A Microstructure Insight of MTA Repair HP of Rapid Setting Capacity and Bioactive Response

Abstract

Mineral trioxide aggregate (MTA) is considered a bioactive endodontic material, which promotes natural mineralization at the material-tooth tissue interface. MTA Repair HP stands out because of the short setting time and the quick and effective bioactive response in vitro. The bioactivity, depens on material composition and microstructure. This work is devoted to analyze MTA Repair HP microstructural features, of both the powder precursor and set material, to get insights into the material physicochemical parameters—functionality performance relationships. Transmission electron microscopy (TEM), and field emission gun scanning electron microscopy (FEG-SEM) coupled with energy-dispersive X-ray (EDX) analyses were performed. X-ray diffraction (XRD) measurements were carried out at different times to investigate setting process. Bioactivity evaluation in vitro was carried out by soaking the processed cement disk in simulated body fluid (SBF). The presented results point out those MTA Repair HP precursor material characteristics of tricalcium silicate particles of nanometric size and high aspect ratio, which provide an elevated surface area and maximized components dispersion of calcium silicate and very reactive calcium aluminate. The MTA Repair HP precursor powder nanostructure and formulation, allows a hydration process comprising silicate hydrate structures, which are very effective to achieve both fast setting and efficient bioactive response.

Major Changes in the Development of Calcium Silicate-Based Cements in Dentistry

“…The nanometric size automatically increases the active surface for hydration, optimizes the setting time (12 min initial setting time), and favors the formation of nanoporous calcium aluminate silicate hydrate microstructure. [10] The radiopacifier incorporated in this material is calcium tungstate.…”

New Bioactive Calcium Silicate Cement Mineral Trioxide Aggregate Repair High Plasticity (MTA HP)—A Systematic Review

“…A total of 16 papers were included into the group discussing the physicochemical parameters of MTA HP [ 5 , 16 , 17 , 23 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. The analysed selected physicochemical parameters of MTA HP, together with the most important results are given in Table 6 .…”

“…The group of research papers on the biological properties comprised a total of 18 scientific articles, including: seven studies on human cells in vitro [ 12 , 23 , 24 , 25 , 26 , 27 , 28 ], seven on Wistar rats in vivo [ 6 , 9 , 18 , 19 , 20 , 21 , 22 ], two research papers on mice in vitro [ 21 , 29 ] and three papers cells in vitro [ 37 , 38 , 39 ]. A brief description of the aforementioned studies is presented in Table 7 .…”

“…Jiménez-Sánchez et al (2020) found that the structure of the MTA HP tricalcium silicate particles ensures a very close contact between the calcium silicate and calcium aluminate and thus favors the hydration reaction. In this way, hydrated calcium aluminate silicate is formed which is responsible for the biocompatibility and speed of the reaction [ 38 ]. El Reash et al (2019) found that MTA HP was less alkaline (pH = 11.5) compared to iRoot BP Plus (pH 12.1) [ 27 ].…”

Sol–Gel Synthesis of Endodontic Cements: Post-Synthesis Treatment to Improve Setting Performance and Bioactivity

“…Specifically in relation to endodontic cements, dicalcium and tricalcium silicates are the main components [ 3 , 19 ], and can be successfully improved in terms of textural properties by sol–gel synthesis [ 20 , 21 ]. However, the selection of the different synthesis variables, such as the type of reagents, their molar ratios, the sequence of incorporation and reaction times etc., is critical to control these material properties and requires further study.…”