Micro-Computed Tomographic Evaluation of the Sealing Quality and Bond Strength of Different MTA Apical Plugs

Objective: This study aimed to compared the effects of different placement techniques to the sealing quality of mineral triokside aggregate (MTA) apical plugs at apexification technique by micro-computed tomography (micro-CT) and compared the bond strength to root dentin of an injectable MTA (BIOfactor MTA), MTA Angelus and AH Plus. Methods: Sixty dentinal root slices were obtained from 20 maxillary centrals.A canal-like hole was drilled into each slices canal space.The samples were divided into 3 groups (n=20).All materials were delivered into the holes. Push-out tests were performed and fracture types were analysed with a strereomicroscope. In the second part of the study,72 maxillary central teeth with standardised artificial divergent open apex were divided into 4 groups; MTA Angelus and BIOfactor MTA were mixed mechanically, and introduced to form 4 mm thick apical plugs by hand condensation or indirect-ultrasonic activation for 10 seconds. Incidence of external voids between dentin walls and MTA apical plugs and porosity inside MTA were determined by volumetric analysis with micro-CT. Results: No significantly difference was found between the bond strength values of the materials (p:0.370; p>0.05).The external voids and porous voids are similar in both MTA (p: 0.685; p>0.05).When indirect-ultrasonic activation was applied,there was significantly less porosity statistically than hand condensation (p:0.00; p<0.05). Conclusion: MTA Angelus and BIOfactor MTA materials showed similar results in terms of bond strength to root dentin, fracture types, adaptation to dentin walls and structural porosity rate. Both MTA materials showed less structural porosity when placed by indirect ultrasonic activation technique compared to manual condensation.