Further in vivo studies on the plaque-inhibiting effect of chlorhexidine and its binding mechanisms.
The aim of the present study was to investigate the relative importance of chemical groups in the oral cavity which bind chlorhexidine of clinical significance. This was performed by clinical experiments where a test panel of 11 individuals rinsed with chlorhexidine at pH 7, pH 5.5, and pH 3. Rinsing with 0.02 M EDTA was performed prior to the chlorhexidine rinse, because this procedure has been shown to enhance the antibacterial effect of chlorhexidine in vitro. However, pre-rinses with EDTA did not increase the clinical effect of chlorhexidine. Bacteriologic tests showed comparable antibacterial effect of chlorhexidine at pH 7 and pH 3. Mouthrinses of pH 7 and pH 5.5 had comparable plaque-inhibiting effects, whereas the effect of a rinse of pH 3 was not different from that of the placebo. This finding is interpreted to suggest that primary phosphate (pK about 2) is an important receptor site for chlorhexidine, whereas secondary phosphate (pK = 7.0) is of negligible importance. Previous studies have clearly shown that phosphate binds chlorhexidine. The lack of clinical effect at pH 3 is probably due to precipitation of salivary proteins by hydrogen ions, making primary phosphate groups unavailable for interaction with chlorhexidine.
Waaler
S M
SM
Department of Pedodontics and Caries Prophylaxis, Dental Faculty, University of Oslo, Norway.
D000328:Adult; D002710:Chlorhexidine / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D003773:Dental Plaque / Q000503:physiopathology / Q000517:prevention & control*; D004311:Double-Blind Method; D004492:Edetic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008875:Middle Aged; D009067:Mouthwashes; D010710:Phosphates / Q000378:metabolism; D010919:Placebos; D011955:Receptors, Drug / Q000378:metabolism; D013298:Streptococcus sanguis / Q000187:drug effects
D009067:Mouthwashes; D010710:Phosphates; D010919:Placebos; D011955:Receptors, Drug; D004492:Edetic Acid; D002710:Chlorhexidine