mineral trioxide aggregate ( mta ) was developed to be used in endodontic complications , 
 as well as in apical surgery . actually , it is also recommended to be 
 used in pulp conservative treatments and in obturation of the apical portion of immature 
 teeth .
mta induces a new apical cementum deposition when used in root canals . however , its handling is difficult for 
 use in root canal obturations . 

several calcium silicate - based sealers were developed to be used as a root canal filling 
 material , such as endo - cpm - sealer ( egeo , temperley , buenos aires , argentina ) , proroot 
 endo sealer ( dentsply maillefer , ballaigues , switzerland ) and an experimental cement , 
 mtas .
recently , a new formulation of mta - based cement ( mta fillapex ; 
 angelus indstria de produtos odontolgicos s.a . , londrina , paran , brazil ) was created 
 to be used as a root canal sealer . 

the composition of mta fillapex after mixing is mta , salicilate resin , natural resin , 
 bismuth and silica , according to the manufacturer .
mta fillapex has an antibacterial effect against e. faecalis before 
 setting and adequate biocompatibility . despite these 
 biological properties ,
mta fillapex 
 had the lowest push - out values to root dentine compared with ah plus and iroot sp 
 sealers .
but in another study , 
 mta fillapex presented acceptable resistance to dislodgement , which was similar to ah 
 plus .
a possible reason for 
 this different result can be attributed to the difficulty in handling due to excessive 
 flowability .
excessive flowability can favor apical 
 extrusion and injure the periapical tissue , mainly in teeth with a wide foraminal 
 opening . a suggestion 
 in order to decrease the flowability is the addition of calcium hydroxide into the 
 sealer . on the other hand
, the ideal endodontic sealer should be biocompatible and able to 
 induce mineralized tissue formation .
these properties are directly associated with the 
 alkalization potential and calcium release of the materials .
calcium hydroxide provides an alkaline ph and calcium 
 ion release , leading to biochemical effects that culminate in the acceleration of the 
 repair process .
the mta fillapex 
 sealer ( angelus ) has an alkaline ph and promotes calcium release .
however , the effects of the addition of 
 calcium hydroxide into mta fillapex with the objective of reducing sealer flowability 
 are unknown .
the aim of this study was to evaluate the flowability , ph level and calcium ion release 
 of mta fillapex , with the addition of 5% or 10% calcium hydroxide powder ( in weight ) , 
 compared to pure mta fillapex and ah plus .
the sealers used in this study were : ah plus ( dentsply detrey , konstanz , germany ) and 
 the mta fillapex ( mtaf ) ( angelus indstria de produtos odontolgicos s.a . , londrina , 
 paran , brazil ) .
the mtaf was used pure or with the addition of 5% ( mtaf5 ) or 10% 
 ( mtaf10 ) calcium hydroxide ( labsynth , diadema , so paulo , brazil ) , in weight . for the 
 ah plus
, the base and catalyst pastes were used in equal parts , in the proportion of 
 1:1 ( w / w ) .
the root canal sealers were mixed according to conditions recommended by the 
 manufacturer and the flowability test was performed according to the iso 6876:2001 
 requirements .
forty polyethylene tubes measuring 10 cm in length and 1.5 mm in internal diameter 
 were filled with the sealers to be evaluated . for the ph level and calcium ion 
 release evaluation ,
10 samples were prepared from each material studied . immediately 
 after manipulating the materials ,
the tubes were filled and weighed to check the 
 standardization of the amount of sealer in each tube ( 0.002 g ) and placed in 
 polypropylene flasks ( injeplast , so paulo , so paulo , brazil ) containing 10 ml of 
 deionized water . the tubes were kept at 37c ( fanem , so paulo , so paulo , brazil ) 
 during the entire study .
after 24 h , 7 and 14 days , the water was assessed for ph 
 levels and calcium release .
previous to the immersion of the specimens , the ph level 
 and calcium ion concentration of the deionized water were verified , attesting a ph 
 level of 6.8 and a total absence of calcium ions .
the tubes containing the sealers 
 were placed in new flasks with 10 ml of deionized water for further analyses in the 
 different time periods .
measurements were performed with a ph meter q400as ( quimis , diadema , so paulo , 
 brazil ) in constant temperature ( 25c ) .
after 24 h of immersion , the tubes were 
 carefully removed and placed into another flask with an equal amount of new deionized 
 water .
this procedure was repeated for a total of 336 h with the solution changed at 
 24 h , 7 and 14 days .
the ph values were compared by the anova and tukey tests , at a 
 5% significance level .
the calcium release was measured using an aa7000 atomic absorption spectrophotometer 
 ( shimadzu , nakaygio - ku , kyoto , japan ) , in accordance to the manufacturer 's 
 instructions . for the reading ,
6 ml of the standard solutions or water samples were 
 associated with 2 ml of lanthanum nitrate solution .
for the white solution , 6 ml of 
 deionized water was associated with the same amount of lanthanum nitrate solution . 
 with the standard solutions ,
the white solutions and the prepared sample , the reading 
 was carried out using an atomic absorption spectrophotometer .
