FS03.4Irritant dermatitis following tape stripping

The aim of the study was to compare the effects of a SLS toothpaste formulation with and without betaine on skin and oral mucosa using electrical bioimpedance (IMP). Two groups, in total 47 participants, were recruited. In the skin group (27 participants) four test sites on the volar forearms were used: SLS paste, SLS + betaine paste, betaine paste, and one unoccluded control site. In the oral group (20 participants) the same toothpaste formulations were used. The test substances were applied in 12 mm Finn chambers for 24 hours at randomised test sites on the skin, and in 18 mm Finn chambers for 15 minutes on the oral mucosa. Visual examination and readings with IMP were taken before application and 24 hours after removal of the chambers for the skin, and for the oral mucosa before and 15 minutes after exposure. Information was extracted from the impedance spectra using four indices based on magnitude and phase at 2 frequencies, emphasising different aspects of the impedance properties of the tissues. The SLS‐containing pastes showed for both skin and oral mucosa some positive visual grade 1 reactions. Significant changes were found for the impedance indices, and the reaction patterns of the indices differed between the skin and the oral mucosa. We conclude that very slight reactions of skin and oral mucosa are detected by IMP. Furthermore, betaine containing toothpaste does not irritate neither skin nor oral mucosa, but the effect together with SLS is insignificant.