Purpose: To determine whether ingestion of a tooth whitener containing 6% hydrogen peroxide as bleaching agent affected the gastric mucosa of adult, female laboratory rats.
Materials and methods: Thirty-six fasting rats were intubated with a single bolus (5 g/kg body weight) of the tooth whitener Natural White which contains 6% hydrogen peroxide. Thirty-two control rats received deionized water. Rats were necropsied 15 minutes, 2 hours, 1 and 2 weeks after whitener ingestion. The gastric mucosa was examined histologically and blood hematocrit, glucose, BUN, and bilirubin measured.
Results: Six of the 36 rats died within 2 hours of receiving whitener. Within 15 minutes of whitener ingestion, stomachs were grossly bloated with gas. Histological observation showed that gastric mucosal cells were vacuolated and gastric glands dilated. After 2 hours, gastric epithelial and glandular cells had sloughed off into the gastric lumen. Mean blood glucose and hematocrit were significantly (P < 0.05) elevated (233 +/- 41 mg/ml and 50.5 +/- 0.9%) over mean control values (129 +/- 8 mg/ml and 42.8 +/- 2.4%). Within 1 week, the stomachs of experimental rats were no longer bloated, the gastric mucosa appeared normal histologically, but mean blood hematocrit was significantly (P < 0.05) decreased (38.0 +/- 1.5%) from mean control value (43.3 +/- 0.5%). There were no significant differences in mean blood values 2 weeks after whitener ingestion.