Magister Scientiae Dentium - MSc(Dent) / Introduction: Dental fluorosis is a developmental disturbance of enamel that results from ingestion of high amounts of fluoride during tooth mineralization. Drinking water remains the main source of fluoride. Other sources of fluoride include infant formula, vegetables; canned fish as well as early, improper utilization of fluoridated toothpastes in children. Knowledge of risk factors in the causation of dental fluorosis may improve strategies to prevent dental fluorosis. Objective: To determine the prevalence of dental fluorosis among children aged 12-15 years old in Athi River sub-county, Machakos County, Kenya and assess the level of knowledge on risk factors for dental fluorosis among their parents. Methodology: This was a descriptive study with an analytic component. A total of 281 children aged 12-15 years attending public primary schools within Athi River sub-county, Machakos County were included. A self-administered questionnaire was send to parents for sociodemographic characteristics and oral health practices. Children whose parents consented were examined and dental fluorosis scored according to the Thylstrup and Fejerskov index. Fourty randomly selected children were requested to bring water samples from their homes. Retail stores located in the area were visited for purchase of six different brands of bottled water. These samples were sent to a certified laboratory for fluoride analysis and reported in milligrams of fluoride per litre. Data analysis: Data was entered into SPSS version 20 and analysed for means, ANOVA of means and chi-square test of significance for categorical variables. All tests for significance were set at 95% confidence level (α≤0.05). Results: A total of 314 self-administered questionnaires were send to parents together with consent forms for their children's participation in the study. Two hundred and eighty six responded positively, giving a response rate of 91%. The overall prevalence of dental fluorosis among children aged 12-15 years was 93.4% with only 6.6% (n=19) recording a TFI score of 0. About one quarter 70(24.4%) of children had severe fluorosis with TFI scores of ≥5. The mean TFI score for all children was 3.09 (SD=2.0), with males recording a mean TF score of 3.01 (SD=2.11) and females a mean TF score of 3.16 (SD=1.88). Out of 44 water samples analysed, 29 (65.9%) had a fluoride content of less than 0.6mg/l, 5 (11.4%) had fluoride content of 0.7 - 1.5mg/l while 10 (22.7%) of samples had a fluoride content ≥1.5mg/l. The highest fluoride content recorded was 9.3mg/l, with another sample reflecting 8.9mgF/l. Three of the bottled water samples had a fluoride content of less than 0.6mg/l, while the other half of the bottled water reported 0.7 - 0.8mg/l fluoride. A majority (87.8%) of parents indicated that they had noticed children with brown staining of their permanent teeth in their community. About 80% of parents thought dental fluorosis was caused by salty water, while only 12.9% correctly identified water with high fluoride content as being responsible for the discolored teeth. Conclusion: Although about one in five water sources sampled had fluoride content of ≥1.5mg/l, the prevalence of dental fluorosis in this community was very high. Parental knowledge on the risk factors for dental fluorosis was low. Further research is necessary to identify the water distribution networks to provide sound evidence for engaging with the county authorities on provision of safe drinking water to the community.

Thesis (D.P.H.)--University of Michigan.

Thesis (D.P.H.)--University of Michigan.

