Yes, it's recommended to isolate the patient's gums. Only isolate the gum edge in the smile zone to prevent the gel from causing micro burns. We recommend using the MagicDam Gingival Barrier for this purpose. Isolation is particularly important when using the Hydrogen Peroxide Gels. When using our Carbamide Peroxide Gels, teeth whitening can be done safely without isolating the gums, but it should be done with careful application.