Purpose: The purpose of this study was to investigate the ion release from titanium casts in solutions of mixed organic acids and to reconsider the possibility of allergic reactions to titanium.
Methods: Cast specimens were made from commercially pure titanium. For the immersion solutions, we prepared two types of organic acid solutions, one mixed with organic acids contained in whole stimulated saliva at two different dilutions, and the other, a lactic acid solution. Following immersion, the amounts of dissolved titanium ions, weight loss of the casts, and micrographs of the specimen surfaces were examined.
Results: There were significantly larger amounts of dissolved titanium ions in the mixed organic acid solutions than in the lactic acid solution. There was also a significant difference in the weight loss values between the immersion solutions (p < 0.0001), but the significance level was different from that of the difference in the quantity of ion elution.
Conclusion: The results suggested that a much larger quantity of ions is released from titanium casts attached in the oral cavity than has been reported previously, and that it is necessary to consider the possibility of allergic reactions to titanium casts.