Introduction: The Atraumatic Restorative Treatment (ART) is based on the indirect pulp capping technique. In these techniques, the infected dentine is removed and a glass ionomer cement (GIC) restoration is placed on remnant demineralized dentine to allow remineralization to occur. There is some evidence from in vitro and in vivo studies that fluoride and strontium diffuse into demineralized dentine (Kitasako, Nakajima et al. 2003); Smales 2005; Ngo 2006), and may contribute to remineralization. However, it is proposed that the mineral ions diffusing from dentinal tubular fluid also contribute. Shellis (1994) and Ozok (2004) recently demonstrated that infused surrogated dentinal fluid could decrease the depth of demineralization in dentine under an acidic challenge. Objectives: This study aimed to investigate the role of Simulated Dentine Tubule Fluid (SDTF) in remineralization of the remnant demineralized dentine using an in vitro model of the ART technique. Material and method: An apparatus was developed to achieve fluid flow into the pulp chambers of molar crowns, and thus into the dentine tubules at the same hydrostatic pressure as operates in vivo. A pilot study was carried out which demonstrated that the dye can diffuse into the dentine tubules when both artificial and natural caries are present, thus validating the method. A further pilot study demonstrated that SDTF could reduce the level of calcium lost in dentine under an acidic challenge, which agreed with Shellis and Ozok’s findings. Moreover, in the presence of the SDTF, the remineralization of demineralized dentine increased with exposure to a remineralizing solution. The main experiment of this study was to investigate whether SDTF can enhance remineralization of demineralized dentine using an in vitro ART simulation method. In this experiment, Class 1 cavities of similar dimension were cut in 18 extracted, intact third molar teeth. These teeth were painted with nail varnish leaving the dentine floors exposed for generation of artificial caries (6 teeth each for 7 days, 14 days and 21 days of demineralization). Half of the demineralized cavity floor was protected with nail varnish providing a control and test side. The cavity was restored in Fuji IX which enabled a direct contact between demineralized dentine on the test half of the cavity floor and Fuji IX. A reservoir of SDTF was connected to supply SDTF under prescribed hydrostatic pressure to each pulp chamber for 21 days during which ion exchange was proceeding between GIC and demineralized dentine as demonstrated by Ngo (2005). Teeth were then detached from the system, sectioned and prepared for analysis by Electron Probe to determine profiles of Ca, P, F and Sr across the demineralized dentine under the GIC restoration. The results from this experiment, while showing an increase in calcium in the test over control side of the lesion, also showed an increase of calcium levels on both test and control side. This suggested a need to modify the model to provide evidence of the increase in calcium and other elements above the baseline profiles originally present in the demineralized dentine. The modified model was developed which sectioned the teeth into halves. Each half of the tooth was treated as an individual sample in separated experiments where one was supplied with SDTF and the other with De-ionized Distilled Water. Based on the assumption that the mineral contents in two halves of the same tooth initially were similar, any increase in mineral contents in either half of the tooth could be considered as an indication of remineralization. Other experiments were carried out to investigate the interaction between the SDTF to calcium rich materials which were applied to the demineralized dentine, and to investigate the effect of longer exposure time on remineralization. In the first experiment, Ketac Molar was used as an alternative restorative material which is calcium based restorative material. In the second experiment, CPP-ACP was applied to the demineralized dentine before placement of composite resin or glass ionomer cement restorations. In the third experiment, the exposure time of demineralized dentine under Fuji IX restoration to SDTF was increased to six weeks to look at the effect of longer periods of exposure to SDTF on overall remineralization. Results: Both the initial and enhanced models showed the effectiveness of SDTF on remineralization in vitro under GIC restorations. The results provided evidence of an initial positive equilibrium gradient between SDTF and demineralized dentine. The placement of a GIC restoration provided an added gradient in terms of calcium concentration between SDTF and the adjacent GIC restoration. If the calcium level in the restoration was higher than that in the SDTF, as occurred with Ketac Molar, the diffusion