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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Occurrence and Evaluation of White Spot Lesions in Orthodontic Patients: A Pilot Study

Franks, David January 2014 (has links)
Orthodontic treatment may cause an increase in the rate of enamel decalcification on tooth surfaces, producing White Spot Lesions (WSL). Orthodontic patients are at a higher risk for decalcification because orthodontic appliances retain food debris which leads to increased plaque formation. Dental plaque, an oral biofilm formed by factors including genetics, diet, hygiene, and environment, contains acid producing bacterial strains with a predominance of Mutans Streptococcus (MS). MS and others metabolize oral carbohydrates during ingestion, the byproducts of which acidify the biofilm to begin a process of enamel decalcification and formation of WSL. This study tests if patients in orthodontic treatment at Temple University can be used as subjects for further longitudinal study of WSL risk factors. Twenty patients between the ages of ten to eighteen after three months or greater of treatment were enrolled to determine if duration of treatment, hygiene, sense of coherence, obesity, diet frequencies, age and gender correlated with development of WSL. Of these, age is positively correlated with the number of untreated decayed surfaces. WSL and plaque levels may negatively correlate with increased brushing frequency and duration, while flossing frequency demonstrated a statistically significant negative correlation. This population may be suitable for further study because of its high incidence of WSL (75%), however difficulty in enrollment and patient attrition necessitates that future studies be modified. / Oral Biology
2

A method for the characterization of white spots in vacuum-arc remelted superalloys

Viosca, Alan Lee 30 July 2012 (has links)
Vacuum-Arc Remelting (VAR) is an important process for manufacturing Ti- and Ni-based superalloys. Currently, the sources and mechanisms behind microstructural anomalies produced in VAR superalloy ingots are not well understood. In order to help understand formation processes, a method of characterizing specific anomalies in VAR ingots is desired. This paper presents a method of characterizing the composition and morphology of anomalies in VAR alloy ingots using a combination of serial sectioning and X-ray fluorescence (XRF) energy dispersive spectroscopy (EDS) techniques. This process is demonstrated on a dirty white spot from an Alloy 718 sample. The white spot of interest was serial polished and 2-D XRF EDS maps were acquired at each polish depth. The EDS maps were then stacked to form a 3-D representation of the white spot. In addition, SEM and optical microscopy techniques were used to further characterize the composition and morphology of the dirty white spot. The dirty white spot is composed of both Ti-enriched and Nb-depleted regions. The 2-D EDS maps acquired with the XRF equipment provided adequate contrast for creating a 3-D representation of the Ti-rich region of the dirty white spot. However, contrast was not sufficient to create a 3-D representation of the Nb-depleted region. The XRF EDS equipment combined with SEM and optical microscopy techniques provided valuable information about the morphology and composition of the Alloy 718 dirty white spot. It is concluded that this dirty white spot was produced by fall-in from either the crown or shelf regions during the VAR process. / text
3

Risco de cárie: relação entre incidência de cárie e como variáveis manchas brancas, índice CPOS, superfícies de cárie e velocidade de fluxo de salivar / Caries risk: relationship between caries incidence and as variables white spots, DMFT index, caries surfaces and salivary flow velocity

