Universiẗat, Diss., 2004--Münster (Westfalen).

Made available in DSpace on 2015-03-03T11:52:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-19Bitstream added on 2015-03-03T12:07:03Z : No. of bitstreams: 1 000795197.pdf: 1772879 bytes, checksum: db209535c19615b5cc1c25824a14946c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A degradação de cerâmicas odontológicas acontece na cavidade oral e em contato com soluções erosivas. Duzentos e vinte discos de cerâmica de dissilicato de lítio foram divididos em 4 grupos. As amostras do Grupo Controle (Co) foram imersas em diferentes bebidas ácidas ou em saliva artificial. Os grupos que foram expostos em fluoreto de sódio 0,05% (NaF 0,05%) e 0,2% (NaF 0,2%) ou em gel de fluoreto fosfatado acidulado a 1,23% (FFA 1,23%), foram imersos em uma dessas soluções, para em seguida serem imersos nas bebidas ácidas testadas. As amostras foram imersas nas bebidas ácidas de uso comum durante 4 horas/dia, seguido da imersão em saliva artificial, durante 21 dias. De forma contínua, as amostras dos grupos NaF 0,05%, NaF 0,2%, FFA 1,23% foram imersas nas respectivas soluções a base de flúor durante 12, 73 e 48 horas, respectivamente. A superfície das amostras foi analisada por meio da microdureza Vicker’s, rugosidade, microscopia eletrônica de varredura associada à espectroscopia de energia dispersiva (MEV/EDS) e microscopia de força atômica (AFM). Os dados de microdureza e rugosidade superficial foram submetidos à nested-ANOVA e Tukey (? = 0,05). As análises de MEV/EDS e AFM foram comparadas visualmente entre os grupos. Como resultados, pode-se observar que a imersão nas bebidas ácidas de uso comum (Grupo Co) diminuiu os valores de microdureza e aumentou os de rugosidade. A solução de fluoreto de sódio a 0,2% foi capaz de produzir reduções estatisticamente significativas nos valores de microdureza. Além disso, quando as amostras foram imersas posteriormente nas bebidas ácidas de uso comum tanto o Grupo NaF 0,05% quanto o Grupo NaF 0,2% apresentaram reduções significativas na microdureza. Não foi possível realizar leituras de microdureza na superfície das amostras do Grupo FFA 1,23% devido... / The degradation of dental ceramics occurs in oral cavity and in contact with erosive solutions. Two hundred lithium disilicate ceramic disks were divided on 4 groups. The disks of Control Group (Co) were immersed in common acid beverages or in artificial saliva. The groups that were exposed to sodium fluoride 0.05% (NaF 0.05%) and 0.2% (NaF 0.2%) or in acidulated phosphate fluoride gel 1.23% were immersed in one of these solutions followed by the immersion in common acid beverages. Specimens were immersed in the common acid beverages for 4 h day-1 followed by the immersion in artificial saliva for the remaining 20 h for 21 days. Continuously, the disks of the Groups NaF 0.05%, NaF 0.2% and APF 1.23% were immersed in each fluoride solutions for 12, 73 and 48 hours, respectively. The surface of the disks was analyzed by Vicker’s microhardness (HV), surface roughness (?m), scanning electronic microscopy associated with X-ray dispersive spectroscopy (SEM)-EDS and atomic force microscopy (AFM). Quantitative data were analyzed by ANOVA and Tukey’s test (? = 0.05). SEM and AFM images were visually compared among groups. The immersion of the disks in test common acid beverages (Co Group) affected hardness and surface roughness results. Sodium fluoride 0.2% promoted a significant decrease in hardness results. NaF 0.05% and NaF 0.2% Groups showed significant reductions in hardness results after immersion in the common acid beverages. SEM and AFM images revealed dramatic changes in the disks of APF Group which enable the hardness test. Regardless of the solution, the disks of Co Group showed a significant increase in surface roughness when comparing them with the initial results. Superior significant results of surface roughness were observed in NaF 0.2% and APF 1.23 Groups corroborated by MEV and AFM...

