Comparison of Tooth Whitening Efficacy between Gel and Strip with Light Activator

Abstract

The study aimed to compare the whitening efficacy of a strip and gel containing 2.9% hydrogen peroxide, using a tooth whitening light activator. The whitening effect was compared through in vitro and in vivo studies. In the in vitro study, we used stained hydroxyapatite (HAP) specimens as artificial teeth. HAP specimens were made using HAP powder and polyvinyl alcohol solution, and stained by modified Stookey's method. A whitening gel and whitening strip were applied to the respective specimens for 20 minutes, with a light activator. The color changes were measured using a colorimeter. In the in vivo study, one group (test 1) used the gel with a light activator and the other group (test 2) used a strip with the same activator for 15 minutes a day, for four consecutive days. An organoleptic evaluation using a Vita shade guide and instrumental evaluation using a Shade eye-NCC (Shofu Co., Japan) were performed. The color change values (∆E*) in the in vitro study revealed the strip with the light activator to be more effective than the gel with the same activator (p＜0.001). In the in vivo study, even though there was no significant difference between the groups with respect to the ∆E*, using either the Shade eye-NCC or the Vita shade guide, the change in yellowness (∆b*) was statistically significant (p=0.024). In conclusion, test 2 group that used 2.9% hydrogen peroxide strip with a light activator, showed a tendency towards increased whitening than test 1 group that used the gel with the same activator; however further studies are needed to validate the above finding.

Surface Damage and Bleaching Effect according to the Application Type of Home Tooth Bleaching Applicants

“…Previous research from Monaghan et al 28) also demonstrated, following a 2-week experiment, that bleaching effect was significantly greater with longer exposure. However, in this study, the difference in △E * ab values of the specimens exposed for the recommended time and those exposed for In terms of bleaching effect based on application type, a previous study by Kim et al 16) demonstrated that the Patch-type had an approximately 27% greater bleaching effect than the Gel-type. It was also reported that such results could be attributed to the fact that the Patch-type was more thoroughly adhered to the tooth surface, delivering the bleaching agent more effectively, in one direction.…”

“…In a previous study by Zantner et al 14) , as well, a greater reduction in microhardness was observed in the use of 16) . It is presumed that the Patch-type products used in previous studies also demonstrated significantly greater surface damage than Gel-type products for the same reasons, whereas a statistically significant difference was not observed in this study due to its use of in vitro experiments where the condition of the oral cavity could not be perfectly reproduced.…”

“…The reason why the color change values were greater than the standards put forth by Gross and Moser 26) in the two studies may be attributed to the fact that the specimen used had undergone an artificial tooth surface staining process. For instance, in a previous study by Kim et al 11) , where the bleaching process took place without previous staining, the average color change was △E * ab= 3.40, but in the case of another study by Kim et al 16) that used specimens that had undergone a staining process, a greater color change of △E * ab=34.02 was detected.…”

“…However, Park et al 15) compared products with different components-a 2.5% hydrogen peroxide patch and a 10% carbamide peroxide gel. Kim et al 16) , on the other hand, demonstrated only positive bleaching effects as the authors were affiliated researchers of the manufacturer. Needless to say, risks such as surface damage were not included in the studies.…”