“…Dental whitening in the office consists of applying gels based on carbamide peroxide above 20% and hydrogen peroxide above 10% in the dental office. This technique has the advantage of being directly controlled and supervised by the professional, so that there is no contact with soft tissues and gel ingestion, does not depend on the collaboration of the patient and exhibits immediate results, and can be performed in just one clinical session, [3,4,8] therefore, it is indicated for patients who want fast, effective and stable results and who prefer not to use the home whitening tray.7,9 For the office dental whitening procedure, the soft tissues are protected prior to application, so that no gingival inflammation, burns and ulcerations in the soft tissues occur and, only after this step, the whitening gel is applied on the teeth surface [2,[9][10][11]. Tooth whitening occurs when whitening agents penetrate enamel and dentin, releasing free oxygen radicals that break the double bonds present in the organic compounds responsible for the color change and transform the pigment molecules into smaller, less complex and, consequently, more clear [1,3,6,7,10,12].…”