Análise proteômica da matriz do esmalte nos estágios de secreção e maturação em camundongos susceptíveis ou resistentes à fluorose dentária, expostos cronicamente ao fluoreto através da água de beber. Os mecanismos pelos quais a ingestão excessiva de fluoreto (F) durante a amelogênese levam à fluorose dentária ainda não são precisamente conhecidos. Tem sido demonstrado que determinadas linhagens de camundongos são mais susceptíveis que outras à fluorose dentária, o que faz destas linhagens o modelo ideal para se estudarem os fenômenos moleculares envolvidos nesta patologia. No presente estudo, foi empregada uma abordagem proteômica para avaliar alterações na expressão de proteínas da matriz do esmalte dentário nos estágios de secreção e maturação, em duas linhagens de camundongos com diferentes susceptibilidades à fluorose (A/J, susceptível e 129P3/J, resistente). Camundongos de ambos os gêneros, representantes das linhagens 129P3/J (n=200) e A/J (n=200) foram distribuídos em dois grupos para cada linhagem, que receberam ração com baixa concentração de F e água de beber contendo 0 (controle) ou 50 mg/L F por 6 semanas. A concentração de F foi analisada no plasma e no esmalte dos incisivos. Para a análise proteômica, foi realizada a raspagem da matriz do esmalte dos incisivos, nos estágios de secreção e maturação. Para a extração das proteínas do esmalte, foram pesados 15 mg de pó da matriz do esmalte, aos quais foi adicionado 1 mL de tampão de lise contendo uréia 7 M, tiouréia 2 M, CHAPS 4 %, DTT 1 %, anfólitos carreadores 0,5 % pH 3-10 e um coquetel de inibidores de proteases. As proteínas do esmalte extraídas para cada grupo foram separadas pela técnica de eletroforese bidimensional e posteriormente submetidas a LC-ESI-MS/MS. A concentração média (±DP) de F encontrada no plasma dos camundongos foi de 0,023±0,010 e 0,019±0,007 mg/L para os animais do grupo controle, das linhagens A/J e 129P3/J, respectivamente, e de 0,151±0,043 e de 0,252±0,060 mg/L de F para os animais das linhagens A/J e 129P3/J, respectivamente, tratados com água contendo 50 mg/L de F. A ANOVA a 2 critérios revelou que houve diferença significativa entre os tratamentos (F= 658,0, p<0,0001), mas não entre as linhagens (F=3,3 p=0,075), tendo havido interação significativa entre estes critérios (F=16,50, p=0,0002). Já a concentração média (±DP) de F incorporado no esmalte dos incisivos dos camundongos foi 471,4±215,8 mg/kg e 151,7±58,8 mg/kg para os animais do grupo controle das linhagens 129P3/J e A/J, respectivamente, e 2711,2±1019,2 mg/kg, 1756,9±921,6 mg/kg para os animais das linhagens 129P3/J e A/J, respectivamente, tratados com água contendo 50 mg/L de F. A ANOVA a 2 critérios encontrou diferença significativa entre as linhagens (F=11,36, p=0,0016) e entre os tratamentos (F=103,50, p<0,0001), sem interação significativa entre ambos (F=2,82, p=0,1004). Os resultados proteômicos mostraram redução na abundância de proteínas no estágio de maturação, quando comparado com o de secreção. Foi observado que o tratamento com F aumentou consideravelmente o número de spots proteicos detectados em ambos os estágios, sendo que este aumento foi maior para os animais da linhagem A/J, indicando uma tentativa de se combater os efeitos deletérios do F e reforçando a maior susceptibilidade aos seus efeitos desta linhagem. A identificação das proteínas com expressão diferencial revelou que tanto a linhagem quanto o tratamento com F levaram à expressão diferencial de proteínas pertencentes a todas as categorias funcionais. / The mechanisms by which excessive ingestion of fluoride (F) during amelogenesis leads to fluorosis are still not precisely known. It has been shown that certain strains of mice are more susceptible to dental fluorosis than others, which turns these strains the ideal model for studying the molecular phenomena involved in this pathology. In the present study, we employed a proteomic approach to identify and evaluate changes in protein expression of secretory and maturation-stage enamel matrix in two strains of mice with different susceptibilities to dental fluorosis (A/J, susceptible and 129P3/J, resistant). Mice of both genders, from 129P3/J (n=200) and A/J (n=200) strains were divided into two groups for each strain. They received a low-F diet and drinking water containing 0 (control) or 50 mg/L F for 6 weeks. The F concentration was analyzed in plasma and enamel incisors. For