Calcium chloride-enriched calcium aluminate cement promotes in vitro osteogenesis.

ABSTRACT

AIM: To evaluate the effects of 2.8% or 10% calcium chloride (CaCl2 ) in calcium aluminate cement (CAC) with either bismuth oxide (Bi2 O3 ) or zinc oxide (ZnO) as radiopacifiers on the progression of osteogenic cell cultures. METHODOLOGY: Rat calvaria-derived cells were grown on Thermanox® coverslips for 24 h and exposed to samples of (i) CACb with 2.8% CaCl2 and 25% Bi2 O3 ; (ii) CACb+ with 10% CaCl2 and 25% Bi2 O3 ; (iii) CACz with 2.8% CaCl2 and 25% ZnO; or (iv) CACz+ with 10% CaCl2 and 25% ZnO, placed on inserts. Nonexposed cultures served as the control. Calcium and phosphorus contents in culture media were quantified. The effects of the cements on cell apoptosis, cell viability and acquisition of the osteogenic cell phenotype were evaluated. Data were compared by Kruskal-Wallis test (α = 5%). RESULTS: CACb+ promoted the highest levels of calcium in the culture media; CACz+, the lowest levels of phosphorus (P < 0.05). CACz+ and CACb increased cell apoptosis (P < 0.05). CACb reduced cell viability (P < 0.05) and the expression of the osteoblastic phenotype. CACz+ and CACb+ promoted greater cell differentiation and matrix mineralization compared to CACz and CACb (P < 0.05). CONCLUSION: For CAC with the lower CaCl2 content, the use of Bi2 O3 was detrimental for osteoblastic cell survival and differentiation compared to ZnO, while CAC with the higher CaCl2 content supported the acquisition of the osteogenic cell phenotype in vitro regardless of the radiopacifier used. Thus, CAC with 10% CaCl2 would potentially promote bone repair in the context of endodontic therapies.