Difusão do ácido cítrico e do seu efeito erosivo na desmineralização do esmalte dentário

• Autor(a) principal: Medeiros, Isabella Cavalcante
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/11640
• topic: Erosão dentária; Testes de dureza; Absorção atômica; Microscopia de polarização; Espectrofotometria; Dental erosion; Hardness tests; Atomic absorption; Polarization microscopy; Spectrophotometry; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA

The aim of this study was to investigate the diffusion of citric acid (0.1 M - pH 2.27) in enamel structure and its potential to demineralizate enamel and dentin by Vickers Microhardness (VHN) and immediate and later release of calcium ions (Ca+2) and phosphate (PO4-3). Thirty third sound and non-erupted molars were used. The samples were divided randomly into 3 groups (n = 10) for the following analysis: Polarized light microscopy (MLP); Atomic absorption spectroscopy and spectrophotometry to assess the immediate and later release of Ca+2 and PO4-3 ions, respectively; and VHN of surface and deep into the enamel and dentin. For MLP analysis, the samples were prepared to a thickness of 100 µm, the erosive agent was applied from the enamel surface and photographic records were performed for 5 h during the diffusion of citric acid in the enamel by MPL using the single PolScope. For VHN, enamel blocks (4 × 4 mm) were prepared and divided (2 x 4 mm) into experimental and control groups. The area of control group was isolate with nail varnish. The samples were subjected to erosive challenge for 10 min. The superficial VHN was made before and after the erosive challenge. Then, the samples were sectioned at the interface between control and experimental groups for deep VHN analysis. VHN analysis through enamel were measured to 40 µm until 1000 µM of depth. For dentin the measurements were carried out between 00 µm to 360 µm of dentinoenamel junction (DEJ). For the quantification of Ca+2 and PO4-3 ions in the erosive solution (for immediate and later analysis), 5 mL of the solution was used for each ion analysis. For the later release analysis, the samples were immersed in 10 mL of deionized water (pH 6.5) during 48 h for analysis. Data were analyzed by t test and Wilcoxon, a = 0.05. The VHN of surface and deep analysis of enamel showed reduction of VHN values after the erosive challenge. For dentin, there also was reduction of VHN values until 120 µm of DEJ. There was higher release of Ca+2 ions immediately after the erosive challenge when compared to the control group, but there was no difference for later release analysis. In contrast, there was increased release of PO4-3 ions in the later analysis, and no difference with the control in the analysis of immediate release. The MLP analysis revealed a difference in the phase delay of dental enamel after erosive challenge, thus, the erosive diffusion occurred throughout the depth of enamel. It was concluded that the citric acid had continuous diffusion through enamel structure until DEJ and caused demineralization in dentin until 120 µm.