Impact of the addition of calcium hydroxide on the physico-chemical and mechanical properties of cement containing calcium silicate and salicylate resin

Aims:  The aim of this study was to evaluate pH, calcium ion release, solubility, and push-out bond strength of Biodentine (BD), Bioaggregate (BA), MTA salicylate experimental sealer containing 10% (MTAE 10-CH) or 20% calcium hydroxide (MTAE 20-CH) and White MTA Angelus (MTA). Materials and Methods: Fifty acrylic teeth with root-end filling materials (n = 10) were immersed in ultrapure water to measure pH and calcium ion release, at 7 and 30 days. In the solubility test the same kind of samples were scanned by Micro-CT before and after immersion in ultrapure water for 7 and 30 days. Fifty slices of conoid bovine tooth were obtained from the apical third of the root and retrofilled (n = 10). After 7 days the specimens were submitted to push-out bond strength test. Results: The BD and BA presented the highest alkaline values at 7 days. At 30 days, MTAE10-CH presented the highest alkaline values. The MTA presented the highest calcium ion release in the two periods evaluated. The BA and MTA presented the lowest solubility values. At 30 days, these values were higher at 3% of solubility, in relation to other groups. BD presented the highest and MTAE 10-CH the lowest bond strength. Bioaggregate and white MTA presented the lowest solubility and similar chemical properties. Although Biodentine presented the highest bond strength value, it showed high solubility. Conclusion: Bioaggregate and white MTA presented the lowest solubility and similar chemical properties. Biodentine showed satisfactory bond strength to apical dentine but exhibited high solubility. Experimental MTA sealers with 10% or 20% calcium hydroxide showed high solubility and poor bond strength.