Effect of Daily Usage Time of 4% Hydrogen Peroxide on the Efficacy and Bleaching-induced Tooth Sensitivity: A Single-blind Randomized Clinical Trial

Abstract

Clinical Relevance Although color change was slightly lower in a 3-week 30-minutes/day protocol, than in the 120-minute protocol, this could be compensated by an extra week of bleaching. The advantage of the shorter protocol is the reduced daily application, making the procedure more comfortable for the patients. SUMMARY Objective: Compare the risk/intensity of tooth sensitivity (TS) and color change of a 30-minute vs. the recommended 120-minute application time of 4% hydrogen peroxide (HP) for at-home bleaching. Methods: A single-blind, parallel, randomized clinical trial was conducted with 92 adult patients with caries and restoration-free anterior teeth A2 or darker, randomly allocated to two groups. Bleaching trays containing 4% HP were used for three-weeks. A four-week regimen was also offered to the patients for the 30-min group after the end of the 3-week protocol. The color change was assessed with the Vita Classical (VITA Zahnfabrik, Bad Säckingen, Germany) and Vita Bleachedguide shade guides (VITA Zahnfabrik) and the Vita Easyshade spectrophotometer (VITA Zahnfabrik) at baseline, weekly, and 30 days after the bleaching. The absolute risk and the intensity of TS were assessed daily using the 0-10 visual analogue scale (VAS) and 5-point Numerical Rating Scale (NRS) scale, and patient satisfaction was recorded with a Likert 0-7 scale. Risk of TS (Fisher’s test), intensity of TS in NRS scale (Mann-Whitney test), VAS scale (t-test), and a color change (t-test) were compared. Results: The 30-minute group saw color change of around 1 SGU inferior to the 120-minute group in all-time assessments (p<0.05). After an extra week of bleaching, mean color change was similar (p>0.05). Patient satisfaction was high for both groups (p>0.05). Conclusions: A four-week protocol of at-home dental bleaching with 4% HP for 30 minutes/day whitened teeth similarly to the 120 minutes/day protocol, with low intensity of dental sensitivity and high patient satisfaction.

Effects of microabrasion association to at‐home bleaching on hydrogen peroxide penetration and color change

“…25 This promotes an inflammatory response, 26 causing the most common effect reported in clinical studies, which is tooth sensitivity. [27][28][29] Because both PH concentrations were applied for the same amount of time, we expected that the higher the concentration of HP, the greater the amount of HP inside the pulp cavity, 17,30 as observed in the present study. However, regardless of the HP concentrations used, there was a significant increase in HP inside the pulp cavity when MA was applied prior to at-home bleaching.…”

“…However, HP and its by‐products can reach the pulp cavity within 15 min 25 . This promotes an inflammatory response, 26 causing the most common effect reported in clinical studies, which is tooth sensitivity 27–29 …”

Evaluation of application protocol of the 4% hydrogen peroxide for at‐home bleaching: A randomized clinical trial

“…The protocols vary in time usage, frequency, and duration of the treatment. There are reports of tray use for reduced periods of 30 min, 1 or 2 h, 19,22 or for more extended periods such as 6 h or even overnight use. 23,24 In addition, the frequency of the tray use ranged from one to three daily applications 16,25,26 in protocols that lasted 28 days 27 or even 6 months.…”

“…5 Therefore, several alternatives have been launched in the market to simplify the bleaching procedure in terms of application time. [14][15][16][17][18][19] One of the most interesting is to used low concentrated hydrogen peroxide with concentrations varying from 4% to 10% for the athome protocol. Hydrogen peroxide is usually recommended for use over shorter periods than carbamide peroxide is.…”

“…16,20,21 Recommendations of 30 min to 2 h daily, as well as more extended periods of time can be seen in the literature. 17,19,[22][23][24] Also, there are a huge variation in the frequency of the tray use. 16,[25][26][27][28] It is known from laboratory investigations that 1 h after application, the amount of active hydrogen peroxide in at-home hydrogen peroxide gels is reduced by approximately 30% to 50%.…”