Evaluation of micro surface structure and chemical composition of two different calcium silicate–containing filling materials

Objective: To investigate and compare the composition and micro surface structure of two different calcium silicate–containing filling materials using energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM).
Methods: The materials investigated included DiaRoot BioAggregate (BA) and MTA Angelus (MTA-A). After mixing, each filling material was placed into cubes of 3 mm3. The hardening samples were compressed and broken and these samples were used for SEM examination. For elemental analysis and chemical composition, some samples were powdered and EDX was performed.
Results: EDX findings indicated that the major constituents of BA included calcium, oxygen, tantalum, and silicon. The chemical structure of MTA-A was similar to that of BA except for the absence of tantalum (radiopacifier). In addition, MTA-A contained some elements, e.g., aluminum, sodium, potassium, phosphorus, iron, rubidium, and strontium in trace amounts. The chemistry of compounds of BA filling material is more biologically compatible as a restorative material. In SEM images, BA was noted to be granular and almost spherical and particles of all sizes were observed. MTA-A was detected as a porous structure; its particles were granular, but locally planar layers were also detected.
Conclusion: The mineralogical composition of BA was different from that of MTA-A. As opposed to MTA-A, BA did not contain tricalcium aluminate phase and it included tantalum oxide as a radiopacifier. SEM images of MTA-A represented a more porous surface structure than that of BA. In light of these findings, BioAggregate seems to be a more suitable root-end filling material in terms of mineral content and surface structure.