Síntese, caracterização e avaliação do potencial anticariogênico in vitro de Hidróxidos duplos lamelares fluoretados (Mg, Al - F HDL)

• Autor(a) principal: Cardoso , Clarissiane Serafim
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal de Alagoas (UFAL)
• Texto Completo: http://www.repositorio.ufal.br/handle/riufal/2983
• topic: Nanotecnologia; Flúor; Cárie dentária; Nanotechnology; Fluorine; Dental caries; CNPQ::CIENCIAS DA SAUDE

Dental caries is a multifactorial disease with S. mutans as the main etiological agent. Fluoride (F-), in turn, stands out in the prevention of this disease in a remineralizing and antimicrobial way.Thus, the synthesis of layered double hydroxides fluoride - Mg, Al - F HDL aims at the possibility of combining these elements, arranged in nanoscale lamellae, to evaluate their anticariogenic potential. The aim of the present study was the synthesis, characterization, in vitro, and microbiological evaluation of layered double hydroxides (HDLs) fluoride (Mg, Al-F HDL), aiming the prevention of dental caries. The synthesis of these products followed the ion exchange method from a precursor HDL containing chloride as interlamellar anion (Mg, Al - Cl HDL) in three variations: 1) micrometric – group 1, 2) nanometric colloidal suspension – group 2 and 3) nanometric resulting powder – group 3. The following parameters were analyzed: agitation time (2 and 24h) and temperature (25 and 40 ° C), obtaining the following products: Mg, Al - F HDL - F 2h25 ° C; Mg, Al-F HDL-F 24h25 ° C; Mg, Al - F HDL - F 2h40 ° C and Mg, Al - F HDL - F 24h40 ° C for each group, totaling 12 products. Precursors and products were characterized in structural, thermal and morphological form. The X-ray fluorescence spectrometry (EDX), X-ray diffraction (XRD), Fourier Transform Infrared Spectrometry (FTIR), fluorimetric electrophoresis potentiometry for quantification (HMDS), thermogravimetric analysis (TGA) and scanning electron microscopy. (SEM). The fluoride release kinetics of the products were performed at pH 5.5 and 7.0 over 21 days. The microbiological evaluation was followed by disc-diffusion methods in agar and microdilution in broth and agar using strains of S. mutans (ATCC 25175) at concentrations of 1000 and 200 μg/mL of the solutions tested. The structural evaluation confirmed the obtaining of fluoride products with a 3:1 molar ratio, crystalline, predominantly water and carbonate ions. Thermal analysis curves revealed more stable fluoride products compared to precursor HDLs. The micrographs revealed images of irregular, distorted and leafy clusters. In relation to the fluoride release, the acid medium generally implied higher ion release values and the predominant curves comprised logarithmic profiles and among the products, Mg, Al-F HDL-F 24h25 ° C of the group 3, with 46.6 (pH 5.5) and 45.7% (pH 7.0) at the end of the assay. Finally, the microbiological evaluation revealed inefficacy of the products against S. mutans at the concentrations tested. In view of the above, it was concluded that fluoridated HDLs were successful and they can be promising as a new nanoscale agent to be used in the control of dental caries. For this, assessments are required regarding the remineralizing potential and antimicrobial activity in other concentrations in order to better elucidate its action.