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Desproteinização da dentina e o seu efeito nas propriedades de superfície : ensaio de microespectroscopia de Raman e microscopia eletrónica de varrimento
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Advisor(s)
Abstract(s)
Objetivos: Avaliar, in vitro, se a utilização de ácido hipocloroso em associação com cloreto de estrôncio (HOCl+SrCl2), após condicionamento ácido, induz diferenças nas propriedades superficiais e na superfície topográfica da dentina e, comparar as potenciais diferenças com o hipoclorito de sódio (NaOCl), através da microespectroscopia de Raman e microscopia eletrónica de varrimento (MEV), respetivamente.
Materiais e Métodos: Para o presente estudo, 15 molares humanos hígidos foram aleatoriamente distribuídos por 3 grupos experimentais (n=5): o grupo NaOCl (controlo positivo), o grupo H2O (controlo negativo) e o grupo HOCl+SrCl2 (grupo teste). Cada molar foi seccionado num micrótomo de tecidos duros a fim de se obter discos de dentina coronal média. Nos três grupos, a dentina foi condicionada com ácido ortofosfórico a 37% durante 15 s e lavagem durante 30 s. Após condicionamento ácido, os grupos foram submetidos aos
seguintes procedimentos: grupo NaOCl – aplicação de uma solução de NaOCl a 13% durante 60 s e lavagem durante 60 s; grupo H2O - apenas lavagem abundante; grupo HOCl+SrCl2 –
aplicação de 105 ppm de HOCl e 0.4 M de SrCl2 durante 30 s, e lavagem durante 30 s. Depois
de aplicados os agentes, os grupos foram armazenados em água destilada a 37ºC. Após
armazenamento foram analisadas 2 amostras aleatórias de cada grupo experimental, no
microscópio eletrónico de varrimento, para avaliação da superfície topográfica da dentina, e 3
amostras de cada grupo na microespectroscopia de Raman para avaliação das propriedades de
superfície da dentina, tais como a componente mineral e colagénica, através de espetros como
do fosfato e amidas (I, II e III), respetivamente. Os dados foram analisados estatisticamente
através do teste ANOVA one-way com post-hoc Tukey (p<0,01), a um nível de significância
de 5%.
Resultados: Através de MEV, foi possível verificar que no grupo H2O a superfície dentinária
encontra-se menos irregular que a superfície do grupo NaOCl, que se mostra rugosa e porosa.
Na superfície do grupo HOCl+SrCl2, embora pouco evidente, houve um aumento do número
de túbulos dentinários e uma diminuição da dentina intertubular. Através de micro-Raman, os
resultados demonstram que apenas o NaOCl teve um efeito significativo na degradação da
matriz de colagénio, com um aumento da razão mineral/matriz (RM/M).
Conclusões: O NaOCl mostrou ser capaz de efetuar depleção do colagénio bem como alterar
a superfície topográfica da dentina. O HOCl+SrCl2, não mostrou ser capaz de efetuar depleção
do colagénio, mesmo tendo sido capaz de provocar algumas alterações topográficas na dentina.
Objectives: To evaluate, in vitro, whether the use of hypochlorous acid in association with strontium chloride (HOCl+SrCl2), after acid etching, induces differences in the surface properties and topographic surface of dentin and to compare the potential differences with sodium hypochlorite (NaOCl), using Raman micro-spectroscopy and scanning electron microscopy (SEM), respectively. Materials and Methods: For this study, 15 healthy human molars were randomly assigned to 3 experimental groups (n=5): the NaOCl group (positive control), the H2O group (negative control) and the HOCl+SrCl2 group (test group). Each molar was sectioned using a hard tissue microtome to obtain discs of middle coronal dentin. In both groups, the dentin was etched with 37% orthophosphoric acid for 15 seconds and rinsed for 30 seconds. After acid etching, the NaOCl group was treated with a 13% NaOCl solution for 60 s and rinsed for 60 s; the H2O group was only thoroughly rinsed; and the HOCl+SrCl2 group was treated with 105 ppm HOCl and 0.4 M SrCl2 for 30 s, and rinsed for 30 s. After applying the agents, the groups were stored in distilled water at 37ºC. After storage, 2 random samples from each experimental group were analyzed using a scanning electron microscope to assess the topographic surface of the dentin; and 3 samples from each group were analyzed using Raman microspectroscopy to assess the surface properties of the dentin, such as the mineral and collagen component using spectra such as phosphate and amides (I, II and III), respectively. The data was statistically analyzed using the one-way ANOVA test with Tukey post-hoc (p<0.01), at a significance level of 5%. Results: The SEM showed that the dentin surface of the H2O group was less irregular than that of the NaOCl group, which was rough and porous. On the surface of the HOCl+SrCl2 group, although not very evident, there was an increase in the number of dentinal tubules and a decrease in intertubular dentin. Using micro-Raman, the results show that only NaOCl had a significant effect on the degradation of the collagen matrix, with an increase in the mineral/matrix ratio (RM/M). Conclusions: The traditional NaOCl irrigant proved being able to deplete collagen and alter the topographic surface of dentin. Conversely, HOCl+SrCl2 was not able to entirely deplete the collagen network, although it was able to cause some topographical changes in the dentin.
Objectives: To evaluate, in vitro, whether the use of hypochlorous acid in association with strontium chloride (HOCl+SrCl2), after acid etching, induces differences in the surface properties and topographic surface of dentin and to compare the potential differences with sodium hypochlorite (NaOCl), using Raman micro-spectroscopy and scanning electron microscopy (SEM), respectively. Materials and Methods: For this study, 15 healthy human molars were randomly assigned to 3 experimental groups (n=5): the NaOCl group (positive control), the H2O group (negative control) and the HOCl+SrCl2 group (test group). Each molar was sectioned using a hard tissue microtome to obtain discs of middle coronal dentin. In both groups, the dentin was etched with 37% orthophosphoric acid for 15 seconds and rinsed for 30 seconds. After acid etching, the NaOCl group was treated with a 13% NaOCl solution for 60 s and rinsed for 60 s; the H2O group was only thoroughly rinsed; and the HOCl+SrCl2 group was treated with 105 ppm HOCl and 0.4 M SrCl2 for 30 s, and rinsed for 30 s. After applying the agents, the groups were stored in distilled water at 37ºC. After storage, 2 random samples from each experimental group were analyzed using a scanning electron microscope to assess the topographic surface of the dentin; and 3 samples from each group were analyzed using Raman microspectroscopy to assess the surface properties of the dentin, such as the mineral and collagen component using spectra such as phosphate and amides (I, II and III), respectively. The data was statistically analyzed using the one-way ANOVA test with Tukey post-hoc (p<0.01), at a significance level of 5%. Results: The SEM showed that the dentin surface of the H2O group was less irregular than that of the NaOCl group, which was rough and porous. On the surface of the HOCl+SrCl2 group, although not very evident, there was an increase in the number of dentinal tubules and a decrease in intertubular dentin. Using micro-Raman, the results show that only NaOCl had a significant effect on the degradation of the collagen matrix, with an increase in the mineral/matrix ratio (RM/M). Conclusions: The traditional NaOCl irrigant proved being able to deplete collagen and alter the topographic surface of dentin. Conversely, HOCl+SrCl2 was not able to entirely deplete the collagen network, although it was able to cause some topographical changes in the dentin.
Description
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Keywords
Camada híbrida Dentina Desproteinização Irrigantes endodônticos