ in increasing remineralization and improving the esthetic appearance of white spot lesions in patients who have been treated with fixed orthodontic appliances. Material and Methods: A total of twelve subject participants aged twelve to twenty years were selected in this pilot study. The six treatment group subjects were treated with MI Paste PlusTM every three weeks in-office (4 applications) and via invisible retainer every night for a total of 12 weeks. The in-office application consisted of a 1 minute 35% phosphoric acid and a 5 minute MI Paste PlusTM contact time. At home, the subjects went about their routine oral hygiene practices, but added MI Paste PlusTM to their invisible retainer before bedtime which was worn throughout the night. Photographs and quantitative light-induced fluorescence (QLF) were used to calculate white spot lesion area and ∆F values respectively. Results: A significant difference was found in the control group for the area of the white spot lesion in antimere teeth #6 and #11. When analyzing the white spot lesion area in the treatment group, significant differences were found in tooth #6, antimere teeth #6 and #11, antimere teeth #8 and #9, as well as all teeth. ∆F values for all teeth in both the control and treatment groups were significant. Conclusion: In-office and at home treatment with MI Paste Plus™ showed a statistically significant reduction in photographic lesion area when compared to controls. Both MI Paste Plus™ and a fluoride toothpaste will provide some remineralization of white spot lesions.

Coastal sediments continuously interact with the overlying water column, collecting and decomposing the incoming rain of organic detritus into inorganic nutrients, and consuming oxygen in the process. This thesis compares the ability of two qualitatively different sediment models, a two-layer and a multi-layer model, to quantify the biogeochemical transformations that occur when detritus is decomposed in the sediment. Using sediment flux observations from a mesocosm eutrophication experiment, selected model parameters and different parameterizations for depositional fluxes of organic matter have been optimized using an evolutionary algorithm and a gradient descent algorithm respectively. Simulations with constant depositional fluxes outperformed simulations where deposition was dependent on proxies of biomass concentration in the overlying water. With these constant inputs, both sediment models produced similar nutrient fluxes across the sediment-water interface, however the multi-layer model was better able to adapt to new environments. / Opimization of the Sediment Flux Model (DiToro 2001) and the multi-layer model described in Soetaert et al. (1996).

Thesis (M.S.)--University of Michigan, 1986.