The purpose of this clinical investigation was to determine if periodontal treatment consisting of scaling, root planing, and periodontal surgery produced any change in pulpal or root sensitivity. Ten patients were tested, with a total of 84 observations. There were 42 periodontally treated teeth, with 42 contralateral teeth serving as control specimens. The teeth were evaluated with stimuli from an electric pulp tester, cold, and air. The electric pulp tester was found to be reliable in assessing the pulpal sensitivity. Neither the amount of periodontal destruction nor the extent of periodontal treatment had any effect on the pulp. Scaling and root planing had no significant effect on root sensitivity. Periodontal surgery was directly related to root sensitivity in terms of the extent of root surface exposure. An association was observed clinically between plaque accumulation after periodontal surgery and root sensitivity.