Human Periodontal Ligament Cells Response to Commercially Available Calcium Hydroxide Pastes

Several studies have shown that calcium hydroxidebased medicaments have a cytotoxic effect on human cells. The purpose of this study was to evaluate the cytoxicity of several calcium hydroxideproducts on periodontal ligament (PDL) cells. Calcium hydroxide powder (Avantor Performance Materials Inc.), Calasept® (Nordiska Dental AB), Metapaste® (Meta Biomed Co., Ltd.), Vitapex® (Neo Dental International Inc.), Ultracal® (Ultradent Products, Inc.), and Pulpdent® (Pulpdent Corporation) products were tested. PDL cells were exposed to various concentrations of calcium hydroxidefrom each product (1.0, 0.5, 0.25, and 0.125 mg/mL). Cell viability was measured after 24 h and 48 h by Cell Proliferation Assay. All materials tested had a more toxic effect on PDL cells after 48 h.At 24 and 48 h, Metapaste® was the most toxic regardless of concentrations used. Products with a1.0 and 0.5 mg/mL concentration hadstatistically significant more cytotoxic effectswhen compared to the negative control. Pure calcium hydroxide and Calacept® induced 35% cell death at a 1 mg/mL concentration and 15-20% cell death at 0.5, 0.25, and 0.125 mg/mL after 24 h. Pulpdent® andUltracal® induced 30-35% cell death at a 1 mg/mL concentration and its effect diminished at 0.25 and 0.125 mg/mL at 24 h. The Vitapex® preparation induced 20% PDL cell death at 24 h regardless of the concentration and was the least toxic significantly at 1 mg/ mL compared to other brands, except Pulpdent®, at the same concentration at 24 h.All calcium hydroxideproducts showed evidence of cytoxicity on PDL cells, with Metapaste being the most cytotoxic. The cytotoxicity was related to concentration and exposure time. Pulpdent® and Ultracal® had excellent biocompatibility at lower concentrations.