Phase formation, microstructure and setting time of MCM-48 mesoporous silica nanocomposites with hydroxyapatite for dental applications: Effect of the Ca/P ratio

Abstract

Nanocomposites of MCM-48 mesoporous silica and hydroxyapatite (HA) are investigated as possible alternatives for the commonly used Mineral Trioxide Aggregate (MTA) dental cement, and the effect of their Ca/P ratio on their structure, properties and setting times is reported. XRD, FTIR and EDS/SEM analysis of the nanocomposites indicate that crystalline HA is formed within the mesoporous silica structure. High Ca/P ratios lead to the formation of free CaO within the nanocomposite, decreasing its setting time; the shortest setting time (similar to 40 min), which occurs in the MCM-48/HA nanocomposite with a Ca/P ratio of 5, in physiological saline solution, is considerably shorter than the setting time of MTA (similar to 140 min under identical conditions). Thus, the shorter setting time of the MCM-48/HA nanocomposites, coupled with their lack of toxicity, high degree of bioactivity and their stability in tissue fluids, suggest that they could serve as a useful replacement for MTA.