Effect of anti-erosive agents : in situ study under normal and hyposalivatory conditions and in vitro study changing the viscosity of an experimental compound

Orientador: Debora Alves Nunes Leite LimaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Esse estudo avaliou a eficácia de diferentes agentes anti-erosivos in situ, variando o fluxo salivar (Capítulo 1); e, in vitro, frente aos desafios erosivo e erosivo/abrasivo (Capítulo 2). O estudo In situ, crossover e duplo-cego, utilizou amostras de esmalte bovino (4x4mm) em 4 fases experimentais (4h/cada) de acordo com os dentifrícios: placebo (Controle), fluoreto de sódio (NaF: 1400 ppm), fluoreto de estanho (SnF/NaF: 1100 ppm-SnF2, 300 ppm-NaF) e quitosana (NaF/Sn/Ch: 1450 ppm-NaF, 3500 ppm-SnCl2, 0,5% quitosana). Vinte voluntários foram divididos em 2 amostras (n=10), fluxo salivar normal ou reduzido, sendo cada voluntário um bloco estatístico. Os espécimes foram submetidos à erosão com ácido cítrico 1% (pH 3,5) previamente (Desmineralização 1 ¿ D1) e após (D2) a exposição ao meio bucal. A microdureza foi analisada inicialmente, após D1, após o período in situ e após D2, para análise dos parâmetros %SMH (perda de dureza superficial), %SMR (recobrimento de dureza superficial) e %RER (resistência relativa à erosão). O fluxo, pH e capacidade tampão salivar foram analisados em todas as fases experimentais. No estudo in vitro, espécimes de esmalte humano (3x2mm) foram submetidos a desmineralização (Ácido cítrico 0,5%, 2 min/6x/10 dias) e remineralização, sem (Experimento 1) ou com (Experimento 2) escovação. Após a primeira e última erosão diárias, as amostras foram tratadas com diferentes soluções contendo quitosana ou não ¿ 6 grupos: Ch50, Ch500, Ch1000, Ch2000 (0,5%) associados a flúor (500 ppm¿AmF) e estanho (800 ppm¿SnCl2), controle positivo (sem quitosana) e negativo (sem tratamento). No Experimento 2, as amostras foram escovadas (15s) com dentifrício não fluoretado previamente ao tratamento com soluções. As amostras foram analisadas com perfilometria (n=16), análise por energia dispersiva de raios-X (EDX/n=10) e por microscopia eletrônica de varredura (MEV/n=4). Ambos os estudos foram analisados estatisticamente por análise de variância (ANOVA) e testes post-hoc, além de análise de correlação de Pearson (Estudo in situ) (?=5%). No estudo in situ, o dentifrício SnF/NaF apresentou o melhor desempenho, seguido pelo NaF/Sn/Ch, NaF e placebo, sob fluxo salivar normal (p0,05), que apresentaram o melhor resultado, e entre o NaF e o placebo (p>0,05). A análise de Pearson evidenciou correlação entre alguns dentifrícios e o fluxo salivar para %SMR e %RER. No estudo in vitro, as soluções com quitosana foram eficientes em reduzir o desgaste do esmalte. No Experimento 1, o Ch2000 preveniu totalmente a perda de tecido, formando precipitados sobre o esmalte (p0.05), which presented the best results; and between NaF and placebo (p>0.05). Pearson¿s analysis showed significant correlations between some toothpastes and salivary flow for %SMR and %RER. In the in vitro study, the Ch-based solutions were efficient in reducing enamel loss. In Experiment 1, Ch2000 totally prevented enamel loss with the formation of some precipitates under the enamel (p<0,05), which was observed by SEM analysis. EDX showed increase in stannous content for the experimental groups, without statistical differences between them. In the Experiment 2, Ch50 and Ch2000 presented the best results for enamel loss, which was also verified in the SEM analysis. The Ch-based solutions, excluding Ch500, resulted in higher deposition of stannous under enamel with differences in relation to the positive control. Chitosan may be a promisor active agent to be used, once it showed its ant-erosive action in both studiesDoutoradoDentísticaDoutora em Clínica OdontológicaCAPE