Resumo: Atualmente o titânio é empregado como biomaterial devido à sua biocompatibilidade e resistência à corrosão. Entretanto, íons fluoretos, freqüentemente empregados em dentifrícios bucais, podem interferir no processo de corrosão. O objetivo deste estudo foi analisar a influência de um meio fluoretado com diferentes pH nas propriedades mecânicas e na resistência à corrosão dos conjuntos implantes/componentes protéticos à base de Ti c.p., a partir dos testes de fadiga, microscopia eletrônica de varredura (MEV) e dureza. Foram simulados cinco anos de uso regular de meios de higiene oral com conteúdo de 1500 ppm de NaF, com dois diferentes pH, 7,4 e 5,3, mediante imersão das amostras nesses meios durante 184 horas e também em água destilada, grupo controle. As amostras foram testadas num durômetro Micromet 2001 (500gf/30s). Os dados dos testes de dureza foram analisados pelo teste de Wilcoxon, demonstrando que as amostras sofreram influência negativa na dureza após a ação dos íons fluoreto. Entretanto, essa influência não ocorreu nos testes de fadiga realizados em uma máquina de ensaios mecânicos MTS-810, fixada a 100.000 ciclos, 15Hz e programada com força de fadiga a 150 N. Pela análise de MEV foram constatadas evidências de corrosão na superfície das amostras após ação de íons fluoretos, entretanto pelo EDS não se verificou incorporação de íons fluoretos sobre a superfície dos conjuntos. Concluiu-se que a concentração de flúor e o pH das soluções não exerceram influência nas propriedades mecânicas. / Abstract: Titanium has been widely used as biomaterial owing to its excellent corrosion resistance, mechanical properties and biocompatibility. However, it has been reported that fluoride-containing environments can attack titanium. The aim of this study was evaluated fluoride environments influence with different pH values in the implant/abutment sets. The implants were separated into 3 groups containing 7 implants/brand: one was submerged in acid fluoride environment (NaF 1500ppm 184h pH 5.3), one in neutral fluoride environment (NaF 1500ppm 184h pH 7.4), and other group in distillated water, simulating five years of dental hygiene. Hardness and surface texture were evaluated before and after fluoride exposition by Vickers method (500gf/30s) and scanning electron microscopy (SEM), respectively. The fatigue test was performed with 100.000 load cycles, 15 Hz and 150 N. There was decrease in hardness in implants submitted to the fluoride environment. SEM and EDS evaluation showed dark stains in all implants, irrespective of fluoride pH, resulting from pitting corrosion process. All sets supported the fatigue test until 100.000 load cycles. The results demonstrated that fluoride environment there was no influence in mechanical properties of the implant/abutment sets.

AIM: The aim of this study is to compare, in a randomized clinical trial, the appearance improvement of white spot carious lesions (WSL) treated with resin infiltration (RI) – ICON®, 5% sodium fluoride (22,600 parts per million (ppm) with fluoride varnish (FV), and to assess the synergistic effect of adding Casein Phosphopeptide-Amorphous Calcium Phosphate- MI Paste® (MIP) to these treatment modalities. METHODS: Forty subjects with unrestored WSL, after debanding fixed orthodontic appliances, were recruited from the Department of Orthodontics, Henry M. Goldman School of Dental Medicine, Boston University. A randomized, split-mouth, and double-blind clinical trial design was used to allocate subjects to resin infiltration and fluoride varnish without MI Paste® (RI and FV), 20 patients, and resin infiltration and fluoride varnish with MI Paste® (RI-MIP and FV-MIP), 20 patients. Patients in the MI Paste® present treatment group given 6-weeks supply of MI Paste®. The assessment methods were: 1) patient self-assessment, 2) expert panel subjective assessment, 3) clinical caries assessment using the International Caries Detection and Assessment System (ICDAS), and 4) actual lesion size assessment. Treatment efficacy was assessed after 4-6 weeks of application. The appearance improvement was analyzed at α level of 5% and a power of 90%. RESULTS: Over 4-6 weeks, RI treatment appeared to have a higher mean difference between baseline and follow-up compared to fluoride varnish with a statistically significant difference across all assessment methods. The patient self-assessment mean difference was 1.07 (±1.49); 95% CI [0.59 - 1.55], the expert panel subjective assessment mean difference was 0.75 (±1.06); 95% CI [0.61 - 0.88], the ICDAS mean difference was 0.38 (± 0.43); 95% CI [0.24 - 0.52], and the actual size assessment mean difference was 0.07 (±0.16); 95% CI [0.01 - 0.12]. There was no statistically significant difference between the mean differences between RI and RI-MIP, nor between FV and FV-MIP across all assessment methods. CONCLUSION: The results indicate that RI is significantly better in improving the appearance of WSLs when compared to FV. There is little evidence that use of MIP adds to the improvement of the appearance of WSL in conjunction with either modality. / 2019-09-26T00:00:00Z

