In vitro evaluation of the influence of ultrasonic activation on physicochemical properties of three endodontic repair materials

The influence of ultrasonic activation (UA) on the physicochemical properties of setting time (n = 5), volumetric stability (n = 10), alkalizing activity/calcium ions release (pH/Ca²⁺) (n = 10) and calcium/phosphate-rich substance formation in simulated body fluid (Hank's balanced salt solution; HBSS) of three cements was evaluated: white MTA-Angelus (MTA), MTA Repair HP (MTAHP) and Biodentine (BIO). It was observed that UA influenced the setting times (min) distinctly, delaying the initial setting time of MTA (40.8/64.6) and accelerating that of BIO (35.6/22.4). The final setting time of MTAHP (154.4/114.6) and BIO (64.4/42.4) were also accelerated (p < 0.05). Volumetric reduction was observed in all groups, with MTA/UA being the most volumetrically stable (0.98%); UA did not influence volumetric stability (p > 0.05). All groups exhibited an alkaline pH, with a disadvantage for MTAHP and MTAHP/UA at 24 h, 72 h and 168 h (p < 0.05). All groups showed Ca²⁺ release. The tested cements exhibited a favourable Ca/P ratio on their surface after 28 days.