the calcium release was calculated 
 by the equation of the line of the standard curve .
the reading of the calcium release 
 was taken in the same periods used for measuring the ph level .
the calcium release 
 values were compared by the anova and tukey tests , at a 5% significance level .
the sealers used in this study were : ah plus ( dentsply detrey , konstanz , germany ) and 
 the mta fillapex ( mtaf ) ( angelus indstria de produtos odontolgicos s.a . , londrina , 
 paran , brazil ) .
the mtaf was used pure or with the addition of 5% ( mtaf5 ) or 10% 
 ( mtaf10 ) calcium hydroxide ( labsynth , diadema , so paulo , brazil ) , in weight . for the 
 ah plus
, the base and catalyst pastes were used in equal parts , in the proportion of 
 1:1 ( w / w ) .
the root canal sealers were mixed according to conditions recommended by the 
 manufacturer and the flowability test was performed according to the iso 6876:2001 
 requirements .
forty polyethylene tubes measuring 10 cm in length and 1.5 mm in internal diameter 
 were filled with the sealers to be evaluated . for the ph level and calcium ion 
 release evaluation ,
10 samples were prepared from each material studied . immediately 
 after manipulating the materials ,
the tubes were filled and weighed to check the 
 standardization of the amount of sealer in each tube ( 0.002 g ) and placed in 
 polypropylene flasks ( injeplast , so paulo , so paulo , brazil ) containing 10 ml of 
 deionized water . the tubes were kept at 37c ( fanem , so paulo , so paulo , brazil ) 
 during the entire study .
after 24 h , 7 and 14 days , the water was assessed for ph 
 levels and calcium release .
previous to the immersion of the specimens , the ph level 
 and calcium ion concentration of the deionized water were verified , attesting a ph 
 level of 6.8 and a total absence of calcium ions .
the tubes containing the sealers 
 were placed in new flasks with 10 ml of deionized water for further analyses in the 
 different time periods .
measurements were performed with a ph meter q400as ( quimis , diadema , so paulo , 
 brazil ) in constant temperature ( 25c ) . after 24 h of immersion , the tubes were 
 carefully removed and placed into another flask with an equal amount of new deionized 
 water .
this procedure was repeated for a total of 336 h with the solution changed at 
 24 h , 7 and 14 days .
the ph values were compared by the anova and tukey tests , at a 
 5% significance level .
the calcium release was measured using an aa7000 atomic absorption spectrophotometer 
 ( shimadzu , nakaygio - ku , kyoto , japan ) , in accordance to the manufacturer 's 
 instructions . for the reading ,
6 ml of the standard solutions or water samples were 
 associated with 2 ml of lanthanum nitrate solution .
for the white solution , 6 ml of 
 deionized water was associated with the same amount of lanthanum nitrate solution . 
 with the standard solutions , the white solutions and the prepared sample ,
the calcium release was calculated 
 by the equation of the line of the standard curve .
the reading of the calcium release 
 was taken in the same periods used for measuring the ph level .
the calcium release 
 values were compared by the anova and tukey tests , at a 5% significance level .
the representative mean and standard deviation for flowability values from each sealer 
 are presented in figure 1 ( in mm ) .
mtaf showed 
 higher flowability ( 29.4 mm ) than the other sealers ( p<0.05 ) .
the flowability of the 
 mtaf5 was lower than the mtaf and ah plus ( p>0.05 ) ; however , it was in accordance 
 with the iso 6876:2001 requirements .
different letters indicate 
 statistically significant differences ( p<0.05 ) the mtaf10 showed the lowest flowability in relation to the other sealers ( p<0.05 ) 
 and this value was below the iso 6876:2001 requirements ( p<0.05 ) .
the flowability 
 means and standard deviations ( in mm ) for the mtaf , mtaf5 , mtaf10 and ah plus were 29.40 
 ( 1.05 ) , 20.75 ( 0.89 ) , 16.80 ( 0.71 ) and 21.91 ( 0.36 ) , respectively .
the representative mean and standard deviation of ph values and calcium release from 
 each sealer in different periods are presented in figures 
 2 and 3 , respectively . for all periods , 

the ah plus showed the lowest ph value ( p<0.05 ) . at 24 h ,
the mtaf , mtaf5 and mtaf10 
 showed similar ph values ( p>0.05 ) . at 7 and 14 days ,
the mtaf5 and mtaf10 showed 
 similar ph values ( p<0.05 ) and higher ph level than the mtaf ( p<0.05 ) .
different 
 letters indicate statistically significant differences ( p<0.05 ) for all periods , the ah plus showed the lowest means of calcium release ( p<0.05 ) .
on 
 the other hand , the mtaf5 and mtaf10 showed similar calcium release ( p>0.05 ) and 
 lower calcium release than the mtaf .
calcium release ( mg / l ) from each sealer studied in the different experimental 
 periods .
different letters indicate statistically significant differences 
 ( p<0.05 ) for all periods , the ah plus showed the lowest means of calcium release ( p<0.05 ) .
