A Cochrane review [withdrawn from publication] included 5 studies comparing mouthrinses with other preparations or with placebo, involving a total of 293 participants. Pooling of the results and meta-analysis was not feasible. Twice daily mouthrinsing for 2 weeks with 0.05% chlorhexidine + 0.05% cetylpyridinium chloride + 0.14% zinc lactate (1 study, n=40) significantly reduced the mean change of organoleptic scores from baseline compared to placebo (–1.13 on a scale from 0 to 5, standard deviation [SD] 1.1 vs. –0.2, SD 0.7; P < 0.005) and also caused a more significant reduction in the mean change in peak level of volatile sulphur compounds (VSC) (–120, SD 92 parts per billion [ppb] vs. 8, SD 145 ppb). Organoleptic scores of ≥ 3 which correspond to VSC levels in excess of 75 ppb are generally accepted as diagnostic indicators of halitosis. Cetylpyridinium chloride + essential oils + chlorine dioxide + zinc mouthrinse twice daily for 4 weeks (1 study, n=95) produced a reduction in mean organoleptic score of –0.41 from baseline vs. 0.16 with placebo. Halimeter assessed mean VSC readings were reduced by –77.87 ppb vs. –36.77, respectively.The chlorhexidine cetylpyridinium chloride zinc lactate mouthrinse showed significantly more tongue (P < 0.001) and tooth (P < 0.002) staining compared to placebo.
Comment: The quality of evidence is downgraded by imprecise results (limited study size for each comparison), by limitations in study quality (inadequate or unclear allocation concealment, poor reporting of results) and by inconsistency (heterogeneity in interventions and outcomes).