Proceedings of SPIE

p. 75-81LLLT has been used successfully in biomedicine and some of the results are thought to be related to cell proliferation. The effects of LLLT on cell proliferation is debatable because different studies found either increase or decrease on proliferation of cell cultures. Cell culture is an excellent method to assess both effects and dose of treatment. The aim of this study was to assess the effect off 635 and 670nm laser irradiation of H.Ep.2 cells In Vitro using MTT. The cells were obtained from SCC of the larynx were routinely processed from defrost to the experimental condition. Twenty four hours after transplantation the cells were irradiated with doses ranging from 0.03 a O.6J/cm2 during seven days. The results showed that 635nm laser light does not stimulate significantly the proliferation of H.Ep.2 cells in doses ranging from O.04J/cm2 to O.488J/cm2. However 670nm laser irradiation resulted in an increased cell proliferation when compared to both control and 635nm irradiated cells. It is concluded that irradiation of H.Ep.2 cells with 670nm laser results in an increased cell proliferation; best observation of cell proliferation was found on 670nm laser irradiated cultures exposed from doses of O.075J1cm2; both dose and wavelengths are factors which may affect cell proliferation of H.Ep.2 cells; doses of 635nm laser light up to O.48J/cm2 did not interfere with H.Ep.2 cell proliferation; and that the MTT was effective on the detection ofH.Ep.2 cells proliferation on both irradiated and non-irradiated cell cultures