• Oral malodor was evaluated at before rinsing, right after rinsing and follows up every 30 minutes till 4 hours with organoleptic measurements. [ Time Frame: 4 hours ] [ Designated as safety issue: Yes ]
  

• Oral malodor was evaluated at before rinsing, right after rinsing and follows up every 30 minutes till 4 hours with the concentrations of 3 kinds gases of human oral malodor analyzing with gas chromatography. [ Time Frame: 4 hours ] [ Designated as safety issue: Yes ]
  

Other: Chlorine Dioxide
Experimental mouthwash (ClO2 Fresh®): 0.16% sodium chlorite (NaClO2) with an efficacy of 0.1% chlorine dioxide (ClO2),Placebo mouthwash: glycerin, mint oil and distilled water, contents are almost the same as those in the experimental mouthwash except ClO2.

A randomized, double blind, crossover, placebo-controlled clinical trial was conducted among 15 healthy male volunteers, who were divided into 2 groups: experimental or control group. In the first test phase, the subjects in the experimental group were instructed to rinse with the mouthwash containing ClO2 and those in the control group with the placebo mouthwash without ClO2. In the second test phase after one week washout period, same procedure was conducted with the opposite mouthwashes. Oral malodor was evaluated at before rinsing, right after rinsing and follows up every 30 minutes till 4 hours with OM, and the concentrations of hydrogen sulfide (H2S), methyl mercaptan (CH3SH) and dimethyl sulfide ((CH3)2S) which are the main volatile sulfur compounds (VSCs) of human oral malodor were evaluated with　GC.