Introduction. Mineral trioxide aggregate (MTA) is one of the most commonly
used materials in endodontics. Given its shortcomings, there is an intensive
search for new materials. Calcium-silicate phase (CS phase) is a new material
synthesized by the method based on a combination of sol-gel process and
self-propagation synthesis which can significantly improve setting time
through accelerated hydration. The aim of this study was to explain the
mechanisms of hardening of CS phase in aqueous medium as similar mechanism is
expected in contact with body fluids. Materials and Methods. CS phases
Ca3SiO5 (C3S) and 2?-CaSiO4 (?-C2S) were synthesized from CaCl2?5H2O (Merck,
Germany). To investigate the process of hydration, CS were mixed with water
and kept at 37 ?C for 28 days in closed polyethylene containers. Analysis of
the composition of samples before and after immersion in water for 1, 3, 7
and 28 days was performed using X - ray diffractometry and IR. Results. XRD
patterns for hydrated samples during 1, 3, 7 and 28 days showed that the
amount of hydrated tobermorite phases relative to the amount of CS phase
changes with the time of hydration. After 1 day, in addition to the hydrated
phases, a significant amount of untransformed ?-C2S and C3S were found while
after 28 days hydrated CS phase was completely transformed to tobermorite
with a small amount of portlandite. Conclusion. Using combined method of
sol-gel and self-propagating waves at high temperature very active
nanostructured silicate phases were obtained. Hydration process of CS phases
was analyzed using XRD and FTIR, the mechanism of hydration was proposed and
it was pointed to the difficulties in determining the exact reaction as well
as the problem of determining the exact structure of tobermorite.
Wetting of liquid aluminum alloys on pure titanium at 873-973 K