Comparative Evaluation of Mineral Trioxide Aggregate Obturation Using Four Different Techniques-A Laboratory Study

Abstract

This study aimed to compare the density of mineral trioxide aggregate (MTA) as a root canal filling material in the apical 5 mm of artificial root canals. Forty transparent acrylic blocks with 30-degree curved canals were instrumented and allocated into four compaction technique groups (n = 10): Lawaty (hand files); gutta-percha (GP) points; auger (nickel-titanium rotary files in reverse mode); and plugger technique. Filled canals were weighed after setting the MTA to calculate difference in mass. Two postoperative radiographs compared radiopacity by measuring luminance variations at 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm from the root apex. Obturation time was measured using a digital chronometer. The significance level was set to p < 0.05. The plugger group had a lower mass. Relative luminance was significantly higher for the Lawaty group than the plugger group at all examined apical levels. The relative luminance of the auger and GP groups were significantly higher than the plugger group at depths between 0.5 mm and 2 mm. Relative luminance was highest for the Lawaty technique at all depths between 0.5 mm and 4 mm. The Lawaty technique group was associated with increased obturation time compared with pluggers. Compacting MTA in curved canals with the Lawaty technique has the highest mass and radiopacity but requires more time.

Keywords: MTA; dental cements; dental materials; endodontics; root canal obturation; root canal therapy.

Figure 1

Experimental design: (a) acrylic block used with a custom-made composite resin crown; (b) acrylic block model after placement in the maxillary tooth mould of the phantom head; (c) MTA delivered to the canal using a hand file; (d) MTA placed into the canal using a rotary file (ProTaper Gold^® F2 not used in image); (e) MTA canal delivery using a GP point; and (f) MTA transferred to the canal using a plugger.

Figure 2

The Lawaty technique: hand files used to carry and pack MTA sequentially in a “step-back” method.

Figure 3

Comparison of the estimated mean values for relative luminance for each group at various depths from the apical end. Estimated differences in mean relative luminance compared to the plugger group generally decreased as the distance from the apex increased.

Figure 4

Representative radiographs from each group showing the apical 5 mm: (a) Lawaty group; (b) auger group; (c) GP group; and (d) the plugger group. Orange arrows indicate areas of reduced relative luminescence. The red arrow shows that the obturation is short of working length (also an area of reduced relative luminance).