title: A randomized double blind crossover placebo-controlled clinical trial to assess the effects of a mouthwash containing chlorine dioxide on oral malodor.
abstract: BACKGROUND
  Previous research has shown the oxidizing properties and microbiological efficacies of chlorine dioxide (ClO(2)), however, its clinical efficacies on oral malodor have been evaluated only with organoleptic measurements (OM) or sulphide monitors. No clinical studies have investigated the inhibitory effects of ClO(2) on volatile sulfur compounds (VSCs) using gas chromatography (GC). The aim of this study was to assess the inhibitory effects of a mouthwash containing ClO(2) on morning oral malodor using OM and GC.
  
  
  METHODS
  A randomized, double blind, crossover, placebo-controlled clinical trial was conducted among 15 healthy male volunteers, who were divided into 2 groups. In the first test phase, the group 1 subjects (N = 8) were instructed to rinse with the experimental mouthwash containing ClO(2), and those in group 2 (N = 7) to rinse with the placebo mouthwash without ClO(2). In the second test, phase after a one week washout period, each group used the opposite mouthwash.Oral malodor was evaluated before rinsing, right after rinsing and every 30 minutes up to 4 hours with OM, and concentrations of hydrogen sulfide (H2S), methyl mercaptan (CH(3)SH) and dimethyl sulfide ((CH3)2S), the main VSCs of human oral malodor, were evaluated with GC.
  
  
  RESULTS
  The baseline oral condition in the subjects in the 2 groups did not differ significantly. The mouthwash containing ClO(2) improved morning bad breath according to OM and reduced concentrations of H(2)S, CH(3)SH and (CH(3)(2)S according to GC up to 4 hours after rinsing. OM scores with ClO(2) were significantly lower than those without ClO(2) at all examination times. Significant reductions in the concentrations of the three kinds of VSCs measured by GC were also evident at all examination times. The concentrations of the three gases with ClO(2) were significantly lower than those without ClO(2) at most examination times.
  
  
  CONCLUSIONS
  In this explorative study, ClO(2) mouthwash was effective at reducing morning malodor for 4 hours when used by healthy subjects.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT00655772.
authors.affiliation: Department of Oral Health Promotion, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. shinada.ohp@tmd.ac.jp
authors.forename: Kayoko
authors.initials: K
authors.lastname: Shinada
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ueno
authors.forename: Chisato
authors.initials: C
authors.lastname: Konishi
authors.forename: Sachiko
authors.initials: S
authors.lastname: Takehara
authors.forename: Sayaka
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kawaguchi