Text in Afrikaans / Die tydruimtelike variasie in die fluoriedinhoud vannatuurlike drinkwater en in die voorkoms van tandfluorose, die verband tussen hierdie veranderlikes asook hulle kovariasie is op 'n hoe resolusievlak in geselekteerde endemiese gebiede ondersoek. Die drie studiegebiede verskil grootliks van mekaar wat sommige fisies- en menslik-geografiese kenmerke betref, maar ondergrondse water was oral die belangrikste bron van drinkwater. Ioonspesifieke analise en laboratoriumtegnieke is gebruik om die fluoriedinhoud van die drinkwater uit 517 bronne te bepaal. Die tande van 3 068 kinders is klinies en fotografies ondersoek. Die erkende Tooth Fluorosis Index en die indeks van Dean is gebruik om die voorkoms van fluorose te beskryf. Grafiese tegnieke, beskrywende statistieke en nieparametriese analise van variansietoetse is gebruik om die voorkoms en tydruimtelike variasiepatrone van die sleutelveranderlikes in elke studiegebied, asook die verskillende ruimtelike eenhede binne die studiegebiede, te beskryf. Die verband tussen die sleutelveranderlikes asook hul intra- en interareale kovariasie is ontleed. Daar is gevind dat die fluoriedinhoud van die ondergrondse water in die Pilanesberg- en Hammanskraal-studiegebied relatief hoog tot hoog is en die in die Vrystaat-studiegebied relatief laag. Ruimtelike veranderlikheid met groot verskille oor klein afstande kenmerk die fluoriedinhoud van ondergrondse water ongeag die gesteentes waaruit dit onttrek word. Middelwaardes bied ontoereikende beskrywings van die fluoriedgehalte van die drinkwater. Die skep van nuwe drinkwaterbronne veroorsaak langtermynvariasie in die fluoriedinhoud van die beskikbare drinkwater. Fluoroseprevalensie in die studiegebiede bet van 62% tot 87% gewissel, met meer ernstige aantasting in die Pilanesberg- en Hammanskraal-gebied as in die Suid-Vrystaat. Beduidende intra-areale ruimtelike variasie is 'n wesenlike kenmerk van die voorkoms van fluorose in al drie studiegebiede. In alle gevalle het die variasiepatroon in die fluoriedinhoud van die drinkwater die in die voorkoms van fluorose slegs gedeeltelik verklaar. Sporadiese en/of periodieke kortstondige blootstelling aan hoe fluoriedkonsentrasies lei tot emstige aantasting ten spyte van die gereelde gebruik van water met 'n laefluoriedinhoud. Ligte fluorose ontwikkel geredelik in assosiasie met <0,5 mgF-/l en matige fluorose in assossiasie met 0,5-0,7 mgF-/l, die optimum konsentrasieinterval vir fluoridasie in Suid-Afrika. / The spatiotemporal variation in the fluoride content of natural drinking water and the occurrence of dental fluorosis, the relation between these variables as well as their covariation were investigated at a high resolution level in selected endemic areas. Groundwater was the most important source of drinking water in all three study areas, but they differed markedly in respect of some physical and human geographical characteristics. Ion specific analysis and laboratory techniques were used to determine the fluoride content of the water from 517 sources. The teeth of 3 068 children were examined clinically and photographically. The fluorosis was scored according to the Tooth Fluorosis Index and Dean's classification. Graphical techniques, descriptive statistics and nonparametric analysis of variance were used to describe the occurrence and variation patterns of the key variables in the different spatial units is each study area. The relation between the variables as well as their intra and interareal covariation were analysed. The fluoride content of the groundwater in the Pilanesberg and Hammanskraal areas was relatively high to high; in the southern Free State it was relatively low. Spatial variability and significant differences over small distances typify the fluoride content of the groundwater, irrespective of the aquifer. Central statistics inadequately describe the fluoride quality of the natural drinking water. The development of new water sources causes long term variation in the fluoride content of the available drinking water. Fluorosis prevalence varied form 62% to 87%, with more severe fluorosis in Pilanesberg and Hammanskraal than in the southern Free State. Significant intra-areal spatial variation is an attribute of fluorosis in all three study areas. In all cases the variation pattern in the fluoride content of the drinking water partly explained the spatial pattern in the occurrence of fluorosis. Sporadic and/or periodic brief exposure to high fluoride concentrations leads to severe fluorosis despite regul~ usage of water with a low fluoride content. Mild fluorosis readily develops in association with <0,5 mgF-1~ and medium fluorosis in association with 0,5-0,7 mgF-/l, the optimum concentration interval for fluoridation in South Africa. / Geography / D. Phil. (Geografie)

