Diferentes concentrações de nitrato de potássio na sensibilidade ao clareamento dentário de consultório: estudo clínico randomizado

Abstract

The aim of this controlled, randomized, blinded clinical study was to evaluate the absolute risk, sensitivity intensity and color change to dental bleaching in adults, in the application of different gels based on potassium nitrate and sodium fluoride, from a prospective randomized clinical trial. For this study were selected 78 volunteers who had an equal allocation rate between the groups (G1-control and G2-experimental). In both groups, the different desensitizing gels were applied to the vestibular surface of the anterior superior teeth with the aid of a tray, remaining in position according to the time specified by the manufacturers. In the control group, a gel based on 5% potassium nitrate and 2% sodium fluoride was used, whereas in the experimental group, the gel was based on 3% potassium nitrate and 0.25% sodium fluoride. After removal the desensitizing gel, both groups were submitted to bleaching with 40% hydrogen peroxide gel for 40 minutes. Patients recorded the occurrence or non-occurrence of dental sensitivity (DS) in a sensitivity diary for 48 hours. The Verbal Evaluation Scale (VES) and Visual Analogue Scale (VAS) were used for pain assessment. The valueswere organized into two categories: percentage of patients who presented DS at some time of treatment (absolute risk of sensitivity) and DS intensity. To evaluate the color before the first bleaching session, and after 7, 14 and 28 days, two methods were used: objective evaluation using the spectrophotometer and subjective evaluation using two color scales: Vita Classical and Vita Bleachedguide 3D-MASTER. Data analysis followed the intent-to-treat protocol and involved all randomly allocated participants. The absolute risk of SD was compared using the chi-square test. The McNemar test was used to compare the intensity of SD. The paired Student t test was used to compare the color change. The level of significance in all tests was 5%. Significant bleaching was observed in both groups after 30 days of initial clinical evaluation. The use of different desensitizers in trays did not influence absolute risk and intensity of tooth sensitivity (p> 0.05), although a lower tendency of dental sensitivity risk has been observed for patients who used the nitrate pre-filled tray of potassium and fluorine (experimental group).