Water sorption and solubility of different calcium hydroxide cements.
OBJECTIVE
Calcium hydroxide cements have been largely used in deep cavities due to their abilities to stimulate dentin formation. However, their resistance can be relatively low and their solubility relatively high, in many instances. This study evaluated water sorption and solubility of different calcium hydroxide cements, in order to show alterations that may reduce their effectiveness.


METHODS
Five discs (20 mm in diameter and 1.5 mm thick) of three different materials (Biocal, Dycal and Hidro C) were prepared with the aid of a ring-shaped metallic matrix. After being stored at 37 degrees C for 24 h, the discs were weighed on a precision weight scale, dehydrated and weighed again. Immediately after weighing, discs were stored for a week in 50 mL of distilled water at 37 degrees C and, then, weighed again, dehydrated and submitted to a new weighing. The loss of soluble material and its water sorption was obtained from the difference between the initial and the final dry mass of each disc, after 1 week of immersion in water. Data were analyzed for significant differences by two-way ANOVA and Tukey's test (p<0.05).


RESULTS
Mean water sorption values (g) +/- standard deviation and percentage (%), for each evaluated cement, were: Biocal (0.006 +/- 0.001 / 2.15); Dycal (0.016 +/- 0.004 / 5.49); and Hidro C (0.025 +/- 0.003 / 8.27). Mean solubility values (g) +/- standard deviation and percentage (%), for each evaluated cement, were: Biocal (0.002 +/- 0.001 / 0.72); Dycal (0.013 +/- 0.004 / 4.21); and Hidro C (0.023 +/- 0.004 / 7.65).


CONCLUSIONS
Biocal absorbed less water and was less soluble than the other evaluated cements; Hidro C exhibited the highest water sorption and solubility values; and there were significant differences among all evaluated experimental groups.
Francisconi
Luciana Fávaro
LF
Department of Operative Dentistry, Endodontics and Dental Materials, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil.
de Freitas
Anderson Pinheiro
AP
Scaffa
Polliana Mendes Candia
PM
Mondelli
Rafael Francisco Lia
RF
Francisconi
Paulo Afonso Silveira
PA
D000042:Absorption; D000327:Adsorption; D002126:Calcium Hydroxide / Q000737:chemistry*; D003738:Dental Cements / Q000737:chemistry*; D003890:Desiccation; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D008903:Minerals / Q000737:chemistry; D012995:Solubility; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry*
D003738:Dental Cements; D008903:Minerals; D014867:Water; C025702:Dycal; D002126:Calcium Hydroxide