Micro-CT Evaluation of MTA Compaction Techniques in 3D-Printed Teeth With Simulated Perforating Internal Root Resorption: An in Vitro Study

Abstract

Background This study aimed to compare the effectiveness of manual compaction, indirect ultrasonic activation, and a novel sonic-activated endomotor in reducing voids during MTA placement in perforated internal root resorption cavities (IRR). Methods Thirty standardized 3D-printed resin teeth with simulated perforating IRR cavities (4 mm in diameter, located 4 mm from the apex, with a 2 mm buccal perforation) were fabricated. The samples were randomly divided into 3 groups: Manual compaction: MTA was placed and compacted using hand pluggers. Ultrasonic activation: MTA was placed and indirectly activated with an ultrasonic device at 30% power for 3 cycles of 10 s each. Sonic-activated endomotor: MTA was placed and compacted using the 812 MT endomotor. Specimens were stored at 37 degrees C in 100% humidity for 1-week. Micro-computed tomography (micro-CT) was used to evaluate the void volume. Intergroup comparisons were conducted using the Kruskal-Wallis test at a 5% significance level. Results The mean void volumes were 6.49 mm(3) in the manual compaction group, 2.61 mm(3) in the ultrasonic activation group, and 3.89 mm(3) in sonic-activated endomotor group. Although the manual compaction group exhibited the highest void volume, the differences among the groups were not statistically significant (P > 0.05). Conclusions Within the limitations of this in vitro study, all three MTA compaction techniques demonstrated comparable outcomes in the compaction of MTA in perforating IRR cavities. These findings suggest that, in such cases, the choice of technique may be guided by operator preference and clinical circumstances rather than expected differences in void reduction.