Avaliação in vitro e in situ da técnica de microabrasão sobre a microdureza e morfologia do esmalte dental

Orientadores: José Roberto Lovadino, Débora Alves Nunes Leite LimaTexto em português e inglêsDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Objetivo: Avaliar, in vitro, a influência dos ácidos utilizados para microabrasão e, in situ, o efeito do tempo de contato com a saliva na microdureza e morfologia do esmalte abrasionado. Metodologia: In vitro: Setenta blocos dentais bovinos foram divididos em 7 grupos (n=10). Os grupos experimentais foram tratados com aplicação ativa/passiva dos ácidos H3PO4 35% (E1/E2) ou HCl 6,6% (E3/E4); e controles, tratados com microabrasão com H3PO4+pedra-pomes (C5), HCl+silica (C6) ou nenhum tratamento (C7). In situ: Nove grupos (n=19) de blocos dentais bovinos foram divididos de acordo com o tratamento e o tempo de exposição salivar, sendo 4 grupos tratados com H3PO4+pedra-pomes, 4 com HCl+sílica e 1 grupo controle. Os grupos tratados foram subdivididos em: sem exposição salivar, 1 hora, 24 horas ou 7 dias de exposição em ambiente intrabucal. A microdureza superficial (SMH) foi avaliada antes e após a microabrasão, e após exposição salivar (in situ). A microdureza subsuperficial (CSMH - 10, 25, 50 e 75 ?m) foi analisada após a microabrasão (in vitro) e após a exposição salivar (in situ). Espécimes representativos foram selecionados para a avaliação da morfologia do esmalte por meio da microscopia confocal de varredura a laser (MCVL - in vitro) e por microscopia eletrônica de varredura (MEV - in situ). Para a análise estatística foi realizada análise de variância para medidas repetidas (Proc Mixed), e os testes de Tukey-Kramer e Dunnet (SMH) e ANOVA (parcelas subdivididas) e Tukey-Kramer (CSMH - in situ) (p<0.05). Resultados: In vitro: Não foram encontradas diferenças entre as análises pré e pós-microabrasão entre os grupos controles para SMH. Entre os grupos experimentais, a aplicação ativa demonstrou os maiores valores de SMH, sem diferença entre os ácidos, com a mesma forma de aplicação. A maioria dos grupos apresentou redução do valor de CSMH conforme aumento da profundidade, com diferenças entre os grupos com microabrasão (C5 e C6) e o C7; e entre todos os grupos experimentais e o C7. Comparando a aplicação dos ácidos, a aplicação ativa do H3PO4 (E1) mostrou maior CSMH com diferença estatística em relação ao HCl (E3). A MCVL demonstrou diferentes padrões de condicionamento para cada grupo. In situ: Para as análises de SMH, todos os grupos tratados apresentaram redução na microdureza, com diferenças em relação ao controle e a leitura inicial. Após exposição salivar, os resultados demonstraram que o tratamento com HCl+sílica foi mais propenso à remineralização, já que, com 1 hora foi verificado aumento na SMH, com diferença significante em relação à análise pós-microabrasão. Apenas o tratamento com HCl+sílica foi eficiente em reestabelecer tal propriedade em relação ao controle. A análise de CSMH confirmou a maior capacidade de remineralização do esmalte tratado com HCl+sílica, uma vez que após 7 dias de exposição salivar, os valores de microdureza foram restabelecidos para as camadas mais superficiais do esmalte (10 e 25 ?m). A MEV demonstrou o efeito remineralizador da saliva para ambos os tratamentos. Conclusões: Os ácidos utilizados para microabrasão apresentaram alto poder erosivo quando aplicados individualmente. O tratamento com HCl+sílica resultou em uma superfície de esmalte mais propensa à remineralizaçãoAbstract: Objective: To evaluate, in vitro, the effect of acids used in microabrasion on enamel microhardness, and, in situ, the effects of remineralizing time on enamel surface after microabrasion. Methods: In vitro: Seven groups (n=10) of enamel blocks from bovine incisors were divided in: Experimental groups treated by active/passive application of 35% H3PO4 (E1/E2) or 6.6% HCl (E3/E4); and control groups treated by microabrasion with H3PO4+pumice (C5), HCl+silica (C6), or no treatment (C7). In situ: Nine groups (n=19) of same specimens were divided in according to microabrasion and salivary exposition being 1 control (no treatment) and 4 groups with microabrasion using 35% H3PO4+pumice and 4 groups using 6.6% +silica. One group of each treatment was submitted to 4 frames of salivary exposition, being without exposition and with 1 hour, 24 hours or 7 days of presence on in situ regimen. Surface microhardness (SMH) was evaluated before and after microabrasion, and after salivary exposition (in situ). Cross-sectional microhardness (CSMH) was analyzed after microabrasion (in vitro) and after salivary exposition (in situ). For confocal laser scanning microscopy (CLSM - in vitro) and scanning electron microscopy (SEM - in situ), representative specimens group were selected. Statistical analysis used Proc Mixed, Tukey-Kramer and Dunnet tests (SMH) e ANOVA (subdivided parcels) and Tukey-Kramer tests (CSMH - in situ) (p<0.05). Results: In vitro: For SMH, it was not found statistically differences between the control groups after treatment. Active application resulted in significantly higher microhardness results than passive application, with no difference between acids. For most groups, the CSMH decreased as the depth increased, with differences between the groups treated with microabrasion (C5 and C6) and C7; and between all of experimental groups and C7. A significantly higher mean CSMH result was obtained with active application of H3PO4 compared to HCl. CLSM revealed the conditioning pattern for each group. In situ: For SMH, the groups treated with microabrasion presented reducing in mineral content, with statistical difference in relation to the control and to the initial analysis. The treatment HCl+silica presented lower reduction and were statistically different from the treatment with H3PO4+pumice. After salivary exposition SMH results revealed that surface treated with HCl+silica was more prone to remineralizing effect of saliva, once it was verified since with 1 hour of presence in in situ regimen, with significant differences between the treatments after 7 days of salivary exposition. Just for SMH, the HCl+silica reached values obtained in control group. CSMH analysis showed that 7 days of salivary exposition were efficient in reestablish de values for the outer layers (10 e 25 ?m) of enamel treated with HCl+silica. SEM analysis presented the remineralizing effect in the course of the time. Conclusions: Acids used for enamel microabrasion presented a higher erosive action when solely applicated. Data suggested that enamel surface treated with HCl+silica presented more susceptibility for remineralizing action of saliva than that treated with phosphoric acid and pumiceMestradoDentísticaMestra em Clínica Odontológic

