Physicochemical properties and apatite precipitation behavior of experimental calcium silicate-based cements doped with phosphate compounds.

OBJECTIVES

This study aims to evaluate the solubility, pH, Ca release, setting time, and hydroxyapatite (HAp) formation of the tested materials.

METHODS

Four study groups were tested: NEX-MTA (NMTA; GC, Japan), NMTA with phosphorylated pullulan (MTA-PPL), NMTA with poly-PS (MTA-polyPS), and Biodentine (BD; Septodont, France). Solubility was measured after 7 and 28 days at 37 °C in deionized water. Ca release and pH evaluation were performed after immersion in deionized water at 3 h, 24 h, 7 days, and 28 days using pH and Ca meters. Setting times were determined with a Vicat apparatus, and apatite precipitation was evaluated through scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/ EDS) and Fourier transform infrared spectroscopy (FTIR) analysis 28 days in phosphate-buffered saline.

RESULTS

NMTA showed the lowest solubility; however, there was no statistically significant difference between NMTA and MTA-polyPS (P > 0.05). NMTA exhibited the most alkaline pH at all measured time points. Although MTA-polyPS consistently showed lower pH values than NMTA throughout the observation periods, no statistically significant differences were observed among MTA-polyPS, BD, and MTA-PPL at 28 days (P > 0.05). BD released the most Ca, with MTA-polyPS releasing the least. BD exhibited the shortest initial and final setting time (9.2 and 42 min, respectively), followed by MTA-polyPS, MTA-PPL, and NMTA. SEM/ EDS and FTIR indicated that MTA-polyPS had the highest apatite precipitation, with Ca/P ratios of 1.70 (NMTA) and 1.79 (MTA-polyPS). MTA-PPL and BD showed no significant apatite precipitation, with Ca/P ratios of 3.93 and 34.9, respectively.

SIGNIFICANCE

The incorporation of polyPS into calcium silicate-based cement may enhance apatite precipitation and accelerate the setting without altering the pH and solubility property.