O objetivo deste estudo in vitro foi analisar o comportamento superficial do titânio comercialmente puro (grau 2 ASTM) usinado e obtido pelo processamento de metalurgia do pó sob a ação de diferentes soluções fluoretadas, através da análise do grau de corrosão em microscopia óptica (MO) e da rugosidade superficial. Além disso, o estudo se propôs a comparar essas análises com os resultados obtidos com o titânio fundido da dissertação de mestrado de Barros (2004). Todas as amostras receberam procedimento metalográfico padrão e foram divididas em grupos: Gr.1- saliva artificial com pH 7.0 (controle), Gr.2- gel de flúor fosfato acidulado a 1,23% com pH 3.5, Gr.3- gel de NaF a 2% com pH 6.5, Gr.4- solução de NaF a 0,05% com pH 4.0 e Gr.5- solução de NaF a 0,05% com pH 7.5. As amostras foram expostas a estas soluções por 1, 4, 8 e 16 min, intercaladas com imersão em saliva artificial por 24 h, e depois foram observadas em MO e MEV, a cada intervalo de tempo. As imagens em MO, 100x, foram classificadas através de escores de 0 a 4, conforme o grau de corrosão. A rugosidade foi analisada utilizando o parâmetro Ra. Os resultados da análise de MO foram tratados estatisticamente pelo teste qui-quadrado e da rugosidade pelo teste F de Snedecor e de Bonferroni (p<0,05). Nos três tipos de amostras, o Gr2 apresentou a corrosão mais severa, e os Gr.4 e 5 apresentaram os menores graus de corrosão. Entretanto, nas amostras usinadas o Gr5 apresentou uma corrosão menos acentuada em relação ao Gr4. No Gr3 houve um aumento da corrosão em função do tempo, sendo que as amostras fundidas mostraram este aumento mais rapidamente. Houve um aumento significativo na rugosidade superficial no Gr.2 nos três tipos de amostras. Nos diversos grupos, os valores de rugosidade superficial das amostras fundidas foram significantemente maiores que os das usinadas e as de metalurgia do pó. Os autores concluíram que as soluções fluoretadas de uso odontológico são danosas às superfícies do titânio fundido, usinado e metalurgia do pó, principalmente as soluções com alta concentração de fluoreto. / The purpose of this in vitro study was to analyze the superficial behavior of commercially pure titanium (grade 2, ASTM), obtained by milling or powder metallurgical process, under the action of different fluoride solutions through the analysis of corrosion grade under an optical microscope (OM) and superficial roughness. Furthermore the results obtained from such analyses were compared with the ones of cast titanium from Barross masters degree dissertation (2004). All specimens received the standard metallography procedure for titanium, and were divided into the following groups, according to the attack solution received: Gr.1- synthetic saliva with pH 7.0 (control), Gr.2- 1.23% acidulated phosphate fluoride gel with pH 3.5, Gr.3- 2% NaF gel with pH 6.5, Gr.4- 0.05% NaF solution with pH 4.0, and Gr.5- 0.05% NaF solution with pH 7.5. The specimens were exposed to these solutions for 1, 4, 8, and 16 minutes, and between each of these times they were immersed in synthetic saliva for 24 h. The surfaces of samples were observed under OM and SEM at each interval time. The images of 100x in OM were classified by means of scores which ranged from 0 to 4, according to corrosion grade. The rugosity was analyzed using Ra parameter. The results of OM analysis were statistically treated by means of Chi-square test and of rugosity through Snededor F test and Bonferroni test (p<0,05). In the three different types of samples, the Gr2 presented the most severe corrosion, and the Gr.4 and 5 showed the smallest corrosion grade. However in the milled samples Gr5 showed a less Sharp corrosion than Gr4. The corrosion grade of Gr3 increased according to time, but the cast specimens showed this increase more quickly. There was a significant increase in the superficial rugosity in the Gr.2 in the three types of samples. In the several groups the values of the superficial rugosity of the cast samples were significantly greater than the milled and powder metallurgical ones. The authors concluded that the fluoride solutions used in dentistry are harmful to the surfaces of cast, milled and powder metallurgical titanium, mainly the solutions with high fluoride concentration.

