The sealing ability of MTA apical plugs exposed to a phosphate-buffered saline

Objective: the aim of this study was to evaluate the influence of exposure of the mineral trioxide aggregate (mta) - with and without calcium chloride (cacl2) - to phosphate-buffered saline (pbs) on the apical microleakage using a glucose leakage system. material and methods: sixty root segments were randomly divided into 4 experimental groups (n=15). after resecting the apical segments and enlarging the canals with gates-glidden drills,the apical cavities were filled with mta with or without cacl2 and the root canals were dressed with a moistened cotton pellet or pbs,as follows: 1) mta/cotton pellet; 2) mta/pbs; 3) mta+10%cacl2/cotton pellet; 4) mta+10%cacl2/pbs. all root segments were introduced in floral foams moistened with pbs. after 2 months,all root segments were prepared to evaluate the glucose leakage along the apical plugs. the amount of glucose leakage was measured following an enzymatic reaction and quantified by a spectrophotometer. four roots were used as controls. the data were analyzed using kruskal-wallis and mann-whitney tests (p<0.05). results: there were no differences between groups 1 and 2 (p>0.05),and 3 and 4 (p>0.05). the addition of cacl2 to the mta significantly decreased its sealing ability (p<0.05). conclusion: the interaction with pbs did not improve the mta sealing ability. the addition of cacl2 to the mta negatively influenced the apical seal.