of calcium into demineralized dentine was diminished. This also occurred in the presence of CPP-ACP. In the presence of CPPACP, the calcium/phosphorus ratios in the demineralized dentine (adjacent to the restoration) was reduced and nearer to the ratio in calcium deficient apatite. However, the longer exposure time of the demineralized dentine to GIC restoration in the presence of the SDTF increased remineralization. Conclusion: Dentinal tubule fluid contributes significantly to remineralization of the partially demineralized dentine in this model of the ART technique. However, the level of remineralization is very sensitive to factors affecting the concentration gradients between critical structural elements with the SDTF and the restoration. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1325244 / Thesis (Ph.D.) -- University of Adelaide, School of Dentistry, 2008

Thesis (doctoral)--Karolinska Institutet, Stockholm, 1993. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--Karolinska Institutet, Stockholm, 1993. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Made available in DSpace on 2015-06-17T19:33:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-09-11. Added 1 bitstream(s) on 2015-06-18T12:47:51Z : No. of bitstreams: 1 000830022.pdf: 1243699 bytes, checksum: c171fde08b809b3056c4045a40af23b0 (MD5) / O objetivo deste trabalho foi avaliar in vitro o efeito de gel com baixa concentração de fluoreto suplementado com hexametafosfato na desmineralização do esmalte. Materiais e métodos. Blocos de esmalte bovinos (n = 120) foram selecionados baseados na dureza de superfície e divididos entre 6 grupos de tratamento (n=20 por grupo): a) Gel Placebo, sem F ou HMP , b) 9% HMP, c) 4500 μg F/g, d) 4500 μg F/g + 9% HMP, e) 9000 μg F/g e f) 12300 μg F/g (Gel Ácido). Blocos de esmalte bovino foram tratados uma única vez com os respectivos géis. Dez blocos de cada grupo foram analisados quanto à concentração de CaF2 e F formado . Os outros dez blocos foram submetidos à cinco ciclagens de pH (pH 4,7- 6h e pH 7,0-18h) durante 7 dias. Após as ciclagens de pH, determinou-se a dureza de superfície final (SH1) para o cálculo da porcentagem de perda da dureza de superfície (%SH) e em seguida, a concentração de CaF2 e F (retido). Subsequentemente, a %SH e perda integrada de subsuperfície (ΔKHN) foram avaliadas. Os resultados foram submetidos à ANOVA seguido do teste Student-Newman-Keuls (p < 0,05). Resultados: Os grupos 4500 9%HMP, 9000 e o gel ácido apresentaram menor %SH, os menores valores de perda integrada de subsuperfície foram encontrados nos grupos de 4500 9%HMP e Gel ácido (p > 0.05). O grupo de gel de Ácido apresentou maiores concentrações de CaF2 formado quando comparado aos demais grupos (p <0,05). Após ciclagem de pH, o grupo 4500 9% HMP e gel Ácido apresentaram concentrações semelhantes de CaF2 retidos (p > 0,05). A concentração de F formado foi semelhante entre os grupos 4500, 4500 + 9% HMP, 9000 e gel ácido (p> 0,05). Não houve alteração na concentração de F retido após a ciclagem de pH nesses grupos. Conclusão: É possível inibir a desmineralização do esmalte... / The objective of this study was to evaluate the in vitro effect of low-fluoride (F) gels supplemented with hexametaphosphate (HMP) on enamel demineralization. Materials and methods: Bovine enamel blocks (n = 120) were selected based on surface hardness (SH) and divided into six treatment groups (n = 20 per group: a) gel Placebo, b) 9%HMP, c) 4,500 μg F/g d 4,500 μg F/g + 9% HMP, e) 9,000 μg F/g and f) 12,300 μg F/g (Acid gel). Blocks were treated with respective gels only once. Ten blocks of each group were anylized about formed CaF2 concentration. The other ten blocks were subjected to five pH cycling (pH 4,7-6h and pH 7,0-18h) during seven days. After the pH cycling, it was determined the final hardness surface (SH1) to calculate the percentage of loss surface hardness (%SH) and then, the concentration the CaF2 e F (retained).The results were subjected to ANOVA followed by Student-Newman-Keuls test (p < 0.05). Results: The groups 4500 9%HMP, 9000 and Acid showed lower %SH, the lowest values ΔKHN were found for the 4500 9%HMP and Acid gel (p > 0.05). The gel acid group showed higher concentrations the CaF2 formed when compared to the other groups (p <0,05). After all cycles of pH, the group 4500 9% HMP and acid gel showed similar concentrations the CaF2 retained (p > 0,05). The concentration the F formed was similar the groups 4,500, 4,500 + 9% HMP, 9,000 and acid gel (p>0,05). There was no chance in the concentration the F retained after all cycles of pH these groups. Conclusion: It is possible to inhibit enamel demineralization with low-F gels supplementing these gels with 9% HMP. Clinical relevance: The low-F gel containing HMP can be regarded as a safer alternative for clinical use from...

