Effect on Oral Health, Phycosocial Impact and Esthetics Perception of Bleaching Teeth

This study was approved by the Ethics Committee of the Faculty of Dentistry (13/18a). This study included 58 patients aged between 18 and 76 years who attended the Operative Dentistry Clinic at the Dental School from the Local University and were eligible for bleaching (see eligibility criteria in the next item). Dental bleaching, free of charge, was suggested to the patients as a way to improve the patient's smile. The patients were informed about the benefits and possible side effects of the procedure in a standardized manner.

Eligibility criteria for dental bleaching Participants were evaluated in a dental chair and after prophylactic dental treatment with pumice and water. To be eligible for dental bleaching, participants should have good general and oral health. Each subject should have at least one central incisor shaded A2 or darker, assessed by comparison with a value-oriented shade guide (Vita classical; Vita Zahnfabrik, Bad Säckingen, Germany). Patients who had undergone previous dental bleaching procedures, under orthodontic treatment, who were pregnant or lactating, or who had bruxism habits were not eligible for dental bleaching. Participants with restorations on the labial surfaces of their anterior teeth, non-carious cervical lesions, veneers, full crowns, gingival recession, spontaneous tooth pain, internal tooth discoloration, and teeth with endodontic treatment or fluorosis were also not included as they could not be immediately eligible for dental bleaching.

Bleaching Procedure For the participants who were bleaching procedure, we made alginate impressions of each subject's maxillary and mandibular arches, and these were filled with dental stone. We did not apply block-out material to the labial surfaces. A 1-mm soft vinyl material, provided by the manufacturer (FGM Dental Products, Joinville, SC, Brazil) was used to fabricate the custom-fitted tray to hold the bleaching gel. The bleaching tray was trimmed 1 mm beyond the marginal gingiva and we delivered a 10% carbamide peroxide (CP) gel (Whiteness Perfect, FGM) to each participant. We give them verbal instructions to apply the product 1 hour daily for 3 weeks. After each application, the patient should remove the tray, wash it with water, and brush teeth as usual. Verbal instructions for oral hygiene were also given, encouraging regular brushing with fluoridated toothpastes that did not contain whitening components.

For these participants, the OHIP-Esthetics, PIDAQ and OES surveys were applied before , one week and one month after the end of the bleaching procedure, and the patient was also given 30 minutes to complete it.

Color Evaluation Color evaluations were performed using subjective and objective methods. For the subjective evaluation, the 16 tabs of the Vita shade Classical guide Vita classical (Vita Zahnfabrik, Bad Säckingen, Germany) were arranged from highest (B1) to lowest (C4) value and used to determine tooth color. Although this scale is not linear in the truest sense, it was treated as continuous with a linear ranking. Two calibrated evaluators with an agreement of at least 85% (using weighted kappa statistics) recorded the shade of the middle area of the labial surface of the upper central right incisor according to the American Dental Association guidelines. Color was registered at baseline and during treatment (after the first, second, and third week of bleaching), and one week and one month after the end of the bleaching protocol to corroborate the effectiveness of bleaching procedure. The color change between baseline and each recall time was calculated as the change in the number of shade guide units (ΔSGU), which occurred toward the lightest end of the value-oriented list of shade tabs. In case the operators disagreed on the color, a consensus was reached before dismissing the patient.