[Effect of irradiation with dental polymerized lamps on human Langerhans cells: a study made on human skin transplanted to nude mice].

Light polymerized composite resin materials are now widely used in dentistry. Most resins are polymerized by light sources which have a powerful emission of visible light and a small emission in the ultraviolet light A spectrum (UV-A 320-400 mm). Possible eye damage, induced by such light, has been investigated, but the effects on the oral mucosa, which is directly exposed to the light, have been examined in only one animal study. Langerhans cells (LC) are dendritic non-epithelial cells which form a network within stratified epithelia. LC have features of macrophages, functions as antigen-presenting cells, and play an important role in the immune system associated with skin and oral mucosa. Pilot studies on human skin transplanted to nude mice showed that radiation with small therapeutic doses from a dental light curing unit (DLU) having only a small fraction of UV-light can reduce or deplete the OKT6 surface marker of LC in human epithelium. Further investigation of the photobiologic mechanisms involved spectral analyses of the emmission from the lamps and construction of a suitable light source for establishing an action spectrum for LC in the UV-A range. The action spectrum for LC in the UV-A range was obtained by exposing human skin, grafted to nude mice, to monochromatic light with a band pass of 5-10 nm. Criterion for threshold doses was total depletion of LC, visualized by staining with known LC-markers, monoclonal antibodies OKT6, DAKO-Vimentin, DAKO-HLA-DR and DAKO-S-100. The action spectrum for LC consisted of a biphasic curve, with a non-linear, strong wave-length dependency.(ABSTRACT TRUNCATED AT 250 WORDS)