A importância da fluoretação da água de abastecimento público na prevenção da cárie dentária é reconhecida e exaustivamente estudada desde 1945. O objetivo desta pesquisa foi o de avaliar a concentração de flúor presente na água de abastecimento público de Bauru, SP, antes e depois do processo de fluoretação. Para tanto estabeleceu-se um protocolo para a coleta de amostras de água durante três dias de uma semana, a cada três meses, durante as quatro estações do ano. As amostras foram coletas na ETA e nos 27 poços que abastecem a cidade, antes e depois da fluoretação, e em 63 pontos (residências) estabelecidos a partir do mapa onde estão definidos os 19 setores de abastecimento, com a finalidade de coletar amostras em toda a extensão da rede. A análise das amostras foi realizada em duplicata, utilizando-se o eletrodo íon-sensível (Orion 9609), acoplado ao potenciômetro (Procyon, modelo 720), adicionando 1 mL de TISAB II a 1 mL da amostra. A checagem dos resultados da análise das amostras de água foi feita através de nova leitura de 10% das amostras e com uma reprodutibilidade mínima estabelecida em 90%. Não foram observadas variações na concentração do flúor naturalmente presente na água em função da sazonalidade de cada uma das estações do ano. A concentração, das 318 amostras analisadas, variou entre 0,05 e 0,15 mg F/L. Entretanto, a média das concentrações de flúor verificadas nas 297 amostras obtidas na ETA e nos poços após a fluoretação variou entre 0,26 e 6,23 mg F/L e das 697 amostras das residências, entre 0,10 e 0,91 mg F/L. A concentração de flúor presente na água de abastecimento público de Bauru, antes da fluoretação, mostrou-se constante, diferente daquela verificada após a fluoretação, que apresentou grandes oscilações na sua concentração de flúor, indicando que o sistema de abastecimento de Bauru não mantém constantes os níveis de flúor na água. / The importance of public water fluoridation for the prevention of dental caries has been scientifically recognized. The aim of this study was to evaluate the fluoride concentration of the public water supply of Bauru, SP, before and after the fluoridation, in different seasons. It was established a protocol for collecting water samples during 3 days in a week, every 3 months. Samples were collected at the Water Treatment Station and in 27 wells that supply the city, before and after fluoridation. In addition, samples were also collected in 63 points (houses), which were selected from a city map, corresponding to the 19 sections of supply, in order to represent all the distribution system. Samples were analyzed in duplicates, using an ion-sensitive electrode (Orion 9609), coupled to a potentiometer (Procyon, model SA 720), by adding 1 mL of TISAB to 1 mL of the water sample. Repeatability was checked in 10% of the samples and was higher than 90%. No differences in the natural fluoride concentration in water were observed in the four different seasons. However mean fluoride concentrations found in the 297 samples collected in the Water Treatment Station and in the wells after fluoridation varied between 0.26 and 6.23 mg F/L. For the 697 samples collected in the houses, the ranged was from 0.10 to 0.91 mg F/L. Natural fluoride concentration in the water before fluoridation was constant, differently from fluoride concentration in the public water supply after fluoridation, which spanned a wide range. This indicates that the system of supply of Bauru does not maintain constant water fluoride levels.

