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Análise laboratorial de dentina tratada com plasma não térmico atmosférico utilizando espectroscopia de infravermelho por transformada de Fourier (ATR-FTIR)
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Objetivos: O objetivo deste estudo in vitro é avaliar o efeito do plasma atmosférico não térmico (NTAP) na superfície da dentina, em diferentes tempos, utilizando a espectroscopia de infravermelhos por transformada de Fourier em técnica de refletância atenuada total (ATR-FTIR).
Materiais e Métodos: Foram utilizados 7 molares humanos saudáveis, dos quais se seccionou uma fatia de dentina coronal de 3,5mm. Sobre a superfície da dentina foi aplicado NTAP utilizando uma caneta de plasma de árgon a 2mm da dentina durante 10s. Todas as amostras foram analisadas por ATR-FTIR, nos tempos T0, T10min, T1h, T24h, utilizando o acessório de cristal ATR e o modo Sprectrum do software Shimadzu LabSolutions IR. Os espectros foram adquiridos na faixa de 4000-400cm-1, com uma resolução espectral de 2cm-1 e 32 scans por medição, no modo de absorvância. As análises estatísticas foram realizadas em Python 3.11. Os resultados do ATR-FTIR e as rácios derivados foram comparados ao longo do tempo com o teste de Friedman e o W de Kendall como medida do tamanho do efeito. A correção FDR de Benjamini-Hochberg foi aplicada para comparações múltiplas, e a significância foi definida em α = 0,05.
Resultados: A análise de medidas repetidas, imediatamente, após 10min, 1h e 24h, em comparação com o grupo de controlo (n=7), não revelou alterações significativas dependentes do tempo nos parâmetros da dentina relacionados com a fase mineral após o tratamento com NTAP. As variações temporais mais pronunciadas foram observadas nas regiões espectrais orgânicas. Contudo, os efeitos devem ser interpretados como tendências temporais.
Conclusão: A análise por ATR-FTIR demonstrou modificações transitórias que afectam predominantemente a fase orgânica da dentina, com os decréscimos mais distintos a ocorrerem passado 60min e regressão parcial às 24h. Os resultados sugerem uma resposta dependente do tempo relevante, com alterações transitórias e alterações sustentadas.
Objectives: The aim of this in vitro study is to evaluate the effect of non-thermal atmospheric plasma (NTAP) on the dentin surface at different time points, using Fourier-transform infrared spectroscopy with the attenuated total reflection (ATR-FTIR) technique. Materials and Methods: Seven healthy human molars were used, from wich a 3.5mm coronal dentin slice was sectioned. NTAP was applied to the dentin surface using as argon (99% purity, air liquid) plasma pen in continuous mode 4-6L/min, 2mm from the dentin during 10s. All specimens were analysed by ATR-FTIR at baseline (T0), 10min (T10min), 1h (T1h), and 24h (T24h) using ATR crystal accessory and the Spectrum mode of Shimadzu LabSolutions IR software. Sprectra were acquired over the 4000-400cm-1 range, with a spectral resolution of 2cm-1 and 32 scans per measurement, in absorbance mode. Statistical analyses were performed in Python 3.11. ATR-FTIR outcomes and derived ratios were compared over time using the Friedman test, with Kendall’s W as the effect-size measure. Benjamini-Hochberg false discovery rate correction was applied for multiple comparisons, and significance was set at α = 0,05. Results: Repeated-measures analysuis across baseline, immediate, 10min, 1h, 24h time points (n=7) revealed no significant time-dependent changes in dentin parameters associated with the mioneral phase following NTAP treatment. The most pronounced temporal variations were observed in the organi spectral regions. However, the findings should be interpreted as temporal trens rather thans statistically significant effects. Conclusion: ATR-FTIR analçysis demonstrated transiet modifications predominantly affecting the organic phase of dentin, with the most marked dreases occuring at 1h and a persistente effect observed afeter 24h. These findings indicate biologically relevant time-dependent reposnse characterised by both transiente modifications and partial regression alterations.
Objectives: The aim of this in vitro study is to evaluate the effect of non-thermal atmospheric plasma (NTAP) on the dentin surface at different time points, using Fourier-transform infrared spectroscopy with the attenuated total reflection (ATR-FTIR) technique. Materials and Methods: Seven healthy human molars were used, from wich a 3.5mm coronal dentin slice was sectioned. NTAP was applied to the dentin surface using as argon (99% purity, air liquid) plasma pen in continuous mode 4-6L/min, 2mm from the dentin during 10s. All specimens were analysed by ATR-FTIR at baseline (T0), 10min (T10min), 1h (T1h), and 24h (T24h) using ATR crystal accessory and the Spectrum mode of Shimadzu LabSolutions IR software. Sprectra were acquired over the 4000-400cm-1 range, with a spectral resolution of 2cm-1 and 32 scans per measurement, in absorbance mode. Statistical analyses were performed in Python 3.11. ATR-FTIR outcomes and derived ratios were compared over time using the Friedman test, with Kendall’s W as the effect-size measure. Benjamini-Hochberg false discovery rate correction was applied for multiple comparisons, and significance was set at α = 0,05. Results: Repeated-measures analysuis across baseline, immediate, 10min, 1h, 24h time points (n=7) revealed no significant time-dependent changes in dentin parameters associated with the mioneral phase following NTAP treatment. The most pronounced temporal variations were observed in the organi spectral regions. However, the findings should be interpreted as temporal trens rather thans statistically significant effects. Conclusion: ATR-FTIR analçysis demonstrated transiet modifications predominantly affecting the organic phase of dentin, with the most marked dreases occuring at 1h and a persistente effect observed afeter 24h. These findings indicate biologically relevant time-dependent reposnse characterised by both transiente modifications and partial regression alterations.
Descrição
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Palavras-chave
ATR Dentina FTIR Plasma não térmico atmosférico