Estudio experimental sobre los posibles efectos citotóxicos y genotóxicos in vitro del hidróxido de calcio

72 páginasEl hidróxido de calcio es una material que ha sido empleado en la endodoncia por tener una excelente actividad antimicrobiana y un efecto curativo de la pulpa. Por esta razón existen diferentes presentaciones de este material de acuerdo a la aplicación específica y al efecto deseado. Para la validación de cualquier material se deben desarrollar pruebas in vitro, cuyo resultado demuestre de una forma aproximada los posibles efectos del material. Los ensayos cometa y con MTT son pruebas que permiten determinar de manera precisa y económica la genotoxicidad y la citotoxicidad respectivamente, valiéndose de cultivos celulares expuestos a un agente a evaluar. De manera más específica el ensayo cometa identifica los daños de la cadena sencilla y doble del DNA, mientras que el ensayo con MTT evalúa el metabolismo y la actividad enzimática de la célula viva. En el presente trabajo se evaluó el potencial efecto citotóxico y genotóxico del hidróxido de calcio producido por la compañía New Stetic, comparado con los producidos por las empresas Kerr (Life®) y Dentsply (Dycal®), las cuales son marcas ampliamente reconocidas y estudiadas en el campo endodóntico. Para lo cual se estandarizaron los protocolos de los ensayos con MTT y Cometa. Se realizó una revisión sobre las metodologías utilizadas para la evaluación de la biocompatibilidad de materiales utilizados en odontología, con énfasis en el hidróxido de calcio, adoptando las sugerencias de la literatura internacional, con el fin de cumplir los objetivos propuestos. Se encontró que el hidróxido de calcio producido por New Stetic, presenta un menor efecto citotóxico y un efecto genotóxico mayor que las demás marcas evaluadas, pero no lo suficiente como para considerar que este material es altamente genotóxico.ABSTRACT: Calcium hydroxide is a material that has been employed in the endodontic field, due to its excellent antimicrobial activity and its healing effect in dental pulp. For the above given reason, there are a whole lot of different types of calcium hydroxide according to the specific application and the desired effect. In order to validate any material, it is necessary to develop in vitro tests which allow to obtain accurate results showing the possible effects of the material. The comet assay and the MTT reduction are tests that allow to determine in a precise and economic way, the genotoxicity and cytotoxicity respectively, using cell cultures in direct contact with the evaluated agent. This study evaluates the potential cytotoxic and genotoxic effects of calcium hydroxide manufacturated by New Stetic Inc. using as references well-recognized products such as Life® and Dycal®. For this reason the comet assay and MTT reduction test were used, as tools, after their standardization in the laboratory. At first, the type of calcium hydroxide was recognized according to the applications suggested by the manufacturers, so then, analyzes it with direct contact assay. It was found that calcium hydroxide manufactured by New Stetic Inc. showed a less cytotoxic effect than the other two products, and a higher genotoxic effect than the others, but not higher enough to consider it capable of damaging acutely DNA strands.PregradoIngeniero(a) Biomédico(a

Síntesis y caracterización de hidrogeles de alcohol polivinílico por la técnica de congelamiento/descongelamiento para aplicaciones médicas.