O aumento da prevalência de lesões erosivas tem levado a um crescente interesse por medidas preventivas e para controle de tais lesões. Este estudo avaliou in vitro e in situ o efeito da associação de fluoretos à irradiação com laser de CO2 na permeabilidade do esmalte dental erodido. Para o experimento in vitro, foram selecionados oitenta fragmentos (n=10) de esmalte bovino (3x2x2 mm). Para formação de lesão de erosão, os espécimes foram submetidos a desafios ácidos iniciais duas vezes ao dia, durante dois dias, através de um regime alternado de erosão e remineralização. Para isso, os espécimes foram imersos individualmente em 20 ml de suco de laranja (pH 3,84) por 5 min sob agitação, enxaguados com água deionizada e armazenados em saliva artificial por 4 h. Os espécimes com as lesões de erosão pré-formadas foram divididos em 4 grupos para serem submetidos aos diferentes tratamentos: amina fluoretada (AmF), tetrafluoreto de titânio (TiF4), fluoreto de sódio (NaF) e placebo. Metade dos espécimes foi irradiada no modo contínuo com laser de CO2 ( &lambda;= 10.6 µm; 2.0 W). Após a realização dos tratamentos, foram simulados novos desafios erosivos durante 2 dias, utilizando o mesmo protocolo descrito anteriormente. Terminadas as ciclagens, os espécimes foram preparados para a avaliação da permeabilidade, sendo submetidos ao método de coloração histoquímica. Uma vez obtidos os resultados do estudo in vitro, foi conduzido um experimento in situ constituído por um delineamento crossover, com duas fases de 5 dias cada. No estudo in situ, os fatores em estudo foram os tratamentos (TiF4 e placebo) e a aplicação do laser de CO2 (presente ou ausente.) Os fragmentos de esmalte bovino foram montados em dispositivo palatino para serem instalados nos participantes para a realização dos desafios erosivos, através da ingestão de 10 alíquotas de 25 ml cada, (9, 11, 13 e 15h). A avaliação da permeabilidade foi realizada conforme descrita para o estudo in vitro. Os dados foram analisados através da ANOVA e Tukey. No estudo in vitro, houve interação significativa entre fluoreto e laser (p=0,0152). Quando os géis fluoretados foram aplicados sozinhos, TiF4 promoveu menor permeabilidade do esmalte do que aquela observada após a aplicação do placebo, enquanto resultados intermediários foram encontrados para os géis de NaF e AmF. Redução na permeabilidade do esmalte foi observada quando a aplicação dos fluoretos foi associada à irradiação com laser de CO2 . No estudo in situ, houve efeito significativo da interação entre os fatores fluoreto e laser de CO2 (p = 0,0002). Em relação ao placebo, a aplicação do TiF4 reduziu significativamente a permeabilidade do esmalte, para substratos irradiados ou não. Mediante a aplicação do placebo, o laser foi capaz de reduzir significativamente a permeabilidade do esmalte, porém, quando se utilizou o TiF4, a aplicação do laser não implicou em redução da permeabilidade. Combinada à aplicação de gel fluoretado, a irradiação com laser de CO2 pode representar uma medida adjuvante no controle da permeabilidade do esmalte erodido. / The increased prevalence of erosive lesion has led to a growing interest of preventive means and to control such lesions. This study evaluated in vitro and in situ the effect of fluoride compounds combined with a CO2 laser on permeability of eroded dental enamel. To in vitro experiment, 80 bovine enamel slabs (n=10) were selected. To create erosion-like lesions, specimens were submitted to inicial erosive challenges, twice a day, during two days, through an alternating erosive and remineralizing regimen. For that, specimens were immersed in 20 ml of orange juice (pH 3.84) for 5 min under agitation, rinsed with deionized water and stored in artificial saliva for 4 h. Specimens with pre-formed lesions were divided into four groups to be treated with different fluoride gels: amine fluoride (AmF), titanium tetrafluoride (TiF4 ), sodium fluoride (NaF) and placebo. Half of the specimens were irradiated with CO2 laser ( &lambda;= 10.6 µm; 2.0 W).Then, specimens were further cycled twice through the previously described erosive-remineralizing regimen. After cycled, specimens were subjected to permeability assessment. Once the results of in vitro study were obtained, an in situ experiment, consisting of