Made available in DSpace on 2015-09-17T15:24:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-09-29. Added 1 bitstream(s) on 2015-09-17T15:47:46Z : No. of bitstreams: 1 000836376.pdf: 582706 bytes, checksum: 7513ecce665994b98dbd6c2d90673ba0 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Com o objetivo de identificar a prevalência, severidade, relação com a cárie dentária e possíveis fatores etiológicos envolvidos na Hipomineralização Molar - Incisivo, foram examinados 1124 escolares da área rural e urbana de Manaus/Am. Para diagnóstico da HMI utilizou-se critérios da EAPD e para cárie dentária, CPOD e ceod. Um questionário semi-estruturado foi respondido pelas mães para investigação da saúde gestacional e da criança nos primeiros anos de vida, fatores socioeconômicos e demográficos. Os dados foram tabulados e analisados por meio de estatística descritiva, associação entre as variáveis pelo teste Qui-quadrado, Mann-Whitney, método backward e Odds ratio. A prevalência da HMI em Manaus foi de 8,9%, não sendo observada diferença relacionada à zona de moradia, gênero ou idade nas crianças diagnosticadas (p>0,05). A alteração dentária estudada foi observada com maior frequência no arco inferior sendo os primeiros molares os mais afetados. A severidade leve foi o diagnóstico mais frequente. A experiência de cárie foi maior na zona rural e na Zona urbana observou-se estreita relação entre esta e HMI. Nenhuma associação foi observada entre HMI, fatores socioeconômicos e história médica da mãe, no entanto, observou-se associação significativa com prematuridade (p= 0,01), icterícia/falta de oxigênio pós-parto (p=0,04). A HMI apresenta-se como grave problema para as crianças afetadas e profissional de saúde, devido à complexidade dos sinais e sintomas apresentados, sendo necessária realização de estudos prospectivos para elucidação da etiologia. / With the purpose of identifying the relationship between dental caries and possible etiologic factors, prevalence, severity of molar-incisor hypomineralization (MIH), 1,124 schoolchildren from rural and urban area in Manaus, Amazonas, were examined. We used the criteria established EAPD and to diagnose MIH and the DMFT and deft indices to diagnose dental caries. A semi-structured questionnaire was completed by the mothers to investigate gestational health and the child's health during the first years of life, as well as the socioeconomic and demographic factors. Data were tabulated and analyzed using descriptive statistics and the chi-square test, Mann-Whitney test, backward method, and odds ratio were used to correlate the variables. The prevalence of MIH in Manaus was 8.9%, not being related to housing area, gender or age of the children diagnosed (p>0,05). Dental alteration was more frequently observed in the lower arch and the first molars were the most affected. The most frequent diagnosis was mild severity. Dental caries experience was higher in rural areas, but in Urban area there was a close relationship between this and the HMI. No association was observed among MIH, socioeconomic factors, and the medical history of the mother, however, a significant association was found among prematurity (p = 0.01), jaundice or lack of oxygen after birth (p = 0.04). MIH is a severe problem for both the children affected and the health professionals due to the complex signs and symptoms, requiring prospective studies to elucidate the etiology.

