In vitro determination and quantification of 30% hydrogen peroxide penetration through dentin and cementum during bleaching.

Bleaching pulpless teeth with 30% hydrogen peroxide was reported to cause external cervical root resorption. It was hypothesized that H2O2 penetrated open dentin tubules to initiate an inflammatory response that could result in root resorption. No direct experimental evidence was provided to support this theory. An in vitro model for determination and quantification of H2O2 penetration during bleaching procedures is suggested. Artificial defects of the cementum covering the cementoenamel junction were performed in 22 extracted human premolars. After 15 minutes of thermocatalytic bleaching, H2O2 could be detected in the medium surrounding all the tested teeth. Cervical root permeability to 30% H2O2 could reach up to 82% of the total amount applied.