Microcomputerised tomography evaluation of 10% carbamide peroxide applied to enamel

Objectives. There is still some controversy in the dental literature whether carbamide peroxide bleaching causes demineralization of teeth. One of the reasons for this controversy is that there is as yet no reliable, non-destructive in vitro metod for assessing mineral loss in bleached teeth. The objective of this study was to investigate the possible demineralization effect of 10% carbamide peroxide bleaching agent on enamel and dentine non-destructively. Methods. mu CT images were obtained of 12 human molar tooth sections. These sections had 10% carbamide peroxide applied for eight hours a day over a period of 15 days. Further tomographic images were obtained and the mineral content prior to and post bleaching assessed. Results. A total of 144 regions were evaluated using the image processing language available in the work station. The application of 10% carbamide peroxide was found to cause demineralization of the enamel extended to a depth of 50 gm below the enamel surface (Paired t-test, p<0.05). Conclusions. This study confirmed that mu CT was indeed a highly suitable method for assessing mineral content of dental enamel after bleach application. It is recommended that application of bleaching agents should be carefully considered in patients susceptible to caries and tooth wear. (C) 2005 Elsevier Ltd. All rights reserved.