Novel High-plasticity Repair Cements: Analysis of Physical Properties

Objectives: To evaluate the physical properties of novel high plasticity calcium silicate-based cements (MTA HP and MTA Flow). The association of zinc oxide (5% ZnO) in MTA Flow was also evaluated to inhibit dental discolouration.
Methods: Characterization was evaluated using SEM and EDS. Setting time was determined according to ISO 6876/2012. Dental discoloration analysis was evaluated in contact with bovine teeth. The colour was assessed after insertion, 24 hours and 28 days. Statistical analysis was performed using non-parametric Kruskal-Wallis/Dunn tests (p < 0.05).
Results: For initial setting time, the higher values were found for MTA (30.5 min), with statistical difference to all cements (p < 0.05). Contrary, the lower setting time was verified for MTA HP (4.61 min) (p > 0.05). For final setting time, the MTA also showed the high values (66.8 min) and MTA HP the lower (25 min) (p < 0.05). The addition of 5% ZnO into MTA Flow reduced initial and final setting time (p > 0.05). For discolouration, at 24 hours, the higher luminosity (L) was detected for MTA (89.6), with statistical difference for MTA Flow + 5% ZnO (84) (p < 0.05). The Delta E at 24 hours was higher for MTA (160.5) with statistical difference in relation to all the other cements (p < 0.05). At 28 days, the luminosity was similar to all the cements (p > 0.05), whilst the Delta E was higher for MTA (p < 0.05). The additon of 5% ZnO did not significantly altered the colour of MTA Flow in the periods evaluated (p > 0.05).
Conclusions: The MTA HP and MTA Flow presents different microstructure and lower setting time in comparison with MTA (p < 0.05). These cements have higher colour stability in relation to MTA at 24 hours and 28 days of contact with dental structures.