The effect of toothpaste on the propensity of chlorhexidine and cetyl pyridinium chloride to produce staining in vitro: a possible predictor of inactivation.
OBJECTIVE
Cationic antiseptics such as chlorhexidine (CHX) and cetyl pyridinium chloride (CPC) interact with dietary chromogens to produce extrinsic stain, and this can be used as a measure of activity of products. The aim of these studies in vitro was to determine if toothpaste influenced the tea staining effects of CHX and CPC as a predictor of action in vivo.


METHODS
Clear acrylic specimens were soaked in pooled human saliva followed by sequential 2-min soaks in pairs of agents, namely 0.05% CHX, 0.05% CPC, 0.2% CHX, water (W) and toothpaste slurry (TP). The combinations were; TP/CHX, CHX/TP, TP/CPC, CPC/TP, W/CHX, CHX/W, W/CPC, CPC/W, TP/W, W/TP, W/W. These treatments were followed by a 60 min soak in tea. Optical density readings were taken at baseline and after each of 8 cycles.


RESULTS
In the separate CHX and CPC studies by comparison with W/CHX, TP/0.05% CHX had little effect on staining, but TP/0.2% CHX showed a reduction in staining of 18%. 0.05% CHX/TP reduced staining by >40%, and 0.2% CHX by >78%. TP/CPC reduced staining by >26% and CPC/TP by 80%. Water after 0.2% CHX, 0.05% CHX and CPC reduced staining by 18%, 13% and 17% respectively. Little staining was seen with TP and W combinations. The data for CHX are in agreement with a study in vivo except TP followed by CHX reduced the activity of CHX.


CONCLUSIONS
Toothpaste appears to adversely affect the activity of CHX and CPC particularly if used immediately after the antiseptics. The data further supports the concept of separating the use of antiseptics until sometime after the use of toothpaste, and the idea of developing mouthwash friendly toothpastes.
Sheen
S
S
Division of Restorative Dentistry, Dental School, Bristol, UK.
Owens
J
J
Addy
M
M
D000180:Acrylic Resins; D000704:Analysis of Variance; D000891:Anti-Infective Agents, Local / Q000037:antagonists & inhibitors*; D002594:Cetylpyridinium / Q000037:antagonists & inhibitors*; D002710:Chlorhexidine / Q000037:antagonists & inhibitors*; D003802:Dentifrices / Q000493:pharmacokinetics; D004336:Drug Antagonism; D018565:Food-Drug Interactions; D006801:Humans; D009067:Mouthwashes / Q000494:pharmacology*; D012824:Silicic Acid; D012822:Silicon Dioxide; D012969:Sodium Fluoride; D013053:Spectrophotometry; D013662:Tea / Q000009:adverse effects; D014075:Tooth Discoloration / Q000209:etiology; D014100:Toothpastes / Q000494:pharmacology*
D000180:Acrylic Resins; D000891:Anti-Infective Agents, Local; D003802:Dentifrices; D009067:Mouthwashes; D013662:Tea; D014100:Toothpastes; C546060:hydrated silica gel-based toothpaste; D012824:Silicic Acid; D012822:Silicon Dioxide; D012969:Sodium Fluoride; D002594:Cetylpyridinium; D002710:Chlorhexidine