Abstract
Objective: The purpose of this study was to evaluate tooth whitening efficacy of self-applied 2.6% and 2.9% hydrogen peroxide strip and their safety on tooth and gingival tissues. Methods: Among 101 subjects who agreed to purpose of this study, 98 healthy people aged 20-30 years old, had 6 natural maxillary anterior teeth, and at least 2 which of them were graded in VITAPAN 3-D $MASTERR^\circledB$ shade guide(VITA Zanfabrik, Germany) 3rd groups or darker were selected. Informed consent from all subjects were obtained before experiment and subjects were assigned randomly to control and experimental groups by matching on tooth color in a double blind design. Experimental tooth whitening strips used in this study consisted of base polymer as polyvinyl cellulose and whitening material as 2.6 and 2.9% hydrogen peroxide respectively. Only hydrogen peroxide was excluded in the control strips. The subjects belong to experiment group I used 2.6% hydrogen peroxide strip for 30 min, twice a day, and experiment group II and placebo control group used 2.9% hydrogen peroxide strip for 60 min, once a day during 28 days. Total functional times were same in all groups. Whitening effect of strips in maxillary 6 incisors were measured in both methods during 4 weeks from baseline. In CIE color space, ${\Delta}L^*,\;{\Delta}a^*,\;{\Delta}b^*\;and\;{\Delta}E^*$ from baseline were calculated using colorimeter (Minoltar CR-321, Japan) in every 7 days, and trained examiner select tooth shade in every 7 days using VITAPAN 3-D MASTERR shade guide. Trained examiner also checked the Loe and Silness gingival index modified for six maxillary anterior teeth were used for measuring gingival irritation of the strip in every 7 days. And tooth hypersensitivity, burning sensation on gingival tissue and tongue, eruption on the tongue were surveyed by using ten scale self-administered questionnaires. All data were analyzed by analysis of variance method. Results: Average ${\Delta}E$ score of 2.6% hydrogen peroxide strip group is 1.83 in 2 weeks and 2.38 in 4weeks, and average ${\Delta}E$ score of 2.9% hydrogen peroxide strip group is 1.9 in 2 weeks and 2.48 in 4weeks. ${\Delta}E$scale was significantly different with control group from 1 week and increased as time elapsed. Tooth shade of experimental groups were increased to 19th grade of 2R2.5 or 2L2.5 in 2 weeks, showed statistically difference with control strip group, and average tooth shade of experimental group were more increases 5 or 6 grades to 20th or 21th grade of 2L2. 5 or 2M3 In 4 weeks. Gingival inflammation level, feeling of hypersensitivity on teeth and feeling of eruptions on tongue of experimental groups were not differ from control groups and did not changed through the experimental duration and they were very low level in all groups, Burning sensation level was very low, but there were statistically significant difference on 2.6% hydrogen peroxide strip group with control group but burning sensation level was tolerable level for all subjects. Conclusion: Both of 2.6% and 2.9% hydrogen peroxide strips had tooth brightening effect and there were no signs of irritation on tooth and gingival tissue. This results suggested that both of 2.6% and 2.9% hydrogen peroxide strips can be used conveniently for tooth whitening.