Abstract
BackgroundTo characterize the chemical composition and textural parameters of the MTA Repair HP precursor powder and their influence to hydration performance.Material and MethodsUn-hydrated precursor material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray fluorescence (XRF), laser diffraction (LD), N2 physisorption and field emission gun scanning electron microscopy (FEG-SEM). Setting time was assessed according to ASTM specification C 266. Hydrated material was analysed by XRD, FT-IR, energy dispersive X-ray (EDX) analysis and FEG-SEM.ResultsCa3SiO5 and Ca2SiO4, in addition to CaWO4 as radiopacifier are the main compositional phases. Other measured parameter indicates high specific surface area of 4.8 m2 g-1, high aluminium content of 1.7 wt.% and low initial and final setting times of 12 and 199 min, respectively. Singular microstructural features consisting of high aspect ratio nanoparticles are main constituents of un-hydrated precursor. Besides, FEM-SEM observation shows notably growth of hexagonal shaped plate-like morphologies homogeneously distributed along the sample during hydration process.ConclusionsThe short setting time measured for HP Repair, is correlated with high surface area of precursor powder, high Al content and the absence of compositional sulphate phases. Key words:Bioactive endodontic cements, hydration performance, MTA HP Repair, physicochemical parameters.
Highlights
Mineral Trioxide Aggregate (MTA) endodontic cement, is a versatile material indicated for clinical use as root-end filling material, perforation repair, vital pulp therapy or apical barrier formation in teeth with open apexes [1]
MTA main compositional formulation is based on calcium silicates in the form of tricalcium (Ca3SiO5) and dicalcium (Ca2SiO4) silicate
The setting times were measured from the start of mixing to the time at which no indentations could be seen on the surface of the specimen
Summary
Mineral Trioxide Aggregate (MTA) endodontic cement, is a versatile material indicated for clinical use as root-end filling material, perforation repair, vital pulp therapy or apical barrier formation in teeth with open apexes [1]. The powder ProRoot MTA contains bismuth oxide as radiopacifier, which plays a main role in cement hydration and in tooth discoloration [12]. The alteration of the composition of the material modifies its physical-chemical and functional properties, changing its biomechanical behaviour and its bioactive response In this context, a new material, MTA Repair HP (Angelus, Londrina, Brasil), with reported great plasticity and handling [11], in which the radiopacifier bismuth oxide has been replaced by calcium tungstate (CaWO4), has come onto the market. The chemical composition, textural properties and microstructure of the precursor ceramic powder of MTA Repair HP is characterised and analysed in relation with its hydration performance and setting time. Conclusions: The short setting time measured for HP Repair, is correlated with high surface area of precursor powder, high Al content and the absence of compositional sulphate phases
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