Micro-CT analysis of MTA apical plug placement: manual condensation, indirect ultrasonic activation, and sonic-activated rotary compaction techniques.

INTRODUCTION Mineral trioxide aggregate is widely used for apexification in immature permanent teeth owing to sealing ability and biocompatibility. However, placement in teeth with open apices may result in void, potentially compromising apical seal. This study compared MTA apical plug quality and procedural time among three placement techniques.

METHODS Thirty extracted human mandibular premolars with simulated open apices (apical diameter, 0.8 mm) were randomly assigned to three groups (n = 10). Four-millimeter MTA apical plugs were placed using manual condensation, indirect ultrasonic activation, or sonic-activated rotary compaction. Micro-computed tomography quantified closed porosity (internal voids) and open porosity (interfacial gaps) as percentages of total apical plug volume. Procedural time was recorded, and data were analyzed statistically.

RESULTS Sonic-activated rotary compaction produced lowest open porosity (0.001% ± 0.001%) and shortest procedural time (160.00 ± 6.50 s), but resulted in highest closed porosity (0.412% ± 0.076%). Manual condensation demonstrated highest open porosity (0.122% ± 0.063%) and moderate closed porosity (0.108% ± 0.076%), while indirect ultrasonic activation showed intermediate open porosity (0.006% ± 0.002%) and lowest closed porosity (0.079% ± 0.030%). Importantly, closed porosity did not differ significantly between manual and ultrasonic groups (P = .523). Indirect ultrasonic activation required longest procedural time (270.30 ± 7.27 s), followed by manual condensation (229.20 ± 6.34 s), whereas sonic-activated rotary compaction was the most time-efficient. All other intergroup differences were statistically significant (P < .001).

CONCLUSIONS Sonic-activated rotary compaction demonstrated lowest open porosity and greatest time efficiency among three techniques, although it produced highest closed porosity.