In situ assessment of the saliva effect on enamel morphology after microabrasion technique

AIM: This study evaluated saliva effects on enamel morphology surface after microabrasion technique. METHODS: Enamel blocks (16 mm2) obtained from bovine incisors were divided into 9 groups as follows: one control group (no treatment), four groups with microabrasion treatment using 35% phosphoric acid and pumice (H3PO4+Pum) and other four groups treated with 6.6% hydrochloric acid and silica (HCl+Sil). One group of each treatment was submitted to 4 frames of saliva exposure: without exposure, 1-h exposure, 24-h exposure, and 7-days exposure on in situ regimen. Nineteen volunteers (n=19), considered as statistical blocks, used an intraoral appliance containing the specimens, for 7 days. Enamel roughness (Ra) was tested before and after treatment, and after saliva exposure. Confocal laser scanning microscopy (CLSM) was used to evaluate qualitatively the enamel morphology. RESULTS: All groups exhibited increased Ra after microabrasion. With regards to saliva exposure, the treatment with HCl+Sil presented more susceptibility to the saliva action, but no period of time was efficient in re-establishing this characteristic compared with the control group. CLSM analysis showed reduction of the micro-abrasive damages during the experimental times. CONCLUSIONS: Seven days of saliva exposure were not sufficient for the treated enamel to reach its normal characteristics compared with the control group133187192FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2011/004067-

