Evaluation of pH and calcium ion diffusion from intracanal MTA and Bioaggregate to simulated external resorption cavities through dentinal tubules

Purpose: This in vitro study compared the effects of mineral trioxide aggregate (MTA), BioAggregate and calcium hydroxide on calcium and hydroxyl ion diffusion through dentinal tubules to the root surfaces without cementum in various root levels. 
Materials & Methods: The study consisted of 120 mature single-rooted mandibular premolar teeth. The teeth were decoronated and instrumented using Protaper Universal rotary files. To simulate external root resorption, artificial defects were created in cervical-middle-apical thirds of root surfaces. The teeth were divided into four main groups: Control (1), calcium hydroxide (2), MTA (3) and BioAggregate (4). In control group, root canals of specimens left empty. Other root canals of specimens filled with calcium hydroxide, MTA or BioAggregate. Each specimen was immersed in a vial containing 10 mL distilled water. Calcium concentrations and pH of the immersion media was measured at 1, 3, 7, 14, 21 and 28 days. Statistical analysis was accomplished by Kruskal–Wallis H and Mann–Whitney-U tests. 
Results: This study indicated that intracanal placement of both calcium hydroxide, MTA and BioAggregate resulted in the diffusion of calcium and hydroxyl ions across dentine. The results showed greater calcium and hydroxyl ions released by calcium hydroxide groups than MTA and BioAggregate groups (p0.05). 
Conclusion: MTA and BioAggregate may be preferable for external root resorption cases because of their stimulation of hard tissue formation and ion releasing ability.