Sousa, Maria da Luz Rosário de 13 March 1995 (has links)
O objetivo deste trabalho é analisar o Risco de Cárie através de variáveis microbiológicas: Risco Bacteriológico e da Resazurina (RB e RE); e de variáveis clínicas (superfícies de cárie, índice CPOS, manchas brancas e velocidade de fluxo salivar) designadas RF, num estudo longitudinal de 2 anos. A amostra inicial era de 97 escolares (11-13 anos) resgatando-se 55 ao final. Utilizou-se a técnica estatística Análise de Variância (ANOVA) e Comparações Múltiplas pelo Método de Tukey, com 5 por cento de significância, além do Teste de McNemar para verificar se RF era um bom triador dos grupos de risco. Os resultados mostraram que o teste RB (contagem de Streptococcus mutans na saliva) conseguiu determinar o grupo de alto risco que apresentou maior incidência de cáries. Este grupo foi melhor identificado quando a variável resposta foi incidência de cáries mais incidência de manchas brancas do que somente a incidência de cáries. Estes resultados foram semelhantes para RF. Não se conseguiu com RE, no entanto, diferenciar os grupos de risco ao nível de 5% de significância. Assim, conclui-se que tanto a variável microbiológica (RB) como as clínicas são bons parâmetros para determinar o grupo de alto risco de cárie. / The purpose of the present study was to analyse the Risk of Caries, through microbials variables - Bacteriology and Resazurin Risk (RB and RE); and clinical variables (RF) over a 2-yr period. Data are based on 97 school children (11-13 years old), recovering 55 at the final of the study. ANOVA and Tukey Test were applied at 5 per cent of significance, in addition the McNemar Test was applied to verify if RF was a good selector of the risk groups. The results showed that RB Test (number of Streptococcus mutans in saliva) identified people at higher risk of developing dental caries. This group was better identified when the resultant variable was incidence of caries plus incipient smooth surface lesions than only incidence of caries. These results were the same for RF. RE can\'t identify the groups of risk at 5 per cent of significance. It was concluded that both microbial (RB), and clinical variables were good parameters to identify people at high caries risk.
4

Risco de cárie: relação entre incidência de cárie e como variáveis manchas brancas, índice CPOS, superfícies de cárie e velocidade de fluxo de salivar / Caries risk: relationship between caries incidence and as variables white spots, DMFT index, caries surfaces and salivary flow velocity

Maria da Luz Rosário de Sousa 13 March 1995 (has links)
O objetivo deste trabalho é analisar o Risco de Cárie através de variáveis microbiológicas: Risco Bacteriológico e da Resazurina (RB e RE); e de variáveis clínicas (superfícies de cárie, índice CPOS, manchas brancas e velocidade de fluxo salivar) designadas RF, num estudo longitudinal de 2 anos. A amostra inicial era de 97 escolares (11-13 anos) resgatando-se 55 ao final. Utilizou-se a técnica estatística Análise de Variância (ANOVA) e Comparações Múltiplas pelo Método de Tukey, com 5 por cento de significância, além do Teste de McNemar para verificar se RF era um bom triador dos grupos de risco. Os resultados mostraram que o teste RB (contagem de Streptococcus mutans na saliva) conseguiu determinar o grupo de alto risco que apresentou maior incidência de cáries. Este grupo foi melhor identificado quando a variável resposta foi incidência de cáries mais incidência de manchas brancas do que somente a incidência de cáries. Estes resultados foram semelhantes para RF. Não se conseguiu com RE, no entanto, diferenciar os grupos de risco ao nível de 5% de significância. Assim, conclui-se que tanto a variável microbiológica (RB) como as clínicas são bons parâmetros para determinar o grupo de alto risco de cárie. / The purpose of the present study was to analyse the Risk of Caries, through microbials variables - Bacteriology and Resazurin Risk (RB and RE); and clinical variables (RF) over a 2-yr period. Data are based on 97 school children (11-13 years old), recovering 55 at the final of the study. ANOVA and Tukey Test were applied at 5 per cent of significance, in addition the McNemar Test was applied to verify if RF was a good selector of the risk groups. The results showed that RB Test (number of Streptococcus mutans in saliva) identified people at higher risk of developing dental caries. This group was better identified when the resultant variable was incidence of caries plus incipient smooth surface lesions than only incidence of caries. These results were the same for RF. RE can\'t identify the groups of risk at 5 per cent of significance. It was concluded that both microbial (RB), and clinical variables were good parameters to identify people at high caries risk.
5

Avaliação in vitro da morfologia e da capacidade de paralisação de lesões incipientes de cárie artificialmente induzidas em dentes decíduos após irradiação com Laser de Er:YAG / In vitro morphological assessment and inhibition of artificial incipient caries lesions after Er:YAG laser irradiation on primary teeth