Effects of acids used in the microabrasion technique: microhardness and confocal microscopy analysis

Background: This study evaluated the effects of the acids used in the microabrasion on enamel. Material and Methods: Seventy enamel/dentine blocks (25 mm 2 ) of bovine incisors were divided into 7 groups (n=10). Experimental groups were treated by active/passive application of 35% H 3 PO 4 (E1/E2) or 6.6% HCl (E3/ E4). Control groups were treated by microabrasion with H 3 PO 4 +pumice (C5), HCl+silica (C6), or no treatment (C7). The superficial (SMH) and cross-sectional (CSMH; depths of 10, 25, 50, and 75 μm) microhardness of enamel were analyzed. Morphology was evaluated by confocal laser-scanning microscopy (CLSM). Data were analyzed by analysis of variance (Proc Mixed), Tukey, and Dunnet tests (α=5%). Results: Active application (E1 and E3) resulted in higher microhardness than passive application (E2 and E4), with no difference between acids. For most groups, the CSMH decreased as the depth increased. All experimental groups and negative controls (C5 and C6) showed significantly reduced CSMH values compared to the control. A significantly higher mean CSMH result was obtained with the active application of H 3 PO 4 (E1) compared to HCl (E3). Passive application did not result in CSMH differences between acids. CLSM revealed the conditioning pattern for each group. Conclusions: Although the acids displayed an erosive action, use of microabrasive mixture led to less damage to the enamel layer

Effects of different toothpastes on the prevention of erosion in composite resin and glass ionomer cement enamel and dentin restorations

Objective:This study aimed to evaluate the effects of different toothpastes on the surface wear of enamel, dentin, composite resin (CR), and resin-modified glass ionomer cement (RMGIC), and to perform a topographic analysis of the surfaces, based on representative images generated by atomic force microscopy (AFM) after erosion-abrasion cycles. Methodology: One hundred and forty bovine incisors were collected and divided into two groups: 72 enamel and 72 dentin blocks (4×4 mm). Half of the specimens were restored with CR (Filtek Z350 XT) and the other half with RMGIC (Fuji II LC). Then, samples were submitted to a demineralization cycle (5 days, 4×2 min/day, 1% citric acid, pH 3.2) and exposed to three different toothpastes (2×15 s/day): without fluoride (WF, n=12), sodium fluoride-based (NaF, n=12), and stannous fluoride-based (SnF2, n=12). Surface wear, as well as restoration interfaces wear, were investigated by profilometry of the dental substrates and restorative materials. All representative surfaces underwent AFM analysis. Data were analyzed by two-way analysis of variance and Tukey’s tests (α=0.05). Results: NaF-based toothpaste caused the greater dentin surface wear (p&lt;0.05). Toothpastes affected only enamel-restoration interfaces. AFM analysis showed precipitate formation in dentinal tubules caused by the use of fluoride toothpastes. Conclusions: NaF-based toothpastes had no protective effect on enamel adjacent to CR and RMGIC against erosion-abrasion challenges, nor on dentin adjacent to RMGIC material. SnF2-based toothpastes caused more damage to interfaces between enamel and RMGIC

In situ assessment of the saliva effect on enamel morphology after microabrasion technique

