Inclusion Criteria:  Participants of 18-55 years old Participants with good general and oral health. Participants did not undergo any bleaching procedure before. Participants with caries-free maxillary six anterior teeth without any restorations. Participants do not suffer of periodontal diseases. Participants willing to assess and sign the informed consent form.  Exclusion Criteria:  Participants with anterior restorations. Participants with dental prosthesis of the anterior teeth. Participants with orthodontics brackets. Participants with severe internal teeth discoloration as in cases of tetracycline stains, fluorosis or non-vital teeth. Smoking participants. Breastfeeding and pregnant women. Participants with gingival and bone recession. Participants with dental erosion, dentin exposure, and cracked teeth or any other pathologic condition that may elicit teeth sensitivity. Participants having their teeth bleached. Participants taking analgesic or anti-inflammatory drugs. Participants with bruxism habits are excluded from the study.