Tooth Sensitivity: The most common side effect is tooth sensitivity. Sensitivity is directly related to the concentration of hydrogen peroxide. Postoperative care of using a fluoridated mouth rinse or ACP-CPP should be taken, to promote remineralization of the enamel surface.
Gum irritation: This is possible if the bleaching agent or if the margins of an ill fitting tray comes in contact with unprotected gum tissue. Such lesions should be treated by copious rinsing with water. More severe ones should be treated with topical application of anaesthetic gels.
If any of these side effects continue, then you should visit your dentist.