The clinical effectiveness of povidone-iodine as a disinfectant in teeth isolated by a rubber dam was compared to the effectiveness of isopropyl alcohol. The results showed no statistically significant difference between povidone-iodine or isopropyl alcohol for disinfecting intact enamel surfaces. When a scrub-type application of povidone-iodine was used, preliminary removal of plaque with pumice did not increase its effectiveness. Both agents were significantly less effective at 15 minutes after application than they were at 90 seconds after application.