Lakage study of MTA placed orthograde as an apical plug

Objectives: The purpose of the study was to compare the sealing ability of two types of mineral trioxide aggregate (MTA) when placed in the root canal with wide open apex as an apical plug by hand condensation or by hand condensation plus ultrasonic methods. Methods: Forty four freshly extracted single-rooted human teeth were used. The apex was prepared to a size of 1.30 mm after complete cleaning and shaping. The teeth were then randomly divided into four experimental groups. In group 1 and 2, gray MTA was placed by hand condensation or by hand condensation plus ultrasonic vibration in the apical 4 mm. In group 3 and 4, off-white MTA was placed by hand condensation or by hand condensation plus ultrasonic vibration in the apical 4 mm. After storing the prepared teeth at 100% humidity for 24 hours, the leakage of MTA plug was then evaluated by 1% methylene blue dye penetration method. Scanning electronic microscopy examination of the cross sections of the apical 4 mm was also performed. Results: There was no significant difference in preventing dye penetration between gray and off-white MTA placed by two different techniques. SEM examination indicated that the particle sizes and shapes of various components in the MTA are not homogeneous with bismuth particles significantly larger. The gap formation between these particles may have limited the ability of MTA to closely adapt to the canal walls. Conclusions: There was no significant differece between the gray MTA and off-white MTA placed by hand condensation or by hand condensation plus ultrasonic vibration in allowing the passage of methylene blue dye.