Orientador: Alberto Carlos Botazzo Delbem / Banca: Marcelle Danelon / Banca: Fernanda Lourenção Brighenti / Resumo: O objetivo deste trabalho foi avaliar in vitro o efeito de gel com baixa concentração de fluoreto suplementado com hexametafosfato na desmineralização do esmalte. Materiais e métodos. Blocos de esmalte bovinos (n = 120) foram selecionados baseados na dureza de superfície e divididos entre 6 grupos de tratamento (n=20 por grupo): a) Gel Placebo, sem F ou HMP , b) 9% HMP, c) 4500 μg F/g, d) 4500 μg F/g + 9% HMP, e) 9000 μg F/g e f) 12300 μg F/g (Gel Ácido). Blocos de esmalte bovino foram tratados uma única vez com os respectivos géis. Dez blocos de cada grupo foram analisados quanto à concentração de CaF2 e F formado . Os outros dez blocos foram submetidos à cinco ciclagens de pH (pH 4,7- 6h e pH 7,0-18h) durante 7 dias. Após as ciclagens de pH, determinou-se a dureza de superfície final (SH1) para o cálculo da porcentagem de perda da dureza de superfície (%SH) e em seguida, a concentração de CaF2 e F (retido). Subsequentemente, a %SH e perda integrada de subsuperfície (ΔKHN) foram avaliadas. Os resultados foram submetidos à ANOVA seguido do teste Student-Newman-Keuls (p < 0,05). Resultados: Os grupos 4500 9%HMP, 9000 e o gel ácido apresentaram menor %SH, os menores valores de perda integrada de subsuperfície foram encontrados nos grupos de 4500 9%HMP e Gel ácido (p > 0.05). O grupo de gel de Ácido apresentou maiores concentrações de CaF2 formado quando comparado aos demais grupos (p <0,05). Após ciclagem de pH, o grupo 4500 9% HMP e gel Ácido apresentaram concentrações semelhantes de CaF2 retidos (p > 0,05). A concentração de F formado foi semelhante entre os grupos 4500, 4500 + 9% HMP, 9000 e gel ácido (p> 0,05). Não houve alteração na concentração de F retido após a ciclagem de pH nesses grupos. Conclusão: É possível inibir a desmineralização do esmalte... / Abstract: The objective of this study was to evaluate the in vitro effect of low-fluoride (F) gels supplemented with hexametaphosphate (HMP) on enamel demineralization. Materials and methods: Bovine enamel blocks (n = 120) were selected based on surface hardness (SH) and divided into six treatment groups (n = 20 per group: a) gel Placebo, b) 9%HMP, c) 4,500 μg F/g d 4,500 μg F/g + 9% HMP, e) 9,000 μg F/g and f) 12,300 μg F/g (Acid gel). Blocks were treated with respective gels only once. Ten blocks of each group were anylized about formed CaF2 concentration. The other ten blocks were subjected to five pH cycling (pH 4,7-6h and pH 7,0-18h) during seven days. After the pH cycling, it was determined the final hardness surface (SH1) to calculate the percentage of loss surface hardness (%SH) and then, the concentration the CaF2 e F (retained).The results were subjected to ANOVA followed by Student-Newman-Keuls test (p < 0.05). Results: The groups 4500 9%HMP, 9000 and Acid showed lower %SH, the lowest values ΔKHN were found for the 4500 9%HMP and Acid gel (p > 0.05). The gel acid group showed higher concentrations the CaF2 formed when compared to the other groups (p <0,05). After all cycles of pH, the group 4500 9% HMP and acid gel showed similar concentrations the CaF2 retained (p > 0,05). The concentration the F formed was similar the groups 4,500, 4,500 + 9% HMP, 9,000 and acid gel (p>0,05). There was no chance in the concentration the F retained after all cycles of pH these groups. Conclusion: It is possible to inhibit enamel demineralization with low-F gels supplementing these gels with 9% HMP. Clinical relevance: The low-F gel containing HMP can be regarded as a safer alternative for clinical use from... / Mestre

