In-vitro Evaluation of a Novel Mouthwash Designed for Multiple Benefits

Mouthwashes have been shown to provide benefit to help control indications such as dental caries and periodontal diseases.  It has been reported that a combination of zinc chloride (ZnCl₂) and o-cymen-5-ol conferred a synergistic antimicrobial and anti-inflammatory mode of action.  A novel sodium fluoride mouthwash formulation was designed, incorporating zinc and o-cymen-5-ol with and without gellan gum as a thickening polymer.

Objectives:

The purpose of this study was to assess in vitro anti-microbial, anti-inflammatory and enamel fluoride uptake (EFU) efficacy of experimental mouthwash formulations using established test methods.

Methods:

Both water-thin and thickened formulations were evaluated in minimum inhibitory concentration (MIC) and kill time (modified EN1276) assays against S.mutans to evaluate potential anti-microbial activities. The water-thin experimental mouthwash (EM) was tested for its anti-inflammatory activity using EpiGingival^TM tissue.  The tissues were topically treated with mouthwash for 3 x 1min over 8 hours prior to challenge with P.gingivalis lipopolysaccharide (PG-LPS). The culturing media was collected 24 hours later and Prostaglandin E₂ (PGE₂) was measured.  EFU from the thickened formulation was measured using artificial carious bovine enamel lesions by a modified FDA test method #40.

Results:

The MIC of water-thin formulation was 1:512 against S.mutans and 1:1024 for thickened formulation.  In the kill time assay, both formulations showed 3 log reduction at 30 second and achieved maximum log reduction at 2 min.  Treatment with EM prevented PG-LPS mediated release of PGE₂ from EpiGingival^TM tissues. The EFU value from thickened formulation had no statistical difference compared to the fluoride solution control.

Conclusions:

The ZnCl₂ and o-cymen-5-ol containing mouthwash delivered strong anti-microbial, anti-inflammatory and enamel fluoride uptake activities in vitro. Addition of gellan gum had no impact on the performances of the formulation in our test models.