Studies have shown that when properly done on patients with no active decay, there is no damage. According to the American Dental Association, damage to teeth after whitening can occur with overuse of at-home whitening systems as these are administered without the supervision of a dental professional. Damage could also occur in the enamel if inferior whitening solutions are used. Some patients experience sensitivity in their teeth or irritation to the gums for a short time immediately after treatment; however, symptoms usually resolve quickly and no permanent damage occurs.