title: A new mouthrinse combining zinc and chlorhexidine in low concentrations provides superior efficacy against halitosis compared to existing formulations: a double-blind clinical study.
abstract: OBJECTIVE
  Volatile sulfur compounds (VSC), mainly derived from bacteria located in deep crypts at the back of the tongue and from periodontal pockets, are responsible for approximately 90% of halitosis (bad breath, malodor). The objective of this double blind clinical study was to assess the clinical efficacy of a new formulation for halitosis containing a combination of zinc (0.3% Zn) and chlorhexidine (0.025% CHX) in low concentrations. The new formulation was compared to some widely used and commercially available formulations containing various enzymes and antibacterial agents in a clinical setting under controlled conditions.
  
  
  METHODS
  Ten healthy volunteers participated in this study (5 female, 5 male, mean age: 46.6, range: 26-79). Each participant served as their own control, and neither the investigator nor the ten test subjects knew which formulation they were testing at any given time (double-blind design). Baseline H2S data were obtained by cysteine rinsing for 30 seconds, 90 seconds mouth closure, and gas chromatographic (GC) analysis of mouth air. On separate days, each participant then rinsed for 60 seconds with 10 ml of each of the eight various formulations. Cysteine rinses were repeated at 1 hour, 2 hours, and 3 hours, and GC measurements of oral H2S levels were again recorded.
  
  
  RESULTS
  The test rinse (0.3% Zn + 0.025% CHX) reduced the intraoral H2S levels to 0.16% of control (range: 0.01-0.54%) after 1 hour, 0.4% after 2 hours, and 0.75% after 3 hours, providing superior efficacy in reducing H2S compared to the other formulations tested (p < 0.05).
  
  
  CONCLUSIONS
  A combination of Zn and CHX in low concentrations seems to be the most efficient way to remove the VSC that causes bad breath at present. Studies are underway to further explore the extraordinary efficacy of this combination (close to 100%), suggesting a specific mode of action and a synergistic effect of these two components.
authors.affiliation: Dental Faculty, University of Oslo, Norway. p.s.thrane@odont.uio.no
authors.forename: Per Stanley
authors.initials: PS
authors.lastname: Thrane
authors.forename: Alix
authors.initials: A
authors.lastname: Young
authors.forename: Grazyna
authors.initials: G
authors.lastname: Jonski
authors.forename: Gunnar
authors.initials: G
authors.lastname: Rölla
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002710:Chlorhexidine / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006209:Halitosis / Q000188:drug therapy*; D006801:Humans; D006862:Hydrogen Sulfide / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009067:Mouthwashes / Q000737:chemistry / Q000627:therapeutic use*; D014131:Trace Elements / Q000627:therapeutic use*; D015032:Zinc / Q000627:therapeutic use*
chemical_list: D009067:Mouthwashes; D014131:Trace Elements; D015032:Zinc; D002710:Chlorhexidine; D006862:Hydrogen Sulfide