The purpose of the present study was to evaluate clinically the effect of an anaesthetic gel (lidocaine 20 mg/g as active agent) on pain sensitivity and early wound healing following nonsurgical periodontal therapy. A total of 40 patients with chronic periodontitis were enrolled in this randomized, split-mouth, double-blind, placebo-controlled clinical trial. Each subject had 3 sites in each of 2 contra-lateral jaw quadrants with a probing pocket depth (PPD) of > or = 5 mm and bleeding on probing (BOP+). All experimental sites received scaling and root planing without local anesthesia followed by irrigation with sterile saline and assessment of pain sensitivity using a standardized Visual Analogue Scale (VAS). After treatment, the patients randomly received the active or placebo gel into the periodontal pockets and overall pain was again assessed immediately after debridement and after 10, 20 and 30 minutes. The VAS showed a statistically significant (p < or = 0.0001) reduction in reported pain, favoring the active gel over the placebo at all 3 different points in time. After 30 minutes the median VAS score was 0.3 in the Dynexan group as opposed to 1.7 in the placebo-treated group (p < or = 0.0001). In terms of wound healing no differences were found between the test and control sites after 1 week. The results of the study showed that the anaesthetic gel was statistically more effective than the placebo in reducing pain following nonsurgical periodontal therapy. However, in terms of early wound healing no significant differences were seen between the two treatment sites.