Background: Irritant contact dermatitis of the hands is very common in dental laboratory technicians due to frequent contact with various irritants. Barrier creams (HS) are often avoided because a tight grip of tools and small objects is necessary; furthermore dental objects must not be contaminated by HS. In this study the efficacy of HS applied during working hours was compared to skin care products (HP) applied only after work.
Method: 2 popular commercial HS (HS-1, HS-2) and 2 moisturizers containing urea and beeswax respectively (HP-1, HP-2) were evaluated in 5 laboratories by a total of 192 technicians. Every technician used one HS (several applications during working hours) and one HP applied at home at least once daily for 4 weeks each with a wash-out period of 2 weeks in between. The sequence HS-HP, HP-HS was randomized for every laboratory in two single blind cross over designs for both combinations (HS-1 with HP-1, HS-2 with HP-2). The technicians scored the products on a scale of efficacy (worse, none, good, very good). The skin condition was evaluated by a dermatologist at the beginning of the study, after 4, 6 and 10 weeks on a scale for erythema, infiltration, vesicles, fissures and scaling to produce a sum score. Furthermore, transepidermal water loss (TEWL) was measured on the back of the hand and on the ventral aspect of the forearm at the beginnung and the end of the 4 weeks application period. The quotient of these two parameters was used for statistical evaluation (covariance analysis).
Results: The assessment of either "good" or "very good" was as follows: HS-1 58%; HS-2 67%; HP-1 77%; HP-2 98%. Both HP, particularly HP-2, were judged superior to either HS. This was confirmed by the improvement of the skin condition (HS-1 35%; HS-2 44%; HP-1 55%; HP-2 56%). Statistical significance of the differences in TEWL data was clearly demonstrated: HP-1 better than HS-1 (p = 0.007); HP-2 better than HS-2 (p = 0.03). The acceptance of the products was high. The majority was willing to continue its usage after the study (68 %-89 %).
Conclusions: The results demonstrate that the use of after work moisturizers is highly beneficial and under the chosen study conditions even superior to barrier creams applied at work. This approach is more practical for many professions and may effectively reduce the frequency of irritant contact dermatitis.