IN VITRO BIO-INTERACTIVITY OF MTA MIXED WITH DIFFERENT ACCELERANT SOLUTIONS

Aim: To evaluate and compare the biointeractivity (calcium and hydroxyl ion release into the leachate) of mineral trioxide aggregate (MTA) mixed with three different accelerant solutions.
Methods: MTA was mixed with 5% calcium chloride (Group CL), 15% disodium hydrogen orthophosphate (Group NaP), 0.1% citric acid (Group CA) or distilled water (Group DW) as control; each group comprised ten specimens (n=10). The specimens were prepared by packing the mixtures into plastic tubes, 1.5 mm in internal diameter and 10 mm in length. Each specimen was immersed in 10 ml deionized water. The calcium ion release and pH were measured in the leachate after 24, 72 and 168h of material immersion using an atomic absorption spectrophotometer and a digital pH-meter respectively. Data were analysed using 2-way analysis of variance (ANOVA) with repeated measures, 1-way ANOVA and Tukey post hoc test; p-values less than 0.05 indicated statistical significance (p<0.05).
Results: The accelerant type and time significantly influenced both calcium ion release and pH (p<0.001). Overall, Group CL showed the highest calcium ion release followed by Group CA (p<0.05 compared to each other and to Groups DW and NaP) then came Groups DW and NaP; there was no difference between the latter two groups (p>0.05). Group NaP showed the highest leachate pH compared to Group DW at all time points. In general, calcium ion release and pH decreased over the 168-hour duration.
Conclusions: Within the conditions of this study, it could be concluded that, among the used MTA accelerants, 5% calcium chloride solution could yield the highest calcium ion release, while 15% disodium hydrogen orthophosphate solution may have the highest alkalizing activity; such accelerants could provide MTA with enhanced biointeractive qualities besides accelerating its setting.