proteomic analysis, the enamel matrix of secretory and maturation stages (incisors) was scrapped. For the extraction of enamel proteins, 1 ml of lysis buffer containing 7 M urea, 2 M thiourea, 4% CHAPS, 1% DTT, 0.5% ampholytes carriers pH 3-10 and a cocktail of protease inhibitors was added to 15 mg of enamel matrix powder. The enamel proteins extracted for each group were separated by two-dimensional electrophoresis and subsequently subjected to LC-ESIMS/ MS. The mean (± SD) F concentrations found in plasma were 0.023 ± 0.010 and 0.019 ±0.007 mg/L for the control group, A/J and 129P3/J strains, respectively; and 0.151 ± 0.043 and 0.252 ± 0.060 mg/L F for A/J and 129P3/J mice, respectively, treated with water containing 50 mg/L F. Two-way ANOVA revealed significant differences between treatments (F = 658.0, p <0.0001), but not between strains (F = 3.3 p = 0.075), with was significant interaction between these criteria (F = 16.50, p = 0.0002). The mean (± SD) F concentrations in the enamel of the incisors were 471.4 ± 215.8 mg/kg and 151.7 ± 58.8 mg/kg for the control group of 129P3/J and A/J strains, respectively; and 2711.2 ± 1019.2 mg/kg and 1756.9 ± 921.6 mg/kg for 129P3/J and A/J mice, respectively, treated with water containing 50 mg/L F. Two-way ANOVA detected significant differences between the strains (F=11.36, p=0.0016) and between treatments (F=103.50, p <0.0001), without significant interaction between these criteria (F=2.82, p=0.1004). The proteomic results revealed a reduction in the abundance of proteins in the maturation stage, as compared with the secretory stage. Treatment with F greatly increased the number of protein spots detected in both stages. This increase was greater for A/J mice, indicating an attempt to fight the deleterious effects of F and, thus, reinforcing the susceptibility of this strain to the effects of F. The identification of differentially expressed proteins revealed that both the strain and the treatment with F led to differential expression of proteins belonging to all functional categories.

Thesis (D.P.H.)--University of Michigan.

Thesis (D.P.H.)--University of Michigan.

Made available in DSpace on 2014-06-11T19:33:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-08-15Bitstream added on 2014-06-13T19:03:51Z : No. of bitstreams: 1 tiano_avp_dr_araca.pdf: 1276848 bytes, checksum: 96187df5ff4acd6ea158644871a8f69b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A primeira infância é uma fase importante para instituição de hábitos alimentares saudáveis que irão influenciar a qualidade da saúde bucal dos futuros adultos. Nessa fase a ingestão excessiva de flúor pode resultar no desenvolvimento de fluorose dentária e o consumo descontrolado de açúcares aumenta o risco de desenvolvimento de cárie precoce de infância. Nesta pesquisa os objetivos foram estudar a ingestão de flúor por crianças com até 36 meses de vida, matriculadas em duas creches públicas de municípios com diferentes concentrações de flúor na água de abastecimento, no período de permanência na creche, e a prevalência de cárie e sua relação com algumas variáveis. Amostras das refeições servidas para 80 crianças foram coletadas durante uma semana. As concentrações de flúor das amostras de alimentos sólidos e leite foram determinadas por eletrodo específico (Orion 9409BN) combinado a eletrodo de referência (Accumet 1362079) após difusão facilitada por hexametildisiloxano. Os alimentos líquidos adicionados com igual volume de total ionic strenght adjustment buffer (TISAB II) foram analisados por um eletrodo combinado (Orion 9609BN). Os resultados foram comparados por meio do teste Mann-Whitney. Para se determinar a prevalência de lesões de cárie dentária com cavidade (LCC) e cárie precoce de infância (CPI), e a contribuição de algumas variáveis, um total de 68 crianças foram examinadas, utilizando-se os códigos e critérios preconizados pela OMS e pela ADA (American Dental Association). Os pais das crianças foram entrevistados. O teste exato de Fisher (p<0,05) foi aplicado. Quanto à concentração de flúor, as refeições continham em média 0,204 ± 0,179 e 0,322 ± 0,242 μgF/mL (p<0,05), respectivamente nos municípios com teor reduzido... / The early childhood is an important phase to establish healthy eating habits that will influence the quality of the oral health for the future adults. At this phase, excessive fluoride intake may result in