The aim of the present study was to assess the influence of a 1-month period of chlorhexidine digluconate (CHX) rinses on the remodelling activity of periodontal tissues adjacent to an extraction wound. From 12 patients assigned to the test group rinsing 2 x daily with 15 ml of 0.12% CHX solution (Peridex) starting 2 days after tooth extraction and from 11 patients assigned to the control group rinsing with a placebo solution, standardized radiographs were available taken immediately after tooth extraction and 1, 2, 3 and 6 months thereafter. Computer assisted densitometric image analysis (CADIA) was applied in order to quantify changes in density during the healing phase after tooth extraction. Regions of interest (ROI) were chosen for CADIA covering supracrestal periodontal soft tissue adjacent to the extraction wound. ROIs were also defined on crestal alveolar bone adjacent to the extraction wound. In the active group, 15/20 sites demonstrated an increase in alveolar bone density between months 1 and 6 (mean CADIA value 6.7 +/- 10.0), whereas in the control group 11/21 sites demonstrated a loss in density (mean CADIA values -1.4 +/- 10.5). Similar observations were made when the ROIs covering supracrestal periodontal tissues were analyzed (mean CADIA values 7.8 +/- 8.4 for the experimental group and -0.3 +/- 10.5 for the control group). These differences were statistically significant (p < 0.04). The digitized series of standardized radiographs were also evaluated for changes in bone height. The distance from the alveolar bone crest to reference points were measured in mm within the baseline: the 1, 2, 3 and 6 month radiographs.(ABSTRACT TRUNCATED AT 250 WORDS)