ABSTRACT
Resumen: El mineral trióxido agregado (MTA) es un cemento usado principalmente para sellar perforaciones en órganos dentales debido a que endurece en presencia de humedad, está compuesto por cemento Portland y trióxido de bismuto. Objetivo: Analizar y comparar por medio de PIXE, DSC, TGA y DRX la composición química elemental y de fases del cemento MTA Angelus® y de un cemento Portland blanco (CPB-CA). Material y métodos: MTA Angelus® blanco y un cemento Portland blanco fueron analizados con PIXE en un acelerador de partículas; el análisis de fases cristalinas se realizó por medio de DRX y contrastado los picos con los de base de datos del ICDD, el DSC se realizó en un calorímetro hasta 900 °C. Resultados: PIXE detectó como elementos de mayor porcentaje fueron aluminio, silicio y calcio para ambos cementos; habiendo diferencias en los porcentajes de azufre; el bismuto sólo se detectó en MTA Angelus®. Se detectaron como elementos traza cobre y estroncio en el MTA Angelus®, además de zirconio en CPB-CA. La relación entre silicio-calcio y silicio-aluminio en los dos cementos es similar. Se identificaron tres fases cristalinas en ambos cementos, silicato dicálcico, silicato tricálcico y aluminato tricálcico; sin embargo, se identificó Bismita en el MTA Angelus® y sulfato de calcio en forma de yeso en CPB-CA, que se logró corroborar con la ayuda de la técnica DSC. Conclusiones: Se logró observar la baja cantidad de yeso en MTA Angelus® por medio de la calorimetría. Tanto las fases cristalinas como la composición química elemental son similares en ambos cementos.
Abstract: Mineral trioxide aggregate (MTA) is a cement mainly used to seal tooth perforations; this is due to the fact that it hardens when in presence of humidity. It is composed of Portland cement and Bismuth trioxide. Objective: To analyze and compare with PIXE, DSC, TGA and DRX elementary chemical and phase composition of MTA Angelus® cement with a white Portland cement (WPC). Material and methods: MTA Angelus® white and a white Portland cement were analyzed with PIXE in a particle accelerator, phase analyses were conducted with XRD contrasting peaks with those in the ICDD database. DSC was conducted in a calorimeter up to 900 oC. Results: PIXE detected the following as greater percentage elements: aluminum, silica and calcium for both cements. Differences were found with sulfur percentages; Bismuth was only detected in MTA Angelus®. Trace elements of copper and strontium were detected in MTA Angelus® and zirconium in WPC. Relationship between silica-calcium and silica-aluminum was similar in both cements. In both cements, three crystalline phases were detected: dicalcium silicate, tricalcium silicate and tricalcium aluminate. Nevertheless, Bismite was identified in MTA Angelus® and calcium sulfate in the form of gypsum in WPC, this was corroborated with DSC technique. Conclusions: In MTA Angelus®, low gypsum amounts were observed by means of calorimetry. In both cements, crystalline phases and elemental chemical composition were similar.
ABSTRACT
Maxillofacial prostheses is a dental medicine specialty aimed at restoring anatomical facial defects caused by cancer, trauma or congenital malformations through an artificial device, which is commonly attached to the skin with the help of an adhesive. The purpose of our research was to develop a pressure-sensitive adhesive (PSA) based on acrylic monomers, characterizing and determining its drying kinetics, that is to say the time it takes to lose 50 to 90% of its moisture. The adhesive synthesis was realized by means of emulsion polymerization; the composition of formulations was: (AA-MMA-EA) and (AA-MMA-2EHA) with different molar ratios. The formulation based on (AA-MMA-2EHA) with 50 w% of solids, presented good adhesive properties such as tack, bond strength, and short drying time. We propose this formulation as a PSA, because it offers an alternative for systemically compromised patients, by less irritation compared to organic solvent-based adhesives.
