Water sorption and solubility of different calcium hydroxide cements

Abstract

Objectives: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.Material and 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°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°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.

Calcium hydroxide liners: a literature review

“…Calcium hydroxide liners must not be left on the margin of the prepared cavity or the margin will not be properly sealed because the liner is soluble in water 19. It has high solubility and water sorption,39 which may result in softening of the liner and in material loss under poorly sealed tooth–restoration interface where the oral fluids can penetrate through and partially or totally dissolve this pulp-protecting material 9. This was previously described in the literature as the “Disappearing Dycal” syndrome 7.…”

“…A visible light-cured (VLC) calcium hydroxide liner consists of calcium hydroxide and barium sulfate dispersed in a urethane dimethacrylate resin containing initiators and accelerators activated by visible light 31. The fact that this material is based on polymeric resins allows for bonding between it and the overlaying composite restoration 39,56. It should be noted that if subsequent use of a dentine-bonding agent is desired, the VLC liner should only be applied on the deepest (<1 mm remaining) dentine, leaving the rest of the cavity surface free for bonding.…”

Bismuth subsalicylate as filler particle for an experimental epoxy-based root canal sealer

“…According to ISO6876 13 , the endodontic sealer should not shrink more than 1% and swell more than 0.1% to avoid gaps between sealer and dentin. In the present study, the experimental endodontic sealers presented swelling higher than 0.1% 13 accordingly to commercial available sealers [22][23][24] .Any uptake of water is determined by the intrinsic hydrophilicity of the copolymer, the type and amount of filler particles 25 and it could result in lower mechanical properties of root canal sealers 21,26 .The water sorption could also lead to degradation of the sealer, due to the unreacted monomers leach through porosities 21 .According to ISO 4049 14 , the water sorption of the resin-based material cannot be more than 40 µg/mm 3 and the water solubility must be up to 7.5 µg/mm 3 . In the present study, the water sorption of the sealers with 20 wt% of bismuth subsalicylate presented water sorption in accordance to the requirement.…”

Evaluation of the antibacterial efficacy of different bioactive lining and pulp capping agents

“…The mold was filled with the cement then covered with a polyester strip and another glass slab. The material was cured according to the manufacturer's instructions for 40 s from top and bottom to ensure proper curing [20].…”