Pages 643-648, Language: EnglishCarrillo / Trevino / HaywoodObjective: The purpose of this study was to evaluate the effectiveness of bleaching a nonvital tooth with an open pulp chamber while simultaneously bleaching the other vital teeth with 10% carbamide peroxide. Method and materials: Ten discolored nonvital teeth were treated. Each nonvital tooth was prepared as in the conventional walking bleaching fashion, so that the gutta-percha was sealed from the pulp chamber. The 10% carbamide peroxide was injected into the chamber of the nonvital tooth and loaded into the custom-fitted tray for all teeth. The nonvital teeth were bleached from both the inside and the otuside. The patient closed the orifice with a cotton pellet during the day and changed the cotton pellet after meals. The patient applied fresh solution nightly. Results: All teeth were successfully lightened. The time required to lighten the nonvital tooth was related to the duration of the discoloration. Conclusion: With proper patient selection and education, this technique can provide an effective way to lighten nonvital and vital teeth simultaneously, especially where extended treatment time may be required for difficult discolorations.