Influence of teeth, plaque and dentures on the retention of chlorhexidine in the human oral cavity

Abstract The retention of chlorhexidine in the oral cavity after rinsing with 10 ml 0.2 % [¹⁴C]-chlorhexidine-digluconate for 1 min was found to be 3.8 mg (S.D. = 1.4 mg) in a group of 12 edentulous patients. By comparison, the mean oral retention in 10 dental students with cleaned and polished teeth was 4.6 mg (S.D. = 0.7 mg). Measurement of the retention in 6 subjects before and after extensive tooth extractions showed no major influence of the teeth on the chlorhexidine retention. Plaque accumulation for 6 d increased the mean Plaque Index from 0 to 0.82 (S.D.=0.35). The corresponding mean oral retention increased significantly from 4.6 mg (S.D.=0.7 mg) to 5.6 mg (S.D.=1.1 mg). Chlorhexidine was readily bound to acrylic resin dentures. A mean binding of 4.2 mg (S.D.=2.0) after 16 min immersion in 110 ml 0.2% chlorhexidine solution was found. The [¹⁴C] activity of the saliva showed a sharp fall during the first few hours after insertion of the dentures, followed by a slow release, with activity still present after 24 h.