dental fluorosis development and uncontrolled consumption of sugar increases the risk of developing early childhood caries. This survey aimed to study the fluoride ingestion by children up to 36 months of life, registered in two public daycare centers from municipalities with different fluoride concentrations in the water supply, during the period of stay in daycare, and the caries prevalence and its relationship with some variables. Samples of meals served to 80 children were collected during one week. The fluoride concentrations of solid foods and milk were determined by a specific electrode (Orion 9409BN) combined with a reference electrode (Accumet 1362079) after diffusion facilitated by hexamethyldisiloxane. The beverages added with an equal volume of total ionic strength adjustment buffer (TISAB II) were analyzed by a combined electrode (Orion 9609BN). The results were compared using the Mann-Whitney test. In order to determine the prevalence of cavitated caries lesions (CCL) and early childhood caries (ECC), and the contribution of some variables, a total of 68 children were clinically examined using the same codes and criteria established by the WHO (World Health Organization) and ADA (American Dental Association). Their parents were interviewed. Fisher’s exact test (p<0.05) was applied. Mean fluoride concentrations of the meals were of 0.204 ± 0.179 and 0.322 ± 0.242 μgF/mL (p<0.05) in the municipality with low fluoride content (LFC) and in the municipality with adequate fluoride content (AFC), respectively. Daily fluoride intake in the former was 0.013 ± 0.003 mg/kg body weight/day and 0.012 ± 0.001 mg/kg body weight/day in the... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:33:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-08-14Bitstream added on 2014-06-13T20:44:31Z : No. of bitstreams: 1 santos_nb_dr_araca.pdf: 486492 bytes, checksum: ee801e0b89ebab07fe599f4eaad17a0f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A utilização do flúor como medida preventiva e terapêutica tem mudado o perfil da doença cárie dentária, no entanto o aumento da exposição a múltiplas fontes de flúor tem proporcionado uma preocupação constante sobre o aumento da prevalência e severidade da fluorose dentária. O objetivo da presente pesquisa foi analisar a ingestão total de flúor e avaliar o risco de desenvolvimento de fluorose dentária. A amostra foi composta por 55 crianças, de 18 a 36 meses de idade, que freqüentavam as creches (n=25) municipais e outras que residiam em um bairro (n=30) do município de Penedo-Al, tendo o mesmo a água de abastecimento público fluoretada. Foi aplicado, aos pais e/ou responsáveis, um questionário sobre os hábitos de higiene bucal das crianças. Para a análise da ingestão de flúor na dieta, a metodologia aplicada foi a técnica de duplicata da dieta sólida e líquida, durante dois dias consecutivos, enquanto que a ingestão de flúor pelo uso de dentifrício fluoretado foi estimada através da subtração do conteúdo de flúor contido na escova pelo conteúdo de flúor expectorado pela criança. Também foi analisada a regularidade da concentração de flúor adicionada à água da rede pública do referido município. Não existiu diferença significativa em função da ingestão total de flúor entre as crianças da creche e do bairro, respectivamente (lDP) 0,11l0,0463 e 0,09l0,0424 mgF/Kg peso/dia (Teste-t; p>0,05). A quantidade de flúor ingerida na dieta não ultrapassou a dose de risco para o desenvolvimento de fluorose preconizada de 0,05 a 0,07 mgF/Kg peso/dia. A ingestão de flúor através do dentifrício correspondeu a 64,5% do total ingerido nas creches. Fatores como: freqüência de escovação, quantidade de dentifrício colocado na escova, níveis de expectoração e a concentração de flúor solúvel do dentifrício utilizado tiveram correlação... / The use of fluoride as a preventive and as a therapeutic measure has changed the dental caries profile. However, exposure to multiple sources of fluoride and an increase in its consumption has brought about a greater and ongoing concern regarding the increase in the prevalence and incidence of dental fluorosis. The objective of this study were to assess the total fluoride ingestion by small children and the subsequent risk of developing dental fluorosis. Fifty five (55) children aged 18 to 36 months of age took past in this study. From those, 25 were enrolled in a nursery school and 30 were