Clinical Effect of Dentifrice Containing Zinc Citrate on Odor-producing Microorganisms

Research suggests that the tongue plays an important role in the production of oral malodor. Anaerobic organisms residing on the tongue contributes to halitosis and eliminates the odor-producing tongue flora would reduces bad breath.

Objectives: To exam the effects of a 1% Zinc Citrate containing dentifrice, after 12 hours overnight post-treatment, on tongue total bacteria and hydrogen sulfide (H2S) producing bacteria which implicated in halitosis.

Methods: A crossover design study contained 22 adults. Subjects completed a 1-week washout with a commercially available fluoride dentifrice and refrained from oral hygiene in the morning of baseline sample collection. Total and anaerobic bacteria were enumerated separately from baseline samples of tongue coating. For the next 7 days, subjects brushed twice daily with a randomly assigned dentifrice. Subjects arrived on day 8^th prior to oral hygiene and samples were collected for post-treatment microbial analysis. The procedure was repeated to complete the crossover design. Microbial counts from all phases of the study were log₁₀ transformed for statistical analyses.

Results: At overnight post-brushing, the use of the Zinc Citrate dentifrice resulted in a 30% and 23% reduction of total and odorigenic bacteria on tongue coating, respectively, compared with the fluoride dentifrice.

Conclusions: Brushing with dentifrice containing Zinc Citrate was effective in reducing VSC-producing and total bacteria present in the tongue coating. The study results indicated that the dentifrice with Zinc Citrate could effectively control odor-producing microorganisms to provide fresh breath benefit.