In-Vitro Evaluation of Oral Irritation Potential of Three Whitening Dentifrices

Method: Products: Products: Surfactant-free dentifrice (REMBRANDT^® GENTLE WHITE), pyrophosphate and cocamidopropyl betaine-containing dentifrice (REMBRANDT^® INTENSE STAIN^®) and pyrophosphate and sodium lauryl sulfate-containing dentifrice (Crest^® 3D White). Each product was exposed to duplicate tissues at four different exposure times. The tissue viability was determined by the enzymatic reduction of MTT (3[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide). The toxicity of each product was evaluated on the basis of the relative tissue viability versus exposure time. The duration of exposure resulting in a 50% decrease in MTT conversion in the product-treated EpiOral™ tissues was determined (ET₅₀). Longer ET₅₀ values indicate reduced irritation potential.

Result: 

Conclusion: The data showed that the ET₅₀ values for both REMBRANDT^® dentifrices were longer compared to Crest^® 3D White dentifrice, thus indicating their reduced irritation potential as assessed by exposure to the in-vitro model and testing platform used in our study.   Both surfactant-containing dentifrices (REMBRANDT^® INTENSE STAIN^® and Crest^® 3D White) show increased irritation potential compared to the surfactant-free dentifrice (REMBRANDT^® GENTLE WHITE), however the irritation potential is reduced for the dentifrice containing cocamidopropyl betaine as a surfactant instead of sodium lauryl sulfate, which is a known irritant.  These results showed that the in vitro testing method used is a reliable pre-screening tool for the assessment of oral irritation potential of dentifrices.