Tashima, Adriana Yuri 29 May 2006 (has links)
O objetivo deste estudo in vitro foi avaliar a morfologia e a paralisação da progressão de lesões de cárie artificiais em esmalte após irradiação da superfície com laser de Er:YAG (KaVo Key II). A amostra (120 blocos de esmalte de dentes decíduos), submetida à ciclagem de pH durante 7 dias, foi divida aleatoriamente entre as fases experimentais. Na fase morfológica os espécimes receberam os seguintes tratamentos: controle (C), laser focado (LC), laser desfocado 3mm (L3), laser desfocado 6mm (L6), e foram preparados para microscopia eletrônica de varredura. Para avaliação da efetividade do laser os espécimes foram divididos entre 9 grupos experimentais: controle negativo (CN), controle positivo (CP), laser focado (LC), laser desfocado 3mm (L3), laser desfocado 6mm (L6), aplicação tópica de flúor (F), LC mais flúor (LCF), L3 mais flúor (L3F) e L6 mais flúor (L6F). Os grupos foram submetidos a novo desafio cariogênico (exceto grupo CN) seguido de preparo para microscopia de luz polarizada. Os dados obtidos foram analisados usando os testes estatísticos ANOVA e LSD. Imagens com lupa estereoscópica também foram realizadas e o resultado submetido aos testes estatísticos Qui-quadrado, Exato de Fisher e teste de concordância. A análise visual e morfológica mostrou ablação superficial da lesão de mancha branca irradiada no grupo LC, aumento de porosidade foi visualizado no grupo L3 assim como ausência de alteração morfológica no grupo L6. Os resultados da microscopia de luz polarizada mostraram que a irradiação do laser mais flúor impediu a progressão da cárie, nos grupos LCF, L3F e L6F e reduziu o corpo da lesão no grupo L6F. Pode-se concluir que a associação entre o laser de Er:YAG desfocado 6mm mais aplicação de flúor diminuiu a profundidade da lesão incipiente de cárie sem ocasionar alteração morfológica e que os demais grupos em que a associação entre laser e flúor estava presente foram efetivos na paralisação das lesões. / The aim of this in vitro study was to evaluate the morphological effects of Er:YAG laser (KaVo Key II) irradiation on artificial enamel caries lesions and its ability to arrest the progression of these lesions. The sample (120 enamel blocks from primary teeth) was previously submitted to pH-cycling and then randomly divided into the groups. In the morphological analysis, the specimens were subdivided into 4 groups: control (C), focused laser (LC), defocused laser 3mm (L3), defocused laser 6mm (L6) and then prepared for scanning electron microscopy. To evaluate the effectiveness of the laser on incipient caries lesions, the specimens were divided into 9 groups: negative control (NC), positive control (PC), focused laser (LC), defocused laser 3mm (L3), defocused laser 6mm (L6), topical fluoride application (F), LC and fluoride (LCF), L3 and fluoride (L3F) and L6 and fluoride (L6F). All groups were submitted once again to ph cycling (except NC) and prepared for polarized light microscopy. ANOVA and LSD statistical tests were used. Images were also observed under stereoscopic loupe and were submitted to Chi-square test, Fishers´ exact test and reproducibility assessment. Visual and morphological evaluations showed that superficial ablation was present on the artificial white spot caries lesions in group LC, porosity increase in group L3 and no morphological alteration in group L6. Results under polarized light microscopy showed that laser irradiation and fluoride was able to arrest the caries progression in groups LCF, L3F and L6F and reduce the lesion´s depth in L6F. In conclusion, it was detected that the association of Er:YAG defocused laser 6mm irradiation and fluoride was able to reduce the depth of the artificial incipient caries lesions without producing any morphological alteration and that the association of laser and fluoride was effective in arresting incipient caries lesions.
6

Avaliação in vitro da morfologia e da capacidade de paralisação de lesões incipientes de cárie artificialmente induzidas em dentes decíduos após irradiação com Laser de Er:YAG / In vitro morphological assessment and inhibition of artificial incipient caries lesions after Er:YAG laser irradiation on primary teeth