Orientador: Lourdes dos Santos-Pinto / Banca: Angela Cristina Cilense Zuanon / Banca: Rita de Cássia Loiola Cordeiro / Banca: Leticia Vartgas Freire Martins Lemos / Banca: Simone Assayag Hanan / Resumo: Com o objetivo de identificar a prevalência, severidade, relação com a cárie dentária e possíveis fatores etiológicos envolvidos na Hipomineralização Molar - Incisivo, foram examinados 1124 escolares da área rural e urbana de Manaus/Am. Para diagnóstico da HMI utilizou-se critérios da EAPD e para cárie dentária, CPOD e ceod. Um questionário semi-estruturado foi respondido pelas mães para investigação da saúde gestacional e da criança nos primeiros anos de vida, fatores socioeconômicos e demográficos. Os dados foram tabulados e analisados por meio de estatística descritiva, associação entre as variáveis pelo teste Qui-quadrado, Mann-Whitney, método backward e Odds ratio. A prevalência da HMI em Manaus foi de 8,9%, não sendo observada diferença relacionada à zona de moradia, gênero ou idade nas crianças diagnosticadas (p>0,05). A alteração dentária estudada foi observada com maior frequência no arco inferior sendo os primeiros molares os mais afetados. A severidade leve foi o diagnóstico mais frequente. A experiência de cárie foi maior na zona rural e na Zona urbana observou-se estreita relação entre esta e HMI. Nenhuma associação foi observada entre HMI, fatores socioeconômicos e história médica da mãe, no entanto, observou-se associação significativa com prematuridade (p= 0,01), icterícia/falta de oxigênio pós-parto (p=0,04). A HMI apresenta-se como grave problema para as crianças afetadas e profissional de saúde, devido à complexidade dos sinais e sintomas apresentados, sendo necessária realização de estudos prospectivos para elucidação da etiologia. / Abstract: With the purpose of identifying the relationship between dental caries and possible etiologic factors, prevalence, severity of molar-incisor hypomineralization (MIH), 1,124 schoolchildren from rural and urban area in Manaus, Amazonas, were examined. We used the criteria established EAPD and to diagnose MIH and the DMFT and deft indices to diagnose dental caries. A semi-structured questionnaire was completed by the mothers to investigate gestational health and the child's health during the first years of life, as well as the socioeconomic and demographic factors. Data were tabulated and analyzed using descriptive statistics and the chi-square test, Mann-Whitney test, backward method, and odds ratio were used to correlate the variables. The prevalence of MIH in Manaus was 8.9%, not being related to housing area, gender or age of the children diagnosed (p>0,05). Dental alteration was more frequently observed in the lower arch and the first molars were the most affected. The most frequent diagnosis was mild severity. Dental caries experience was higher in rural areas, but in Urban area there was a close relationship between this and the HMI. No association was observed among MIH, socioeconomic factors, and the medical history of the mother, however, a significant association was found among prematurity (p = 0.01), jaundice or lack of oxygen after birth (p = 0.04). MIH is a severe problem for both the children affected and the health professionals due to the complex signs and symptoms, requiring prospective studies to elucidate the etiology. / Doutor

Resumo: O objetivo foi avaliar a capacidade de géis com baixa concentração de F suplementados com trimetafosfato de sódio (TMP), em reduzir a desmineralização (in vitro) e promover a remineralização (in situ) de esmalte dentário. No estudo in vitro, blocos de esmalte bovino (n = 160) selecionados pela dureza de superfície (SHi) foram divididos em oito grupos de géis (n=20): sem F e TMP (Placebo); TMP3%, TMP5%; 4500 μg F/g (4500); 4500 μg F/g + TMP3% (4500 TMP3%), 4500 μg F/g + TMP5% (4500 TMP5%), 9000 μg F/g (9000) e 12300 μg F/g (Gel ácido). Os blocos foram submetidos a ciclagem de pH durante cinco dias, após aplicação tópica dos géis. A