lifelong residents of suburbs of the city of Penedo - AL, Brazil. All children drank tap water from the public water system of Penedo, which is artificially fluoridated. All parents answered a questionnaire about the oral hygiene habits of their children. During two consecutive days all food and water ingested by each child was collected using the duplicated-plate technique. Fluoride ingestion from dentifrice was estimated by subtracting of the fluoride content in the toothbrush plus the child expectorated toothpaste-saliva slurry from the total fluoride contained in amount of toothpaste placed in the toothbrush. Fluoride in the public water system was also analyzed. There was no significant difference in total fluoride ingestion between nursery-enrolled and non-nursery-enrolled children. The meanlSD total fluoride ingestion in both groups were 0.11l0.0463 and 0.09l0.0424 mgF/Kg body weight/day, respectively (t-Test; p>0,05). Fluoride ingestion from diet did not reach the theoretical dose of 0.05-0.07 mgF/Kg body weight/day which is used to determine the risk for dental fluorosis. Fluoride ingestion from dentifrice amounted to 64.5% of total fluoride ingestion by nursery children. Factors such: toothbrushing frequency, amount of toothpaste placed in the toothbrush, quantity expectorated and ...(Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:33:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-25Bitstream added on 2014-06-13T21:05:35Z : No. of bitstreams: 1 zina_lg_dr_araca_prot.pdf: 4162883 bytes, checksum: 7d06640dedf17f5b91065d9db8fc6d66 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O consumo de fórmula infantil durante a primeira infância tem sido considerado um fator de risco em potencial para a fluorose e cárie dentária. O objetivo desta tese de doutorado foi avaliar, por meio de duas revisões sistemáticas e meta-análises, a relação entre o consumo de fórmula infantil e o risco de fluorose e cárie dentária. Para isso, foram consultadas oito bases de dados e listas de referências de artigos. A análise da relevância e abstração de dados foram realizadas em duplicata e independentemente por dois revisores. A qualidade dos estudos foi avaliada e os odds ratios, quando obtidos, foram combinados utilizando-se modelos de efeito aleatório. Na revisão sobre fluorose dentária, 41 de 969 publicações potencialmente elegíveis avaliaram o impacto da fórmula infantil no risco de fluorose dentária. Quatorze publicações não apresentaram os achados nos resultados. As restantes 27 publicações relataram os resultados em 19 estudos observacionais. Dezessete destes 19 estudos apresentaram odds ratio (OR) e entre eles o consumo de fórmula infantil esteve associado com uma maior prevalência de fluorose dentária na dentição permanente (OR global=1,8; intervalo de confiança de 95%=1,4-2,3). Observou-se significativa heterogeneidade entre os estudos (I-quadrado=66%) e evidência de viés de publicação (p=0,002). A metarregressão indicou que o odds ratio associado à fórmula infantil com a fluorose dentária aumentou em 5% para cada aumento de 0,1 ppm nos níveis de flúor da água de abastecimento (OR=1,05; intervalo de confiança de 95%=1,02-1,09). Na revisão sobre cárie dentária, 31 de 1.695 publicações elegíveis avaliaram o impacto da fórmula infantil no risco de cárie dentária. Duas publicações não apresentaram os achados nos resultados. As restantes 29 publicações relataram os resultados em 26 estudos... / Infant formula consumption during childhood has been considered a potential risk factor for enamel fluorosis and dental caries. The aim of this doctorate thesis was to evaluate, through two systematic reviews and meta-analysis, the relationship between infant formula consumption and the risk of enamel fluorosis and dental caries. Eight databases and reference list of articles were searched. Assessment of relevance and data abstraction were conducted in duplicate and independently by two reviewers. Study quality was assessed and odds ratios, when obtainable, were combined using a random-effects model. In the fluorosis systematic review, 41 out of 969 potentially eligible publications evaluated the impact of infant formula on enamel fluorosis risk. Fourteen publications did not report the findings in the results. The remaining 27 publications reported on 19 observational studies. Seventeen of these 19 studies reported odds ratio (OR) and among these