ABSTRACT
Abstract Conventional orthodontic treatment with the use of stainless steel may be detrimental to oral health by promoting demineralizing lesions appearance and increasing adhesion and formation of bacterial biofilm, inducing the development of cavities. An alternative that has been researched to reduce the side effects of orthodontic treatment is the coating of materials with antimicrobial nanoparticles. Nanometric- sized particles increase their surface area and contact with the microbial membrane, consequently intensifying their bacteriostatic and bactericidal effect. In this work, hydrothermal synthesis, a "green" process was used to attach silver nanoparticles (AgNPs) to the surface of two different brands of orthodontic wires. The coated materials were analyzed for their physicochemical properties by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), which showed the distribution of AgNPs along the wires without modifying their properties. In the microbiological test, one of the brands showed a statistically significant difference in microbial adhesion and biofilm formation by Staphylococcus aureus and Streptococcus mutans. Results lead to the conclusion that antimicrobial orthodontic wires coated with silver nanoparticles through hydrothermal synthesis is a promising material for the improvement of orthodontic treatment.
Subject(s)
Orthodontic Wires , Staphylococcus aureus/drug effects , Streptococcus mutans/drug effects , Metal Nanoparticles , Anti-Bacterial Agents/pharmacology , Silver , Bacterial Adhesion , Calorimetry , Microscopy, Electron, Scanning , Dental PlaqueABSTRACT
ABSTRACT: The aim of the study was to evaluate the chemical composition and radiopacity of new calcium-silicatebased cements. Discs of 10 mm x 1 ± 0.1mm were prepared of BiodentineTM, TheraCal, Dycal and GC Fuji IX (n=5). The samples were radiographed directly on an PSP occlusal plate adjacent to an aluminium step wedge. The radiopacity of each specimen was determined according to ISO 9917/2007. Statistical analyses were carried out using ANOVA and Tukey's test at a significance level of 5 %. The chemical constitution of materials was determined by scanning electron microscopy (SEM) and energy dispersive x-ray element mapping. The radiopacities of the materials in decreasing order were: GC Fuji IX (3.45 ± 0.16 mm), Dycal (3.18 ± 0.17), BiodentineTM (2.79 ± 0.22), and TheraCal (2.17 ± 0.17). TheraCal showed the lowest radiopacity compared to the other materials, followed by BiodentineTM. Dycal and GC Fuji IX radiopacity values did not present significant statistical differences. Scanning electron microscopy and energy dispersive X-ray analysis revealed the presence of zirconium in BiodentineTM; and strontium, barium and zirconium in TheraCal as radiopacifying elements. The new calcium silicate cements present distinctive chemical composition. BiodentineTM contains zirconium as a radiopacifying element and has higher radiopacity values than TheraCal, which contains barium and strontium as radiopacifiers.
RESUMEN: El objetivo de este estudio fue evaluar la composición química y la radiopacidad de nuevos cementos en base a silicato de calcio. Discos de 10 mm x 1 ± 0,1 mm fueron preparados con BiodentineTM, TheraCal, Dycal y GC Fuji IX (n=5). Las muestras fueron radiografiadas directamente en una película PSP oclusal adyacente a una cuña escalonada de aluminio. La radiopacidad de cada espécimen fue determinada de acuerdo a la norma ISO 9917/ 2007. Se realizaron los análisis estadísticos con las pruebas ANOVA y test de Tukey con un nivel de significancia de 5 %. La constitución química de los materiales fue determinada con microscopía electrónica de barrido y con mapeo por análisis con dispersión de energía de rayos X. La radiopacidad de los materiales en orden decreciente fue: GC Fuji IX (3,45 ± 0,16 mm), Dycal (3,18 ± 0,7 mm), BiodentineTM (2,79 ± 0,22 mm), y TheraCal (2,17 ± 0,17 mm). TheraCal mostró la menor radiopacidad comparada con los otros materiales, seguido de BiodentineTM. Los valores de radiopacidad de Dycal y GC Fuji IX no presentaron diferencias estadísticas significativas. Los análisis de microscopía electrónica de barrido y mapeo por análisis con dispersión de energía de rayos X revelaron la presencia de zirconio en BiodentineTM; y de estroncio, bario y zirconio en TheraCal, como elementos radiopacos. Los nuevos cementos en base a silicato de calcio presentan una composición química distintiva. BiodentineTM contienen zirconio como elemento que provee radiopacidad y tiene mayor valor de radiopacidad que TheraCal, el cual contiene bario y estroncio como agente radiopaco.