Adriana Yuri Tashima 29 May 2006 (has links)
O objetivo deste estudo in vitro foi avaliar a morfologia e a paralisação da progressão de lesões de cárie artificiais em esmalte após irradiação da superfície com laser de Er:YAG (KaVo Key II). A amostra (120 blocos de esmalte de dentes decíduos), submetida à ciclagem de pH durante 7 dias, foi divida aleatoriamente entre as fases experimentais. Na fase morfológica os espécimes receberam os seguintes tratamentos: controle (C), laser focado (LC), laser desfocado 3mm (L3), laser desfocado 6mm (L6), e foram preparados para microscopia eletrônica de varredura. Para avaliação da efetividade do laser os espécimes foram divididos entre 9 grupos experimentais: controle negativo (CN), controle positivo (CP), laser focado (LC), laser desfocado 3mm (L3), laser desfocado 6mm (L6), aplicação tópica de flúor (F), LC mais flúor (LCF), L3 mais flúor (L3F) e L6 mais flúor (L6F). Os grupos foram submetidos a novo desafio cariogênico (exceto grupo CN) seguido de preparo para microscopia de luz polarizada. Os dados obtidos foram analisados usando os testes estatísticos ANOVA e LSD. Imagens com lupa estereoscópica também foram realizadas e o resultado submetido aos testes estatísticos Qui-quadrado, Exato de Fisher e teste de concordância. A análise visual e morfológica mostrou ablação superficial da lesão de mancha branca irradiada no grupo LC, aumento de porosidade foi visualizado no grupo L3 assim como ausência de alteração morfológica no grupo L6. Os resultados da microscopia de luz polarizada mostraram que a irradiação do laser mais flúor impediu a progressão da cárie, nos grupos LCF, L3F e L6F e reduziu o corpo da lesão no grupo L6F. Pode-se concluir que a associação entre o laser de Er:YAG desfocado 6mm mais aplicação de flúor diminuiu a profundidade da lesão incipiente de cárie sem ocasionar alteração morfológica e que os demais grupos em que a associação entre laser e flúor estava presente foram efetivos na paralisação das lesões. / The aim of this in vitro study was to evaluate the morphological effects of Er:YAG laser (KaVo Key II) irradiation on artificial enamel caries lesions and its ability to arrest the progression of these lesions. The sample (120 enamel blocks from primary teeth) was previously submitted to pH-cycling and then randomly divided into the groups. In the morphological analysis, the specimens were subdivided into 4 groups: control (C), focused laser (LC), defocused laser 3mm (L3), defocused laser 6mm (L6) and then prepared for scanning electron microscopy. To evaluate the effectiveness of the laser on incipient caries lesions, the specimens were divided into 9 groups: negative control (NC), positive control (PC), focused laser (LC), defocused laser 3mm (L3), defocused laser 6mm (L6), topical fluoride application (F), LC and fluoride (LCF), L3 and fluoride (L3F) and L6 and fluoride (L6F). All groups were submitted once again to ph cycling (except NC) and prepared for polarized light microscopy. ANOVA and LSD statistical tests were used. Images were also observed under stereoscopic loupe and were submitted to Chi-square test, Fishers´ exact test and reproducibility assessment. Visual and morphological evaluations showed that superficial ablation was present on the artificial white spot caries lesions in group LC, porosity increase in group L3 and no morphological alteration in group L6. Results under polarized light microscopy showed that laser irradiation and fluoride was able to arrest the caries progression in groups LCF, L3F and L6F and reduce the lesion´s depth in L6F. In conclusion, it was detected that the association of Er:YAG defocused laser 6mm irradiation and fluoride was able to reduce the depth of the artificial incipient caries lesions without producing any morphological alteration and that the association of laser and fluoride was effective in arresting incipient caries lesions.
7

