Objective: The study evaluated the longevity, effectiveness, safety, and impact on the oral health-related quality of life of in-office dental bleaching using low-concentration hydrogen peroxides.
Materials and methods: Randomized, parallel, and double-blinded clinical trial was performed with 54 participants using 6% or 15% hydrogen peroxide (HP) in-office bleaching activated via hybrid LED/laser light. Tooth color was evaluated at baseline (T1), 1 week of bleaching (T2), 2 weeks of bleaching (T3) and 1 week (T4) and 6 months (T5) after finishing the bleaching using the Classical Vita™ scale and spectrophotometer. Tooth sensitivity and gingival irritation were measured with Visual Numeric Scale and Modified Gingival Index. The impact on quality of life was evaluated using the Oral Impact on Daily Performance. The data were analyzed using the Friedman, Mann-Whitney, and McNemar tests (p < 0.05).
Results: The group HP15% presented significant color change (ΔE) from T1 to T4 (p = 0.002) and T1 to T5 (p < 0.001). Parameters L, a*, and b* differed significantly at T3, T4, and T5 compared T1 for both groups. At 6-month follow-up, 57.1% of HP6 and 43.7% of HP15% participants migrated from B1 to a darker color. No significant differences were observed between the groups in tooth sensitivity, gingival irritation, or impact on quality of life.
Conclusions: Both agents showed bleaching effectiveness, but HP15% presented greater color stability than HP6%, at 6-month follow-up. The agents showed low levels of tooth sensitivity, gingival irritation, and did not affect the oral health-related quality of life of the participants.
Clinical relevance: Despite the greater presence of sensitivity during treatment compared with 6% hydrogen peroxide, 15% hydrogen peroxide demonstrated better bleaching effectiveness, and greater color stability at the end of bleaching and at 6-month follow-up. The use of 15% hydrogen peroxide presents more suitable results.
Keywords: Dental bleaching; Hydrogen peroxide; Longevity; Quality of life.