AIM:This study evaluated saliva effects on enamel morphology surface after microabrasion technique.METHODS:Enamel blocks (16 mm2) obtained from bovine incisors were divided into 9 groups as follows: one control group (no treatment), four groups with microabrasion treatment using 35% phosphoric acid and pumice (H3PO4+Pum) and other four groups treated with 6.6% hydrochloric acid and silica (HCl+Sil). One group of each treatment was submitted to 4 frames of saliva exposure: without exposure, 1-h exposure, 24-h exposure, and 7-days exposure on in situ regimen. Nineteen volunteers (n=19), considered as statistical blocks, used an intraoral appliance containing the specimens, for 7 days. Enamel roughness (Ra) was tested before and after treatment, and after saliva exposure. Confocal laser scanning microscopy (CLSM) was used to evaluate qualitatively the enamel morphology.RESULTS:All groups exhibited increased Ra after microabrasion. With regards to saliva exposure, the treatment with HCl+Sil presented more susceptibility to the saliva action, but no period of time was efficient in re-establishing this characteristic compared with the control group. CLSM analysis showed reduction of the micro-abrasive damages during the experimental times.CONCLUSIONS:Seven days of saliva exposure were not sufficient for the treated enamel to reach its normal characteristics compared with the control group.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

In situ assessment of the saliva effect on enamel morphology after microabrasion technique

is study evaluated saliva effects on enamel morphology surface after microabrasion technique. Methods: Enamel blocks (16 mm2) obtained from bovine incisors were divided into 9 groups as follows: one control group (no treatment), four groups with microabrasion treatment using 35% phosphoric acid and pumice (H3PO4+Pum) and other four groups treated with 6.6% hydrochloric acid and silica (HCl+Sil). One group of each treatment was submitted to 4 frames of saliva exposure: without exposure, 1-h exposure, 24-h exposure, and 7-days exposure on in situ regimen. Nineteen volunteers (n=19), considered as statistical blocks, used an intraoral appliance containing the specimens, for 7 days. Enamel roughness (Ra) was tested before and after treatment, and after saliva exposure. Confocal laser scanning microscopy (CLSM) was used to evaluate qualitatively the enamel morphology. Results: All groups exhibited increased Ra after microabrasion. With regards to saliva exposure, the treatment with HCl+Sil presented more susceptibility to the saliva action, but no period of time was efficient in re-establishing this characteristic compared with the control group. CLSM analysis showed reduction of the micro-abrasive damages during the experimental times. Conclusions: Seven days of saliva exposure were not sufficient for the treated enamel to reach its normal characteristics compared with the control grou

In Vitro Effects Of Hydrogen Peroxide Combined With Different Activators For The In-office Bleaching Technique On Enamel.

Abstract Objective. The aim of this study was to evaluate the alteration of human enamel bleached with high concentrations of hydrogen peroxide associated with different activators. Materials and methods. Fifty enamel/dentin blocks (4 × 4 mm) were obtained from human third molars and randomized divided according to the bleaching procedure (n = 10): G1 = 35% hydrogen peroxide (HP - Whiteness HP Maxx); G2 = HP + Halogen lamp (HL); G3 = HP + 7% sodium bicarbonate (SB); G4 = HP + 20% sodium hydroxide (SH); and G5 = 38% hydrogen peroxide (OXB - Opalescence Xtra Boost). The bleaching treatments were performed in three sessions with a 7-day interval between them. The enamel content, before (baseline) and after bleaching, was determined using an FT-Raman spectrometer and was based on the concentration of phosphate, carbonate, and organic matrix. Statistical analysis was performed using two-way ANOVA for repeated measures and Tukey's test. Results. The results showed no significant differences between time of analysis (p = 0.5175) for most treatments and peak areas analyzed; and among bleaching treatments (p = 0.4184). The comparisons during and after bleaching revealed a significant difference in the HP group for the peak areas of carbonate and organic matrix, and for the organic matrix in OXB and HP+SH groups. Tukey's analysis determined that the difference, peak areas, and the interaction among treatment, time and peak was statistically significant (p < 0.05). Conclusion. The association of activators with hydrogen peroxide was effective in the alteration of enamel, mainly with regards to the organic matrix.1-