Efeito do pH e dureza da água em juvenis de Rhamdia quelen infectados com Ichthyophthirius multifiliis (Fouquet, 1876) / Effect of water pH and hardness in Rhamdia quelen juveniles infected with Ichthyophthirius multifiliis (Fouquet, 1876)

Garcia, Luciano de Oliveira 20 February 2008 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to determine the intensity of Ichthyophthirius multifiliis infection, as well as net ion fluxes (Na+, K+ and Cl-), in silver catfish juveniles exposed to different pHs (5, 6, 7, 8, and 9 for sixteen days), pH (5.0 and 7.0) and hardness (20, 60 and 120 mg CaCO3.L-1 for sixteen days) and the oxidative stress parameters in liver, gill and muscle of this species and submitted to different pH (5.0 and 7.0 for three days). Net Na+, K+, and Cl- fluxes were determined at different times, trophonts in the skin and gill were counted, and mortality was registered daily. After six days fish kept at pH 6.0, 7.0, 8.0 and 9.0-hardness 20 mg CaCO3.L-1 showed significantly higher cumulative mortality (100% after eight days) and number of trophonts on the skin and gill compared to pH 5.0-hardness 20 mg CaCO3.L-1. Infected silver catfish showed significantly higher Na+ and K+ effluxes in the first day, and there was a recovery (influx) after the second day compared to asymptomatic juveniles. Silver catfish juveniles infected with I.multifiliis and exposed to pHs 5.0 and 7.0 presented significantly higher TBARS levels in the liver and gills compared to asymptomatic juveniles. The activity of catalase in the liver of silver catfish juveniles infected and exposed to both pHs was significantly lower (1st and 3rd day) than in asymptomatic juveniles. The GST activity in the liver and gills of infected juveniles increased throughout all experimental period compared to asymptomatic juveniles. The muscle of infected juveniles maintained at pH 5.0 showed significantly lower TBARS levels at day three compared to asymptomatic juveniles. The CAT activity was significantly lower in the muscle of infected juveniles at pH 5.0 and 7.0 at all experimental days except day 1 at pH 7.0 compared to asymptomatic juveniles. The muscle of infected juveniles presented significantly lower GST activity in all experimental period at both pH 5.0 and 7.0 compared to asymptomatic juveniles. These results allowed us to conclude that infection by I. multifiliis is less severe in silver catfish maintained at pH 5.0-hardness 20 mg CaCO3.L-1. Increase of water hardness increases trophonts infection and impairs survival in silver catfish kept at pH 5.0, but the opposite is observed when juveniles are at pH 7.0. There was no clear evidence of a relationship between mortality and trophonts number in infected silver catfish with net ion fluxes. Infection with I. multifiliis induces liver and gill damage via lipid peroxidation products, but the same is not observed in the muscle. / O objetivo deste estudo foi determinar a intensidade da infecção pelo Ichthyophthirius multifiliis, assim como o fluxo líquido de íons (Na+, K+ e Cl-), em juvenis de jundiá expostos a diferentes pHs (5,0; 6,0; 7,0; 8,0 e 9,0 por dezesseis dias), pH (5,0 e 7,0) e dureza (20, 60 e 120 mg CaCO3/L por dezesseis dias) e os parâmetros de estresse oxidativo no fígado, brânquias e músculo nesta espécie e submetida a diferentes pHs (5,0 e 7,0 por 3 dias). O fluxo dos íons Na+, K+ e Cl- foi determinado em diferentes tempos, o número de trofontes na pele e nas brânquias foi contado e a mortalidade foi registrada diariamente. Após seis dias os peixes submetidos aos pHs 6,0; 7,0; 8,0 e 9,0-dureza de 20 mg CaCO3/L apresentaram mortalidade cumulativa (100% após oito dias) e numero de trofontes na pele e nas brânquias significativamente maior que os mantidos em pH 5,0-dureza de 20 mg CaCO3/L. Jundiás infectados apresentaram efluxo de Na+ e K+ significativamente maior no primeiro dia, havendo uma recuperação (influxo) a partir do segundo dia em relação aos juvenis assintomáticos. Juvenis de jundiá infectados com I.multifiliis e expostos aos pHs 5,0 e 7,0 apresentaram significativo aumento dos níveis de TBARS no fígado e nas brânquias em relação aos juvenis assintomáticos. A atividade da catalase no fígado dos juvenis de jundiás infectados e expostos a ambos pHs foi significativamente maior e menor (1º e 3º dia), em relação aos juvenis assintomáticos. A atividade da GST no fígado e nas brânquias aumentou durante todo o período experimental em relação aos juvenis assintomáticos. O músculo dos juvenis infectados e mantidos em pH 5,0 apresentou significativa diminuição nos níveis de TBARS no terceiro dia comparado aos juvenis assintomáticos. A atividade da catalase foi significativamente menor no músculo dos juvenis infestados e submetidos ao pH 5,0 e 7,0 em todos os dias experimentais, exceto no primeiro dia em pH 7,0 quando comparada aos juvenis assintomáticos. O músculo dos juvenis infectados apresentou atividade da GST significativamente menor em todo o período experimental em ambos pH 5,0 e 7,0 quando comparados aos juvenis assintomáticos. Estes resultados nos permitem concluir que a infecção pelo I. multifiliis é menos severa em jundiás mantidos em pH 5,0-dureza de 20 mg CaCO3/L. O aumento da dureza da água aumenta a infecção pelos trofontes e afeta a sobrevivência dos jundiás mantidos em pH 5,0, mas o oposto é observado quando os juvenis estão no pH 7,0. Não houve uma evidência clara da relação entre a mortalidade e o número de trofontes nos juvenis de jundiá infectados com o fluxo líquido de íons. A infecção por I. multifiliis induz danos no fígado e brânquias, via produtos da peroxidação lipídica, o mesmo não ficando evidenciado no músculo.
8

