The safety and efficacy of a home-use carbamide peroxide tooth-whitening procedure were evaluated in a double-blind experimental design. Fifty-two adults were randomly assigned to experimental and control (placebo gel)groups. The products were applied in a custom-fitted tray and used for 5 consecutive nights in accordance with the manufacturer's recommendations. Tooth color changes from baseline were measured with a small-area colorimeter. Concurrently, electric pulp test and peridontal indices were measured. At the end of 6 months, the teeth in the active group had a statistically significant greater mean color change than did the placebo controls. The mean color change differed significantly by tooth type. No statistically significant changes in vitality, sulcus depth, or Gingival Index were found in the treatment group.