A randomized cross-over short-term study on the short-term effects of a zinc-lactate containing mouthwash against oral malodour

Aim: This randomized controlled cross-over-design-study investigated short-term effects on oral malodour of a zinc-lactate-containing mouthwash. Materials and Methods: Sixteen subjects (18-65 years) with an organoleptic score (OLS) >= 2 were included. Following rinses were used: (A) a zinc-lactate-containing mouthwash (10 ml/30 s); (B) a zinc-lactate-containing mouthwash (15 ml/60 s); (C) a rinse without zinc-lactate (3 droplets/10 ml tap water/30 s) and (D) tap water (10 ml/30 s). Each formulation was evaluated by two blinded examiners comparing OLS and three volatile-sulphur-compounds (VSC; H2S (hydrogen sulphide), CH3SH (methyl mercaptan) and (CH3)(2)S (dimethyl sulphide)) before, 1 and 3 h after rinsing. Subject's perception was investigated with a visual-analogue-scale. Linear mixed models were used to compare all parameters simultaneously with respect to the four treatment groups with a significance level alpha < 0.05. Results: OLS was significantly reduced by A and B compared to C and D after 3 h (p < 0.006). The sum of the 3 VSCs as well as H2S alone were significantly reduced by rinses A and B after 1 and 3 h compared to rinses C and D(p < 0.05). Significant differences were found between the four rinses for 'Taste' (p = 0.003), for 'Change of mouth feeling' (p = 0.001), for 'Feeling of freshness' (p = 0.002) and for 'Effectiveness' (p = 0.002) in favour of A & B. Conclusion: A zinc-lactate-containing mouthwash reduced OLS and VSC over a period of 3 h with favourable patient reported outcomes.