a crossover design, with 2 phases of 5 days each, was performed. To in situ study, factors involved were treatments (TiF4 and placebo) and CO2 laser irradiation (present or absent). Bovine enamel slabs (n=10) were placed in palatal device to perform erosive challenges. Volunteers ingested orange juice as 250 mL volumes 4 times per day (9,11,13,15h). Permeability assessment was performed as described to in vitro study. Data were analyzed by ANOVA and Tukey. In vitro study demonstrated significant interaction between fluoride and laser (p = 0,0152). When fluoride gels were applied alone, TiF4 provided to enamel lower permeability than that observed following placebo application, while intermediate results were found to NaF and AmF gels. Reduction of enamel permeability was observed when fluorides were combined to CO2 laser irradiation. To in situ study, there was significant interaction between fluoride and laser (p=0,0002). When compared to placebo, TiF4 application reduced significantly enamel permeability, regardless of irradiation. Through application of placebo, laser was able to reduce significantly enamel permeability; however, when TiF4 was applied, laser irradiation did not decreased permeability. Combined to fluoride gel application, CO2 laser irradiation can represent an adjunctive way in controlling eroded enamel permeability.

Este estudo foi realizado a fim de avaliar a microdureza da dentina radicular adjacente a materiais restauradores contendo fluoretos após desafios erosivos. Foi utilizado um delineamento crossover de duas fases de 4 dias consecutivos cada. Cento e doze fragmentos de dentina bovina foram obtidos, nos quais foi confeccionada uma cavidade padronizada no centro de cada um. Estas cavidades foram restauradas aleatoriamente com cimento de ionômero de vidro (Ketac-fil) ou resina composta (Filtek Z-250). Em seguida, os fragmentos restaurados foram distribuídos aleatoriamente entre os 14 voluntários, montados em aparelhos, cada um com 4 espécimes restaurados com o mesmo material. A partir do segundo dia, metade do aparelho, com dois espécimes, foi imersa em refrigerante de limão por 90 s, quatro vezes por dia, fora da boca por 3 dias. Após um intervalo de 3 dias, fragmentos restaurados com o material ainda não utilizado foram montados no aparelho e foi iniciada a segunda fase do experimento. Após os desafios erosivos, foram realizadas as medidas da microdureza da dentina adjacente às restaurações. Independente do material empregado, os espécimes erodidos apresentaram menores valores de microdureza (p<0.0001). Com relação aos materiais restauradores, foi verificado que a dentina, nas condições deste estudo, apresentou maiores valores de microdureza quando restaurada com cimento de ionômero de vidro (p<0.0001). Sendo assim, podemos concluir que o cimento de ionômero de vidro diminui a progressão da erosão da dentina radicular adjacente à restauração. / This study sought to evaluate the microhardness of root dentine adjacent to fluoride-containing restorative materials after erosive challenge. A cross-over study was performed in two phases of 4 consecutive days each. One hundred and twelve bovine root dentine slabs were obtained, and standardized box-shaped cavities were prepared at center of each specimen. The prepared cavities were randomly restored with glass-ionomer cement or composite resin. The slabs were randomly assigned among 14 volunteers, which wore intraoral palatal device containing 4 restored root dentin slabs. Starting on the second day, half of the palatal acrylic devices were immersed extraorally in a lemonade-like carbonated soft drink for 90 seconds, four times daily for 3 days. After 3-day wash-out, dentine slabs restored with the alternative material were placed into palatal appliance and the volunteers started the second phase of this study. After erosive challenges, microhardness measurements were performed. Regardless of the restorative material employed, eroded specimens demonstrated lower microhardness value (p<0.0001). At any given dentine condition examined in this study, dentine restored with glass-ionomer cement showed higher microhardness values (p<0.0001). It may be concluded that the glass-ionomer cement decreases the progression of root dentine erosion at restoration margin.