on 
 the other hand , the mtaf5 and mtaf10 showed similar calcium release ( p>0.05 ) and 
 lower calcium release than the mtaf .
the addition of 5% calcium hydroxide to the mtaf provided a reduction of the 
 flowability , in accordance with iso requirements .
its ph level was alkaline in all 
 periods but the calcium release was lower than pure mta fillapex . despite the addition 
 of 10% calcium hydroxide to mta fillapex
, it provided a reduction in flowability , and 
 this mixture is in disagreement with the iso 6876:2001 requirements .
the flowability test results revealed that the addition of calcium hydroxide provides a 
 reduction in flowability of the mtaf .
this can be explained by an increase in the 
 powder / liquid ratio also promoted , in accordance with that observed in a previous 
 study .
except for the mtaf10 , 
 all sealers were in accordance with the iso 6876:2001 requirements .
it has been suggested that in order to stimulate mineralization , a material should have 
 an alkaline ph level and calcium release .
the methodologies used for the ph level and calcium release 
 evaluations were similar to other studies .
the mtaf5 and mtaf10 
 presented ph levels similar to the mtaf , but only in a 24 h period . after this time , the 
 ph values were higher than any other sealer .
for all periods , the mtaf showed a higher calcium release despite the fact that calcium 
 hydroxide was added in the mtaf5 and mtaf10 .
( 2004 ) observed that the addition of 10% calcium 
 hydroxide in some sealers causes variations in setting time .
therefore , the addition of 
 calcium hydroxide in the mtaf could also have reduced the setting time of the sealer and 
 consequently its solubility , consequently reducing the calcium release .
in contrast with 
 this result , the addition of calcium hydroxide did not alter the ah plus setting 
 time .
however , the compositions 
 of these sealers are different . ah plus sealer presented lower calcium release than the 
 other sealers , although it contains tungstate calcium in its composition .
these results 
 are consistent with other studies also carried out with atomic absorption 
 spectrophotometry . through a comparative analysis of the compositions described by the manufacturers , it 
 was observed that the mtaf and sealapex ( sybronendo , orange , california , usa ) contain 
 several similar substances in their formulations .
thus , it is possible that many 
 reactions and effects described in the sealapex also occur with the mtaf .
( 2007 ) report that a 
 possible reason for the high calcium release provided by the sealapex is related with 
 the presence of 24% calcium hydroxide . since the sealer has a porous matrix with a low 
 dimensional stability and high water absorption , the calcium is easily 
 released . on the other hand ,
the addition of substances with calcium in the mta promotes a 
 reduction of the setting time .
thus , 
 the addition of calcium hydroxide in the mtaf could have interfered in the setting time 
 and consequently in the calcium release .
this could be a possible reason for the higher 
 calcium release presented by mtaf when compared to the mtaf5 and mtaf10 .
its use as an 
 endodontic sealer requires further adjustments , since its handling is very difficult . 

mtaf is a new calcium silicate - based sealer whose flowability is in accordance with the 
 iso 6876:2001 requirements ; 
 clinically , however , it is very high , which can favor the extrusion of the material to 
 the apical tissues .
the purpose of adding 5% calcium hydroxide ( in weight ) to the total 
 weight of the sealer is to obtain an adequate alternative .
based on the methods and conditions employed in the present study , it is concluded that 
 the addition of 5% calcium hydroxide ( in weight ) to the mtaf provides a reduction in the 
 flowability of the sealer , in conditions required by the iso 6876:2001 specifications 
 and favors a higher alkaline ph .
 recently , various calcium silicate - based sealers have been introduced for use in root 
 canal filling . 
 the mta fillapex is one of these sealers , but some of its 
 physicochemical properties are not in accordance with the iso requirements.objectivethe aim of this study was to evaluate the flowability , ph level and calcium 
 release of pure mta fillapex ( mtaf ) or containing 5% ( mtaf5 ) or 10% ( mtaf10 ) 
 calcium hydroxide ( ch ) , in weight , in comparison with ah plus sealer.material and methodsthe flowability test was performed according to the iso 6876:2001 requirements . 
 for the ph level and calcium ion release analyses , the sealers were placed 
 individually ( n=10 ) in plastic tubes and immersed in deionized water . 
 after 24 
 hours , 7 and 14 days , the water in which each specimen had been immersed was 
 evaluated to determine the ph level changes and calcium released . 
 flowability , ph 
 level and calcium release data were analyzed statistically by the anova test 
 ( =5%).resultsin relation to flowability : mtaf > ah plus > mtaf5>mtaf10 . in relation to the 
 ph level , for 24 h : mtaf5=mtaf10=mtaf > ah plus ; for 7 and 14 days : 
 mtaf5=mtaf10>mtaf > ah plus . 
 for the calcium release , for all periods : 
 mtaf > mtaf5=mtaf10>ah plus.conclusionsthe addition of 5% ch to the mta fillapex ( in weight ) is an alternative to reduce 
 the high flowability presented by the sealer , without interfering in its 
 alkalization potential . 