Efetividade do uso t?pico de fluoreto e da escova??o no controle de c?ries produzidas "in vivo"

Flor?ncio Filho, C?cero 14 August 2008 (has links)
Made available in DSpace on 2014-12-17T14:13:37Z (GMT). No. of bitstreams: 1 CiceroFF.pdf: 3167978 bytes, checksum: d9de3f0c1f071f112b7a1ab53a79b32c (MD5) Previous issue date: 2008-08-14 / The objective of this clinical study was to evaluate the effectiveness of the toothbrushing with and without fluoride and the daily fluoride rinse (NaF 0.05%) on produced white spot, in vivo. This was a clinical study, controlled, randomized and triple blind. Thirty patients were selected for orthodontics reasons from Orthodontics Specialization Course at the Brazilian Dental Association - Section of Rio Grande do Norte. In this study it was used 4 bicuspid upper and lower. They had orthodontic reason for extractions, in 35 days, at least. The sample had one hundred and twenty teeth that received orthodontic bands. The bands were fixed with polycarboxylate cement, and there was a space standardized between bands and one surface of teeth. The four bicuspid of each patients were randomized and nominated as A, B, C and D. These nominations determinated the sequence of the extractions and what was done in each tooth. All the patients had been submitted to the toothbrushing with or without fluoride for 35 days. After this period, the A tooth of each patient was extracted to serve as control. The others teeth (B, C and D) were extracted one by each week. The entire sample was analyzed through the clinical examination and by laser fluorescence (DIAGNOdent?) in three different times: before orthodontic bands, 28 days after fixed and then removed the bands and, the last one, 07 days after one of the three treatments (toothbrushing with or without fluoride, tooth paste with fluoride and mouth rinse with fluoride). At the beginning all groups (A, B, C and D) had the same conditions, no significant difference was found. The same situation was found in a clinical examination. The results of the DIAGNOdent? for the groups that used tooth paste without fluoride, with fluoride and mouth rinse with fluoride, after 28 days, there was no significant difference. Clinically, the white spot was formed in all teeth after 28 days. When it was compared the three treated groups, the group without fluoride in tooth paste had worst result than the others groups. But there was no significant association between the number of active and inactive white spots and the type of treatment that the teeth had received. The demineralization of the enamel surface, under the orthodontic bands, it happened in a few weeks. The exposition of the white spots in oral environmental resulted in an improvement, but it was not enough to return to the values from the base line, either for the toothbrushing and/or the use of fluorite mouth rinse. Mouth rinse and toothpaste with fluoride have showed to reduce the incidence of demineralization in the enamel, but none seems to be superior to another one in an in vivo study / O objetivo desse estudo cl?nico