Clinical Efficacy of In-office Bleaching With Different Concentrations of Hydrogen Peroxide

"After the lip retractor (OptraGate, Ivoclar Vivadent, Schaan, Liechtenstein) was placed, the gingival barrier protection (Biowhiten, Biodent Ltd., İstanbul, Turkey) included in the products was applied to the upper and lower arches from premolar to premolar at the beginning of each session and removed after each treatment. The bleaching gels were applied according to the manufacturer and removed after the recommended period with a disposable surgical saliva ejector, cleaned with gauze and washed with air-water spray. Two bleaching sessions were performed at a 1-week interval. Participants were advised to maintain regular oral hygiene by brushing with toothpaste that does not contain desensitizing or whitening ingredients.~HP18 is applied in 5 applications of 10 minutes per session. HP25 is applied in 3 applications of 15 minutes per session. HP40 is applied in 3 applications of 15 minutes per session."