A non-staining chlorhexidine mouthwash? Probably not: a study in vitro

Tooth staining is a common side effect of chlorhexidine mouth rinses and caused by the interaction of the di-cationic antiseptic with dietary chromogens. A product is now available, which claims an anti-discolouration system (ADS) with one clinical study in support. This study in vitro aims to determine whether two ADS rinses do or do not bind dietary chromogens.

Optically clear acrylic specimens were cycled through human saliva (2 min), one of the three chlorhexidine rinses (two ADS and a positive control) (2 min) or water and then soaked in tea (60 min). After each cycle the optical density (OD) of specimens were read on a UV/visible spectrophotometer. The exit point was the cycle at which OD was >2.0.

All three rinses exceeded OD 2 at 11 cycles and there was no significant difference in staining for the ADS rinses compared with the positive control rinse.

Based on extensive literature for the correlation of this test in vitro with chlorhexidine anti-plaque activity and propensity to stain in vivo these ADS rinses will have the same anti-plaque efficacy and potential to cause stain as established chlorhexidine rinse products.