foi avaliar a efetividade da escova??o com e sem dentifr?cio fluoretado e o enxaguat?rio bucal fluoretado na forma de bochecho di?rio (NaF 0,05%) associado a escova??o com dentifr?cio fluoretado sobre as les?es brancas de esmalte produzidas in vivo. Este estudo se constituiu em um ensaio cl?nico controlado e randomizado. Para tanto, foram selecionados 32 pacientes do Curso de Especializa??o em Ortodontia da Associa??o Brasileira de Odontologia Sec??o do Estado do Rio Grande do Norte, que necessitavam como parte do tratamento de exodontias. Os cento e vinte e oito dentes receberam an?is ortod?nticos, cimentados com cimento de policarboxilato, com espa?o padronizado na superf?cie vestibular, S?tio Cariog?nico . Os quatro premolares de cada paciente foram aleatorizados individualmente, em dente A, B, C e D, com a finalidade de se determinar a seq??ncia das exodontias e os tipos de procedimentos a serem realizados para cada dente. Todos os pacientes foram submetidos ? escova??o com dentifr?cio sem fl?or por um per?odo de 35 dias. Ap?s esse per?odo, o dente A de cada paciente foi extra?do para servir como controle. Os demais dentes B, C e D foram extra?dos ap?s uma, duas e tr?s semanas, respectivamente. Os esp?cimes foram analisados atrav?s do exame cl?nico e da fluoresc?ncia a laser (DIAGNOdent?) antes da cimenta??o dos an?is ortod?nticos, 28 dias ap?s o desafio cariog?nico e 07 dias ap?s ter sido submetido a um dos tr?s tratamentos (escova??o com dentifr?cio sem fl?or, dentifr?cio com fl?or e bochecho com enxaguat?rio bucal fluoretado associado a escova??o com dentifr?cio com fl?or) institu?dos nesse estudo. Clinicamente, a les?o branca foi formada em todos os elementos dent?rios analisados ap?s 28 dias do desafio cariog?nico. Observou-se que n?o houve diferen?a estat?sticamente significativa entre as medianas para os valores do DIAGNOdent? e para os valores dos escores relacionados ao exame cl?nico entre os grupos de tratamentos ap?s 07 dias. Quando comparou-se os tr?s grupos tratados, o grupo dentifr?cio sem fl?or apresentou um n?mero de les?es brancas ativas maior que os grupos dentifr?cio com fl?or e bochecho com fl?or, nos quais ocorreu um predom?nio do n?mero de les?es brancas inativas. No entanto, n?o houve associa??o significativa entre o n?mero de les?es brancas ativas e inativas e o tipo de tratamento que os dentes receberam. A desmineraliza??o do esmalte subjacente aos an?is ortod?nticos mal adaptados ? um processo r?pido e ocorre dentro de poucas semanas. A exposi??o das les?es brancas de esmalte, ativas ao meio bucal, resulta em uma r?pida inativa??o das mesmas, mas n?o o suficiente para retornar aos valores da linha base, seja por dist?rbios mec?nicos da escova??o e/ou a utiliza??o de enxaguat?rio bucal fluoretado associado ao dentifr?cio fluoretado. Os dentifr?cios a base de fl?or e os enxaguat?rios bucais fluoretados t?m mostrado reduzir a incid?ncia de desmineraliza??o do esmalte, mas nenhum parece ser superior ao outro tomando como base o modelo de c?rie in vivo

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