Clinical Trials on the Use of Whitening Strips in Children and Adolescents

Donly KG, Gerlach RW

A desire for whiter teeth has led to a more convenient method of bleaching—the strip-bleaching system. Previously, dentists used plastic trays filled with a bleaching agent that were worn overnight and resembled a mouth guard. These clinical trials indicated that strip-bleaching systems—where a gel containing hydrogen peroxide is delivered via a flexible and disposable polythene strip—are a viable and effective means of tooth whitening in children and adolescents. Materials and Methods Strip-based vital bleaching was evaluated in a series of three randomized, controlled clinical trials conducted by researchers at the University of Texas and Procter & Gamble. Each trial lasted eight weeks. Two different peroxide concentrations were evaluated: 5.3 percent hydrogen peroxide1 and 6.5 percent hydrogen peroxide2. Study participation was limited to preteen and teenage volunteers who desired tooth whitening and had an average tooth shade of "A2" or darker as measured using a standard 16-step shade system3. Subjects were instructed to wear the strips twice a day for 30 minutes and evaluated every two weeks. The maxillary arch was treated for the first four weeks, and the mandibular arch was treated for the last four weeks. Effectiveness was measured from digital images of the teeth collected at baseline and at follow up. Color values were determined for each tooth pixel in the image in international standard, three-dimensional space for light-to-dark (L*), green-to-red (a*), and blue-to-yellow (b*). Color change (ÄL*, Äa*, and Äb*) with bleaching was determined by comparing each post treatment visit to baseline, with negative Äb* (reduction in yellow) and positive ÄL* (increased brightness) representing tooth whitening. Results A total of 132 children and adolescents ranging in age from 10 to 18 were treated. Much of the whitening benefit was observed after the first two weeks of treatments. Both the 5.3 percent and 6.5 percent hydrogen peroxide strips yielded significant tooth whitening (P<0.0001) after 14 days. However, individuals treated with the more concentrated strips experienced significantly greater reduction (P<0.03) in yellowness of approximately 0.8Äb* compared to the lower concentration strips. Only baseline (starting) color and arch were significant contributors to the primary response variable, reduction in yellowness (Äb*). The whitening response was greatest among children and teenagers who started with more yellow teeth. On average, the data suggested that for each unit of increased yellowness, individuals should expect approximately 0.3 units additional improvement in Äb*. Although both arches improved in color, the response in the maxillary teeth was significantly better (P<0.0001) than in the mandibular teeth. The primary complaints about the whitening strips were tooth sensitivity and oral irritation, though no subject discontinued the treatment early due to an adverse event. Eighteen subjects (14% of the study population) reported oral irritation, and 30 subjects (23%) reported tooth sensitivity. In most cases, these events were symptomatic only, mild in severity, and were relieved upon discontinuance of the whitening agent. Conclusion Typically, children are not considered for esthetic treatments such as vital bleaching. However, the authors concluded that children and adolescents age 10-18 represent a population that can benefit from using hydrogen peroxide whitening strips. Gen Dent 2002 May-Jun;50(3):242-5. 1. Crest Whitestrips, Procter & Gamble, Cincinnati, Ohio 2. Crest Professional Whitestrips, Procter & Gamble 3. Vident, Brea, California Return to Top