Objectives: To assess the comparative activity of mouthrinses containing cetylpyridinium chloride (CPC) and chlorhexidine using the propensity to cause extrinsic staining in vitro as the outcome variable.
Methods: Saliva-coated clear acrylic specimens were exposed to cyclical staining regimens of either CPC or chlorhexidine followed by tea. Water and 0.2% chlorhexidine were used as negative and positive controls respectively. Staining cycles were repeated until an optical density of > 2 was reached by one of the products.
Results: For CPC there was a highly significant difference in staining between the products. Two CPC products performed numerically little better than water. For the chlorhexidine products the 0.2% formulation produced the most staining although little more than the UK version of the 0.1% rinse. The French 0.1% rinse produced by the same manufacturer as the UK formulation showed markedly reduced staining potential although significantly greater than water.
Conclusion: This study, supported by previous in vitro and in vivo studies, indicates discrepancies in the availability of CPC and chlorhexidine in some mouthrinse products. Importantly, this may have an effect on the potential of some rinses to provide the expected plaque inhibitory activity.