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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. [ABSTRACT FROM AUTHOR]

The binding of chlorhexidine to proteins in vitro has been shown to involve albumin in both serum and saliva. The binding, which is pH- and concentration-dependent, occurs both to proteins remaining in solution and to proteins precipitated during the reaction. Both reactions are reversible, although that to precipitated protein apparently involves a stronger binding. If the latter can be correlated to the in vitro situation, it is suggested as a possible explanation of the extended retention of chlorhexidine in the mouth despite the rather rapid turnover of saliva. [ABSTRACT FROM AUTHOR]

Retention of Cu and Zn in the mouth after rinses with known volumes of aqueous solutions of the metal salts was measured by atomic absorption. The mean amounts retained in 10 subjects were 0.02 mg Cu and 0.22 mg Zn. These values represent approximately 31% of the Cu and 15% of the Zn originally in the rinse. The intraindividual variation (s.d.), estimated by three mouthrinses at weekly intervals in three subjects averaged 2.1% for Cu and 2.3% for Zn. Following a rinse the salivary concentration of Cu and Zn decreased rapidly during the first 4 h, approaching prerinse levels.

The intention of the present experiment was to study the effects of a possible interaction between fluoride and chlorhexidine when both agents were incorporated in the same vehicle. The amount of fluoride extractable from dentrifrices containing 0.1% NaF and the fluoride ion activity were not reduced by the addition of 2% chlorhexidine digluconate. Less than 50% of the added chlorhexidine was available when the dentifrices were dissolved in deionized water. This was not affected by the presence of fluoride. The in vitro antibacterial activity of the chlorhexidine-containing dentifrices was not reduced by the addition of fluoride. Approximately 40% of the chlorhexidine was retained in the human oral cavity after brushing for 1 min with both the chlorhexidine- and the chlorhexidine/fluoride-containing dentifrice. Thus the binding of chlorhexidine to vehicle ingredients when dissolved in water is probably too weak to affect the retention in the mouth.