Made available in DSpace on 2014-06-11T19:27:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-12-17Bitstream added on 2014-06-13T19:15:14Z : No. of bitstreams: 1 tiano_gc_me_araca.pdf: 753020 bytes, checksum: 112d8897b7c84b5e590dd8fe0fffdb91 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O declínio mundial da cárie dentária é atribuído ao uso abrangente do flúor. Embora esse elemento seja capaz de proteger os dentes, seu uso excessivo pode levar a uma ação citotóxica causando a inibição do crescimento celular, da síntese de proteínas e até mesmo a morte celular. O primeiro objetivo deste estudo foi investigar a concentração ideal do NaF (NaF) capaz de ativar os fibroblastos gengivais de camundongos sem induzir morte celular. Observou-se que, nesses fibroblastos, a concentração de 40 μg F/mL induziu morte celular de 62,6 %. Na concentração de 20 μg F/mL a morte celular foi de apenas 22,1%. Com base nesses resultados, optou-se por utilizar a concentração de 20 μg F/mL como dose máxima para investigar os mecanismos envolvidos na ativação dos fibroblastos gengivais. Dessa forma, avaliou-se a capacidade do NaF induzir a expressão de MMP-2 e MMP-9 pelos fibroblastos gengivais de camundongos na presença ou ausência de LPS, assim como a produção da quimiocina CCL-3/MIP-1α e óxido nítrico. Avaliou-se também a participação das vias de sinalização intracelular p44/42, p38, PI3K e NF-кB envolvidas durante essa ativação, por meio da utilização dos respectivos inibidores PD98059 (50 μM), SB202190 (10 μM), LY294002 (30 μM) e dexametasona (10 μM). Observou-se que o NaF foi capaz de estimular os fibroblastos gengivais a expressarem MMP-9, mas não MMP-2, na concentração de 20 μg F/mL com pico máximo 6 horas após, retornando aos níveis normais 24 horas após. A produção da quimiocina CCL3/MIP-1α pelos fibroblastos estimulados pelo NaF também foi observada com a concentração de 20 μg F/mL com pico máximo 6 horas após estímulo. Na presença de LPS, observou-se uma potenciação da expressão de MMP-9 e produção de CCL3/MIP-1α na concentração de 20 μg F/mL, 6 horas após. / The worldwide decline of the dental caries is attributed to the widespread use of fluoride. Although this element is capable of protecting the teeth, its excessive use, can lead to a cytotoxic action, causing an inhibition of the cell growth, of the protein synthesis and even the cellular death. Based on these results, we have chosen to use a concentration of 20 μ g F/mL as maximum concentration to investigate the mechanisms involved in the activation of the gingival fibroblasts. It was observed that, on those fibroblasts, the concentration of 40 μg F/mL has resulted in a death cellular index of 62.6%. In the concentration of 20 μg F/mL the cellular death was of 22.1% only. Based on these results, the concentration of 20 μg F/mL has been chosen as maximum concentration to investigate the mechanisms involved in the activation of the gingival fibroblasts. Later, the ability of NaF to induce the expression of MMP-2 and MMP-9 in gingival fibroblasts of mice in the presence or absence of LPS has been assessed, as well as the production of chemokine CCL-3/MIP-1a and nitric oxide. It also evaluated the participation of intracellular signaling pathways p44/42, p38, PI3K e NF-kB involved in this activation, through inhibitors PD98059 (50 μM), SB202190 (10 μM), LY294002 (30 μM) e dexamethasone (10 μM). It was observed that the NaF was capable to stimulate the gingival fibroblasts to express MMP-9, at the concentration of 20 μgF/mL with maximum peak 6 hours after, returning to normal levels 24 hours after. The expression of MMP-2 was not observed. The production of chemokine CCL3/MIP-1α was also observed with the concentration of 20 μgF/mL with maximum peak 6 hours after the stimulation. In the presence of LPS, it was observed an intensification in the expression of MMP-9 and also in the production of CCL3/MIP-1α at the concentration of 20 μgF/mL, 6 hours later.