Setting time and expansion in different soaking media of experimental accelerated calcium-silicate cements and ProRoot MTA.
OBJECTIVE
The setting time and the expansion in deionized water, phosphate-buffered saline (PBS), 20% fetal bovine serum (FBS)/80% PBS or hexadecane oil of experimental accelerated calcium-silicate cements and ProRoot MTA were evaluated.


METHODS
Different compounds such as sodium fluoride, strontium chloride, hydroxyapatite, and tricalcium phosphate were separately added to a basic experimental calcium-silicate cement to test their effect on setting and expansion. The initial and final setting times were determined using appropriate Gilmore needles. A linear variable differential transformer (LVDT) device was used to test the restricted hygroscopic linear expansion over 180 minutes of cements immersed in different solutions. Results were statistically compared using a 2-way ANOVA test (cement type versus solution type).


RESULTS
All experimental cements showed initial setting times between 28 and 45 minutes and final setting times between 52 and 80 minutes. MTA showed a final setting time of 170 minutes. Final setting time of all experimental cements was faster than MTA. All cements showed slight (0.04%-0.77%) expansion in water, PBS, or FBS/PBS. Only fluoride-containing cement showed a significant expansion in water (6.68%) and in PBS (6.72%). The PBS/FBS contamination significantly reduced the expansion of fluoride-containing cement (2.98%) and MTA (0.07%). In contrast, cements showed a slight shrinkage when immersed in hexadecane, especially fluoride-containing cement.


CONCLUSIONS
The study demonstrated that: (1) the setting time of calcium-silicate cements may be effectively reduced; (2) the expansion is a water dependent mechanism owing to water uptake, because no expansion occurred in cements immersed in oil; (3) a correlation between setting time and expansion in water and PBS exists; (4) fluorine-containing cement showed a significant expansion in water and in PBS; (5) the immersion in FBS/PBS strongly reduced the expansion of MTA and fluoride-doped cement suggesting that fluid contamination (ie, blood) during surgical procedures may greatly affect the expansion of some calcium-silicate cements.
Department of Dental Sciences, Endodontic Clinical Section, University of Bologna, Bologna, Italy. mgiovanna.gandolfi@unibo.it
Maria Giovanna
MG
Gandolfi
Francesco
F
Iacono
Kelli
K
Agee
Francesco
F
Siboni
Franklin
F
Tay
David Herbert
DH
Pashley
Carlo
C
Prati
D017607:Aluminum Compounds / Q000737:chemistry; D000704:Analysis of Variance; D017610:Calcium Compounds / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry; D055598:Chemical Phenomena; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D004338:Drug Combinations; D006882:Hydroxyapatites / Q000737:chemistry; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D012969:Sodium Fluoride / Q000737:chemistry; D013324:Strontium / Q000737:chemistry; D013997:Time Factors
D017607:Aluminum Compounds; D017610:Calcium Compounds; D002130:Calcium Phosphates; D003738:Dental Cements; D004338:Drug Combinations; D006882:Hydroxyapatites; D010087:Oxides; D017640:Silicates; C086631:mineral trioxide aggregate; D012969:Sodium Fluoride; C025700:strontium chloride; C018392:tricalcium phosphate; D013324:Strontium