Method: The setting time defined with a Gillmore needle represents the time elapsed from mixing to the time at which no indentation can be detected on the mixture surface. The initial setting time was determined corresponding to the ASTM C266-03 (2008) and ISO 9917 specifications. The initial setting was defined by using light needle 113.4g (d=2.13 mm, 0.3 MPa). Materials including iMTA® (Dentosolve), Dycal® (Caulk, Dentsply), Biodentine® (Septodont), and Proroot® MTA (Maillefere, Dentsply), were mixed according to manufacturer instructions. The iMTA is powder with calcia, silica, alumina, 3.5% nano-enriched soluble fluoride, silica fume, zirconium oxide, sulphate, and phosphate mixed with a hydration liquid. The iMTAs, including ultrafast version for cavity lining, have lower sulphate/aluminate ratio than the original MTA in order to decrease the setting time. Six specimens in each group were measured under controlled temperature and humidity: 37±1°C and 95±5% relative humidity. Data were submitted to one-way ANOVA with Bonferroni correction (STATA 13).
Result: The initial setting time (x̄ ± sd) of ultrafast iMTA (1m 31s ± 8s), all round iMTA mixed as clay (ie 6 drops, 6m 13s ±25s) or as cream (ie 7 drops, 7m 55s ±26s), and Dycal (3m 15s ± 13s) are significantly faster in comparison to Biodentine (38m 33s ± 2m 57s; p< 0.001) and ProRoot MTA (148m 40s ± 7m 47s; p< 0.001). The use of dental materials with long setting time in the crown may be a disadvantage due to the increased risks of dissolution and displacement.
Conclusion: iMTAs and Dycal have initial setting times which are significantly faster in comparison to ProRoot MTA and Biodentine.