seguir, determinou-se a dureza de superfície final (SHf), perda integrada de dureza de subsuperfície (ΔKHN), CaF2, F, Ca, P formados e retidos no esmalte. Os resultados foram submetidos à análise de variância e teste de Bonferroni (p<0,05). Os grupos 4500 TMP5% e Gel ácido apresentaram a menor perda mineral (SHf e DKHN) e similares entre si (p>0,05). O Gel ácido apresentou a maior concentração de CaF2 formado. O grupo 4500 TMP5% apresentou o maior valor de F formado (p<0,05). O Gel ácido apresentou maiores valores de Ca retido (p<0,05), seguido pelos grupos 4500 TMP5% e 9000, que foram similares entre si (p>0,05). O P formado foi semelhante entre os grupos (p>0,05) e o Gel ácido apresentou a maior concentração de P retido no esmalte. Concluiu-se que é possível inibir a desmineralização do esmalte com gel fluoretado de baixa concentração suplementado-o com TMP. Para o estudo in situ, blocos de esmalte bovinos (n=240) foram selecionados pela dureza de superfície (SH1), após desmineralização, e divididos em cinco grupos experimentais: Placebo, 4500, 4500 TMP5%, 9000 e Gel ácido. Doze voluntários utilizaram dispositivos palatinos, com quatro blocos de esmalte desmineralizados, durante três ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the capacity of gels with low concentration of F supplemented with sodium trimetaphosphate (TMP) to reduce the dental enamel demineralization (in vitro) and remineralization (in situ). In the in vitro study blocks of bovine enamel (n=160) were selected through surface hardness (SHi) and divided into eight groups (n = 20): gel without F and TMP (Placebo), TMP3%, TMP5%, 4500 μg F/g (4500), 4500 μg F/g + TMP3% (4500 TMP3%), 4500 μg F/g + TMP5% (4500 TMP5%), 9000 μg F/g (9000) and 12.300 μg F/g (acid gel). The blocks were submitted to pH cycling during five days after topical application of gels. After that, the surface hardness (SHf), the subsurface hardness integrated loss (ΔKHN), CaF2, F, Ca and P formed and retained in enamel were determined. The results were submitted to analysis of variance and Bonferroni tests (p <0.05). Groups 4500 TMP5% and acid gel were similar and showed the best results for SHf and ΔKHN. The acid gel showed the highest concentration of CaF2 formed. The 4500 TMP5% group presented the highest values of F formed (p <0.05). The acid gel had the highest Ca retention (p <0.05), followed by 4500 TMP5% and 9000 groups, which were similar (p> 0.05). The P formed was similar between the groups (p> 0.05) and the acid gel showed the highest concentration of P retained in enamel. It was concluded that it is possible to inhibit enamel demineralization with low F concentration gel by supplementing it with TMP 5%. In the in situ study bovine enamel blocks (n=240) were selected through surface hardness (SH1) after demineralization and divided into five groups: Placebo, 4500, 4500 TMP5%, 9000 and Acid gel). Twelve volunteers wore palatal appliances with four demineralized blocks, during three days after topical application of F (ATF). Two blocks were removed immediately after the ATF to ... (Complete abstract click electronic access below) / Orientador: Alberto Carlos Botazzo Delbem / Coorientador: Kikue Takebayashi Sassaki / Banca: Sandra Helena Penha de Oliveira / Banca: Cínthia Pereira Machado Tabchoury / Mestre

