The Effect of Set Conditions on Volumetric Changes of Different Hydraulic Cements: An In Vitro Root-End Model

This study aimed to compare the percentage of volumetric changes between incompletely and completely set conditions of ProRoot MTA (MTA) and Endosequence Root Repair Material Fast-Set Putty (ERRM-FSP) as root-end filling materials in a simulated surgical environment.

Thirty-two human mandibular premolars with single, straight canals were selected. The canals were prepared and obturated with gutta-percha and AH-plus sealer. Retrograde cavities were created, and the teeth were divided into 4 groups (n = 8) based on materials and set conditions: (1) incompletely set MTA, (2) completely set MTA, (3) incompletely set ERRM-FSP and (4) completely set ERRM-FSP. After root-end filling, the incompletely set groups were immediately immersed in phosphate-buffered saline (PBS) while the completely set groups were stored in a humidity chamber for 7 days before immersion. The volume of root-end filling materials was assessed using micro-CT at 1- and 7-day post-immersion, and volumetric changes were compared using an independent t-test (P < 0.05).

MTA showed significantly greater volumetric changes in the incompletely set condition compared with the completely set condition at both time points (P < .05). Incompletely set MTA also had greater volumetric reductions than ERRM-FSP at the 7-day period (P = .004).

Incompletely set MTA exhibited significantly greater volumetric reduction compared to completely set MTA, whereas ERRM-FSP showed no significant difference between the two conditions.

These findings highlight differences in the volumetric stability of root-end filling materials under different set conditions, emphasising the need to test materials in conditions simulating clinical practice.