infant formula consumption was associated with a higher prevalence of enamel fluorosis in the permanent dentition (summary OR=1.8; 95% confidence interval=1.4-2.3). There was significant heterogeneity among studies (I-squared=66%) and evidence of publication bias (p=0.002). A metaregression indicated that the odds ratios associating infant formula with enamel fluorosis increased by 5% for each 0.1 ppm increase in the reported levels of fluoride in the water supply (OR=1.05, 95% confidence interval=1.02-1.09). In the dental caries systematic review, 31 out of 1695 eligible publications evaluated the impact of infant formula on dental caries risk. Two publications did not report the findings in the results. The remaining 29 publications reported on 26 observational studies. General (summary OR=1.7; 95% confidence interval=1.2-2.4) and nocturnal (summary OR=2.0; 95% confidence interval=1.3- 3.0) infant... (Complete abstract, click electronic access below)

Made available in DSpace on 2014-06-11T19:27:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-28Bitstream added on 2014-06-13T20:17:06Z : No. of bitstreams: 1 camara_dm_me_araca.pdf: 818938 bytes, checksum: 54742da04cf41f01f0460d44699f8155 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Formulações de dentifrícios com concentrações reduzidas de fluoreto (F) têm sido estudadas para diminuir o risco de fluorose dentária. O objetivo do trabalho foi avaliar a eficácia de dentifrícios com concentrações reduzidas de F (250 μgF/g), suplementados com hexametafosfato (HMP) sobre a desmineralização do esmalte de dente bovino. Blocos de esmalte foram submetidos a repetidas ciclagens de pH alternadas com tratamentos (2x/dia) com dentifrícios sem F contendo HMP nas concentrações de 0, 0,25, 0,5, 1,0, 2,0 e 3,0%, dentifrícios com 250 gF/g suplementados com HMP nas mesmas concentrações, placebo (sem F e HMP), um com 500 μgF/g, outro com 1100 μgF/g e um comercial (Crest, de 1100 gF/g). Após as ciclagens determinou-se a dureza de superfície final (SHf), perda integrada de dureza de subsuperfície (ΔKHN) e o conteúdo de F no esmalte. Os resultados foram submetidos à ANOVA e teste de Bonferroni (p<0.05). O grupo 250 gF/g com 0,5% de HMP apresentou maior valor de SHf, e menor ΔKHN, seguido do grupo de 250 gF/g com 1,0% de HMP que ficou semelhante ao 1100 gF/g e Crest. HMP não interferiu na incorporação de F pelo esmalte em concentrações menores que 3%. Além disso, a adição de 0,5% de HMP a um dentifrício sem F causou um aumento de SHf e uma redução de ΔKHN em comparação ao placebo. Conclui-se que é possível reduzir a concentração de F a 250 gF/g e se obter uma ação comparável de um dentifrício comercial sobre a desmineralização do esmalte bovino através da suplementação com hexametafosfato nas concentrações de 0,5 e 1% / Formulations of dentifrices with reduced concentrations of fluoride (F) have been studied to decrease the risk of dental fluorosis. The aim of this study was to evaluate the efficacy of dentifrices with low concentration of F (250 μgF/g), supplemented with hexametaphosphate (HMP) on the demineralization of bovine tooth enamel. Blocks of enamel were submitted to repeated pH cyclings alternated with treatments (2x/day) with dentifrices without F or containing 250 gF/g supplemented with HMP at concentrations of 0, 0,25, 0,5 1,0, 2,0 e 3,0%, dentifrices supplemented with HMP the same concentrations, placebo (without F and HMP), a dentifrice with 500 μgF/g, another with 1100 μgF/g and a commercial dentifrice (Crest, 1100 gF/g). After cycling, the following analysis were conducted: final surface hardness (SHf), subsurface hardness integrated loss (ΔKHN) and the content of F on enamel. The results were submitted to variance analysis and Bonferroni test (p<0.05). The group of 250 gF/g with 0,5% HMP showed the highest SHf value and the lowest ΔKHN value, followed by the group supplemented with 1,0% HMP which was similar to 1100 gF/g and Crest groups. HMP did not impair the uptake of F by enamel at concentrations lower than3%. Furthermore the addition of 0,5% HMP to a non fluoridated dentifrice caused a rise on SHf and a decrease on ΔKHN in comparison to placebo. It was concluded that it is possible to reduce the concentration of F to 250 μgF/g and obtain an action similar to a commercial dentifrice on the demineralization of enamel by supplementation with hexametaphosphate in concentrations of 0.5 and 1%