Usando diferentes ciclos de congelamiento/descongelamiento se prepararon hidrogeles de alcohol polivinílico semicristalino 7,5 % y 12 % en concentración. La cinética y el grado de hinchamiento, los estados del agua y la resistencia a la tracción se evaluaron por gravimetría, calorimetría diferencial de barrido (DSC) y pruebas de tracción, respectivamente. Los resultados indican que los hidrogeles de menor concentración y con menor número de ciclos presentan cinética y grado de hinchamiento mejores y menor resistencia a la tracción. Las DSC permitieron determinar la presencia de agua libre y de agua vinculada congelable. Las características de estos hidrogeles permiten clasificarlos para diferentes aplicaciones médicas.Usando diferentes ciclos de congelamento/descongelamento se prepararam hidrogéis de álcool polivinílico semicristalino 7,5 % e 12 % em concentração. A cinética e o grau de inchamento, os estados da água e a resistência à tração se avaliaram por gravimetria, calorimetria diferencial de varrido (DSC) e provas de tração, respectivamente. Os resultados indicam que os hidrogeis de menor concentração e com menor número de ciclos apresentam cinética e grau de inchamento melhores e menor resistência à tração. As DSC permitiram determinar a presença de água livre e de agua ligada congelável. As características destes hidrogeis permitem classificá-los para diferentes aplicações médicas.Using different cycles of freeze-thawing, semicrystalline polyvinyl alcohol hydrogels were synthesized in concentrations of 7.5 % and 12 %. The kinetic and grade of swelling, states of water and the tensile strength were calculated by gravimetry, by differential scanning calorimetry, DSC, and the tensile tests respectively. The results show that hydrogels with less concentration and cycles have better grade and kinetic of swelling, while the tensile strength is lower. The DSC results allow us to determine the free and freezable bound waters in our hydrogels. The characteristics obtained from these hydrogels lead their classification for different medical applications

Release Behavior and Antibacterial Activity of Chitosan/Alginate Blends with Aloe vera and Silver Nanoparticles

Aloe vera is a perennial plant employed for medical, pharmaceutical and cosmetic purposes that is rich in amino acids, enzymes, vitamins and polysaccharides, which are responsible for its therapeutic properties. Incorporating these properties into a biopolymer film obtained from alginate and chitosan allowed the development of a novel wound dressing with antibacterial capacity and healing effects to integrate the antibacterial capacity of silver nanoparticles with the healing and emollient properties of Aloe vera gel. Three alginate-chitosan matrices were obtained through blending methods using different proportions of alginate, chitosan, the Aloe vera (AV) gel and silver nanoparticles (AgNps), which were incorporated into the polymeric system through immersion methods. Physical, chemical and antibacterial characteristics were evaluated in each matrix. Interaction between alginate and chitosan was identified using the Fourier transform infrared spectroscopy technique (FTIR), porosity was studied using scanning electron microscopy (SEM), swelling degree was calculated by difference in weight, Aloe vera gel release capacity was estimated by applying a drug model (Peppas) and finally antibacterial capacity was evaluated against S. Aureus and P. aeruginosa. Results show that alginate-chitosan (A (1:3 Chit 1/Alg 1); B (1:3 Chit 1.5/Alg 1) and C (3:1 Chit 1/Alg 1/B12)) matrices with Aloe vera (AV) gel and silver nanoparticles (AgNps) described here displayed antibacterial properties and absorption and Aloe vera release capacity making it a potential wound dressing for minor injuries

Synthesis and characterization of polyvinyl alcohol hydrogels by freezing/thawing technique for medical applications

Usando diferentes ciclos de congelamiento/descongelamiento se prepararon hidrogeles de alcohol polivinílico semicristalino 7,5 % y 12 % en concentración. La cinética y el grado de hinchamiento, los estados del agua y la resistencia a la tracción se evaluaron por gravimetría, calorimetría diferencial de barrido (DSC) y pruebas de tracción, respectivamente. Los resultados indican que los hidrogeles de menor concentración y con menor número de ciclos presentan cinética y grado de hinchamiento mejores y menor resistencia a la tracción. Las DSC permitieron determinar la presencia de agua libre y de agua vinculada congelable. Las características de estos hidrogeles permiten clasificarlos para diferentes aplicaciones médicas.Using different cycles of freeze-thawing, semicrystalline polyvinyl alcohol hydrogels were synthesized in concentrations of 7.5 % and 12 %. The kinetic and grade of swelling, states of water and the tensile strength were calculated by gravimetry, by differential scanning calorimetry, DSC, and the tensile tests respectively. The results show that hydrogels with less concentration and cycles have better grade and kinetic of swelling, while the tensile strength is lower. The DSC results allow us to determine the free and freezable bound waters in our hydrogels. The characteristics obtained from these hydrogels lead their classification for different medical applications