Purpose: This study determined hydrogen peroxide release into the oral cavity during use of different home bleaching products and compared them with accepted safe levels.
Methods: Determination of peroxide in saliva was performed with peroxidase, phenol and 4-aminoantipyrin in a photometric method. Upper jaw incisors were bleached with individual trays charged with 350 mg Opalescence 10%, Opalescence 15% (OP) and Vivastyle (V). Additionally, Whitestrips (WS) designed for upper or lower jaw were used. All systems were adopted by five subjects for 30 minutes on different days. Whole saliva was collected at 2-minute intervals during the first 10 minutes of bleaching and every 5 minutes thereafter.
Results: Highest release of peroxide was found for all products in the saliva sample collected initially after application of the bleaching agent. Total amount of peroxide released into saliva during 30-minute bleaching period was 0.78+/-0.45 for Opalescence 10% and 1.52+/-0.44 mg for Opalescence 15%. Significantly more peroxide was released from Vivastyle (2.67+/-1.03 mg) and from Whitestrips (upper: 3.25+/-5,65, lower: 2.09+/-0.34 mg). A significantly smaller fraction of the charged peroxides was released into saliva from individual trays than from Whitestrips during the 30-minute use time. From the peroxide loaded in the trays or strips the following fractions were released during the application period: Opalescence 10% (6.4+/-3.7%), Opalescence 15% (8+/-2.4%), Vivastyle (18.6+/-8.5%), upper Whitestrips (30.4+/-4.9), lower Whitestrips (27.4+/-4.4%). In terms of amount/kg body weight the bleaching systems led to a single exposure of 0.013-0.056 mg/kg which is distinctly less than the maximum safe daily dose of 0.26 mg/kg/day if calculated for a small person (58 kg/128 lbs).