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / The aim of this study was to evaluate the effectiveness of three mechanical methods for removal of demineralized dentin. A total of thirty sound human third molars indicated for extraction. After extraction, the teeth were cleaned and stored properly. The occlusal enamel was removed with a diamond wheel to expose a flat dentin surface, and each tooth was sectioned longitudinally in the buccal-lingual direction. One half of each tooth was entirely covered with an acid-resistant varnish, except for an occlusal area of 16 mm2, and was submitted to pH-cycling model to produce demineralized dentin. The other half of each tooth was maintained with mineralized dentin. The pH-cycling procedure was taken in 8 days. Halves of teeth were reassembled with cyanoacrylate adhesive. Samples were randomly allocated into three groups according to the method of removal of demineralized dentin: G1 â steel bur, G2 â polymer bur; G3 â hand excavation. The procedure of demineralized dentin removal was performed by a single operator. Digital images were obtained and cavities depths were measured (Âm) using MacBiophotonics ImageJ software. Knoop microhardness measurements (kgf/mm2) were performed in all samples at 10 to 200 Âm depth from the bottom of cavities. Data for cavity depth and microhardness were analyzed using One-Way ANOVA and the post hoc tests (p<0.05). The steel bur provided a larger wear, resulting in a deeper depth after the removal of the demineralized dentin, followed by the hand excavator and the polymer bur had a lower depth. The hardness values obtained with the steel bur were higher, indicating that there was a higher standard of demineralized dentin removal, followed by the hand excavator. The use of polymer bur left dentin with low values of hardness, indicating that demineralized tissue still remained. The polymer bur looks to be more selective in the removal of the demineralized dentin when compared with the steel bur and the hand excavator. / O objetivo do estudo foi avaliar a efetividade de trÃs mÃtodos mecÃnicos na remoÃÃo de dentina desmineralizada. Utilizaram-se 30 terceiros molares humanos hÃgidos, indicados para extraÃÃo. ApÃs a extraÃÃo, os dentes foram devidamente limpos e armazenados. Removeu-se o esmalte oclusal com um disco de diamante para expor uma superfÃcie plana de dentina e seccionou-se cada dente longitudinalmente, no sentido vestÃbulo-lingual. Uma metade de cada dente foi totalmente coberta com um verniz Ãcido resistente, com exceÃÃo de uma Ãrea oclusal de 16 mm2, e submetida à ciclagem de pH para produzir dentina desmineralizada. A outra metade de cada dente foi mantida com a dentina mineralizada. A dentina desmineralizada foi criada por meio de procedimento de ciclagem de pH durante 8 dias. As metades dos dentes foram unidas novamente com adesivo de cianoacrilato. Alocaram-se aleatoriamente as amostras em trÃs grupos, segundo o mÃtodo de remoÃÃo da dentina desmineralizada: G1 â broca de aÃo esfÃrica; G2 â broca de polÃmero; G3 â cureta de dentina. Um Ãnico operador realizou o procedimento de remoÃÃo de dentina desmineralizada. ApÃs a remoÃÃo da dentina, as metades dos dentes foram separadas, incluÃdos em resina acrÃlica e polidas. As imagens digitais foram obtidas e as profundidades das cavidades foram medidas (Âm) com o uso do programa MacBiophotonics ImageJ. Realizaram-se medidas de dureza Knoop (kgf/mm2) em todas as amostras de 10 a 200 microns a partir do fundo das cavidades. Os dados de profundidade da cavidade e microdureza foram analisados utilizando One-Way ANOVA e os testes post hoc (p<0,05). A broca de aÃo proporcionou um maior desgaste, resultando em uma maior profundidade apÃs a remoÃÃo da dentina desmineralizada, seguida da cureta de dentina, e a broca de polÃmero teve uma menor profundidade. Os valores de dureza obtidos com o emprego da broca de aÃo foram maiores, o que indica que houve um padrÃo maior de remoÃÃo de dentina desmineralizada, seguidos dos valores da cureta de dentina, enquanto a broca de polÃmero apresentou nÃmeros menores de dureza, apontando ainda a presenÃa de tecido desmineralizado. A broca de polÃmero parece ser mais seletiva na remoÃÃo da dentina desmineralizada, quando comparada com a broca de aÃo e a cureta de dentina.

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.