Discrepancies between the methods used for evaluation of Mineral Trioxide Aggregate’s handling characteristics

Objectives: To evaluate the extent of correlation between different tests methods used for evaluation of Mineral Trioxide Aggregate’s (MTA) handling characteristics by mixing it with distilled water (DW) and methylcellulose (MC).
Methods: A radiopaque calcium silicate cement (RCSC) was used as reference material and was mixed with three different liquid combinations; Group-1 (RCSC + DW), Group-2 (RCSC + 1% MC) and Group-3 (RCSC + 2% MC)(n = 6). The handling characteristics were evaluated using three different methods i.e. (1) flow test according to ISO: 6876, (2) flow test according to ADA specification no: 57 and (3) manual mixing and rating. The data collected was analyzed by one way analysis of variance (ANOVA) and a post hoc Tuckey’s test. The significance level was set at P < 0.05.
Results: Samples of Group-2 and 3 were observed to have improved consistency, cohesiveness and moldability. The flow of Group-2 and 3 (15.05 and 13.89 mm respectively) according to ISO flow test was significantly higher than group-1(10.73 mm) (P < 0.000) but, lower than the ISO specified minimum required flow of 20 mm. The results of flow test according to ADA showed all samples to have flow greater than the minimum required limit (ADA specified) with no statistical difference between the flow of Group-1 and 2 (P = 0.32). The handling characteristics of Group-1, 2 and 3 by manual mixing was rated as fair, good and excellent respectively.
Conclusions: Mixing RCSC with MC generally resulted in cement mixtures with improved consistency and greater flow. The results of three methods were different from each other and poorly correlated.