Subject(s)
Humans , Silicate Cement/chemistry , Dental Materials/classification , Dental Materials/chemistry , Silicate Cement/analysis , Radiography, Dental , Silicates/chemistry , Calcium Compounds/chemistry , Physical PhenomenaABSTRACT
Abstract This study aimed to evaluate the cytotoxicity of a calcium aluminate cement (EndoBinder) containing different radiopacifiers, Bi2O3, ZnO or ZrO2, compared with Mineral Trioxide Aggregate (MTA). According to ISO 10993-12:2012 (E) recommendations, 0.2 g of each cement were applied in transwell inserts and placed in 24-well culture plates containing 1 mL of culture medium (DMEM). After 24 h of incubation, the extracts (DMEM containing components released from the cements) were applied to immortalized odontoblast-like MDPC-23 cells. Cell viability (MTT test), alkaline phosphatase activity (ALP), total protein production and cell morphology (Scanning Electron Microscopy - SEM) were evaluated. The volume of 50 µL of extract was used to determine the chemical elements released by the cements using Energy Dispersive Spectroscopy (EDS). The following groups were established (n=6): NC - negative control (without treatment); EB - EndoBinder without radiopacifier; EBBO - EndoBinder+Bi2O3; EBZnO - EndoBinder+ZnO; EBZrO - EndoBinder+ZrO2 and WMTA - White MTA. Data were subjected to statistical analysis (Kruskal-Wallis test, level of significance=5%). Cells exposed to the different versions of EndoBinder presented small reduction in viability, total protein production and ALP activity, with values similar to the NC and WMTA groups (p>0.05). Different elements (C, O, Na, Al, P, Si, Cl, Bi, K) released by the cements were detected in the extracts. However, the cells had no significant changes in their morphology. EndoBinder and MTA did not affect negatively the metabolism of the odontoblastic-like cells, showing it to be cytocompatible, irrespective of the used radiopacifier.
Resumo Este estudo avaliou a citotoxicidade de um cimento de aluminato de cálcio (EndoBinder) contendo diferentes radiopacificadores, Bi2O3, ZnO ou ZrO2, comparativamente ao trióxido mineral agregado (MTA). Seguindo a norma ISO 10993-12:2012 (E), 0,2 g de cada cimento foi aplicada em insertos transwell, que foram colocados em placas de cultura de 24 wells contendo 1 mL de meio de cultura (DMEM). Após 24 h de incubação, os extratos (DMEM contendo componentes liberados dos cimentos) foram aplicados sobre células pulpares imortalizadas MDPC-23. Viabilidade celular (teste de MTT), atividade da fosfatase alcalina (ALP), produção de proteína total e a morfologia das células (Microscópio Eletrônico de Varredura - MEV) foram avaliadas. Um volume de 50 µL do extrato foi utilizado para determinar, através de Espectroscopia de Energia Dispersiva (EDS), os elementos químicos liberados pelos cimentos. Os seguintes grupos foram estabelecidos (n=6): NC - controle negativo (sem tratamento); EB - EndoBinder sem radiopacificador; EBBO - EndoBinder+Bi2O3; EBZnO - EndoBinder+ZnO; EBZrO - EndoBinder+ZrO2 e WMTA - MTA branco. Os dados foram submetidos à análise estatística (teste de Kruskal-Wallis, nível de significância=5%). Células expostas às diferentes versões de EndoBinder apresentaram pequena redução na viabilidade, produção de proteína total e atividade da ALP, com valores semelhantes aos grupos NC e WMTA (p>0,05). Diversos elementos (C, O, Na, Al, P, Si, Cl, Bi, K) liberados pelos cimentos foram detectados nos extratos. Entretanto, as células não apresentaram alterações significativas em sua morfologia. EndoBinder e MTA, não afetaram negativamente o metabolismo das células odontoblastóides, mostrando-se citocompatíveis, independente do radiopacificador utilizado.