The objective of this study was to determine whether removal of calculus was enhanced when proSol PDs 22-4, an irrigating solution, was utilized during ultrasonic cleaning rather than a control (water). Thirty individuals with incipient-to-moderate generalized periodontitis who had not received previous root instrumentation were randomly divided into two equal groups. Baseline examinations included Plaque Index, Gingival Index, Retention Index, pocket depths, clinical attachment levels, bleeding on probing, and Discoloration Index. Immediately after treatment by ultrasonic scaling and the irrigation with either ProSol or water, and 2 weeks postscaling, the clinical parameters were reevaluated. Baseline mean Retention Index revealed no differences between experimental and control groups for any of the surfaces; however, immediately after instrumentation, significant differences were found between treatments in favor of the experimental condition.