Effect of Mineral Trioxide Aggregate Apical Plug Thickness on Fracture Resistance of Immature Teeth

The aim of this study was to compare the fracture resistance of simulated immature teeth after using different thicknesses of mineral trioxide aggregate (MTA) apical plugs. Fifty-two human maxillary anterior teeth were used. Five teeth were the positive control group; they were prepared using Peeso reamers to simulate immature teeth without any access cavity preparation. Access cavities of the 47 teeth were prepared, and the canals were instrumented with Peeso reamers. Five teeth served as the negative control; they were filled with calcium hydroxide. Forty-two teeth were divided into 3 groups; in groups 1, 2, and 3, MTA was placed into canals as a 3-mm and a 6-mm apical plug and a thorough canal length, respectively. The rest of the canals in groups 1 and 2 were filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). After the storage period, the roots were covered with a polyether impression material and were embedded into self-curing resin blocks. Each specimen was then subjected to fracture testing using a universal testing machine. Data were analyzed using 1-way analysis of variance with the Tukey post hoc test for multiple comparisons. The negative group showed the lowest fracture resistance compared with the other groups. The 3-mm apical plug group showed the highest fracture resistance (P .05). MTA should be used as an apical plug instead of root canal filling material to increase the fracture resistance of immature teeth. •Complete obturation of a root canal with mineral trioxide aggregate (MTA) may cause a tendency to fracture.•In contrast to the finding, no difference was found between 3- and 6-mm MTA apical plugs; both showed similar results.•MTA may be safely used for performing an apical barrier between 3- and 6-mm thicknesses in immature teeth.•An MTA apical plug could be placed into the root canal up to 6-mm thickness if required during the single-visit treatment of immature teeth without adversely affecting the resistance of tooth structures.