Some effects of Ledermix® paste and Pulpdent® paste on mouse fibroblasts and on bacteria in vitro

Dilutions of Ledermix paste, Pulpdent paste and a mixture of equal parts by weight of Ledermix paste and Pulpdent paste were added to in vitro cultures of mouse fibroblasts or bacteria for 24 h, and various cell functions were then examined: mitosis in and survival of fibroblasts, and survival of Lactobacillus casei or Streptococcus mutans. Ledermix was found to reversibly inhibit mitosis while present in the concentrations range 10(-3) to 10(-6) mg/ml. Mixing with Pulpdent did not modify this antimitotic effect. Ledermix killed mouse fibroblasts at 10(-3) mg/ml and above, while Pulpdent killed at 1 mg/ml and above. The toxic effect of Ledermix was slightly inhibited by mixing it with Pulpdent. Ledermix killed S. mutans at about the same concentration at which it killed the mammalian cells, but required a one thousand-fold greater concentration to kill L. casei. Pulpdent killed both L. casei and S. mutans at approximately one-fifth of the concentration at which it killed the mammalian cells. Pulpdent slightly potentiated the antibacterial effect of Ledermix. The pH of Pulpdent was reduced by approximately 0.3 units by mixing with Ledermix. The present data showed that the 50:50 mix of Ledermix and Pulpdent retained the properties examined that are thought to be of therapeutic benefit, while not increasing the toxicity of the component parts to mammalian cells.