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Q & A FotoSan®

Does light activated disinfection also work on anaerobic bacteria? YES, LAD works equally on aerobic and anaerobic bacteria. What the question probably really means, is whether anaerobic bacteria can be destroyed as the LAD process requires oxygen. The answer is YES. The anaerobic bacteria hide in a biofilm, but because of the scaling before the FotoSan treatment, the biofilm is disrupted. However more importantly the active oxygen (ROS)  destroys the polysaccharides in the biofilm. It’s cut into pieces exposing the bacteria. Remember also that the FotoSan Agent you inject into the pocket contains oxygen.
Does light activated disinfection work equally on Gram-pos and Gram-neg bacteria?  Yes, it works on both types. In the litterature it is mentioned that Gram-neg are more resistant to the treatment, which sounds  theoretically right, as they have an extra membrane. In practice, however, in a study at Bern university with FotoSan the results show that Gram-neg are much more sensitive to the LAD treatment than expected.
Why does the LAD not harm human cells? Toluidine blue does not bond to intact human cells.  The reactive oxygen specimens (ROS) created in the process, have an extremely short life time (nano seconds). Furthermore the ROS transport only a very short distance ( few microns) so the photosensitizer has to bond to the surface of the target to have an effect.
Why are only pathogen bacteria killed? Well, it is not the case. All bacteria are killed - at variable speed - however the “good” bacteria will get a head start in recolonizing the pocket. It is a  race between the good and bad bacteria, and the good will take over - after all they are so more abundant. 
Clinical data show that the  bacteriological effect after just one treatment is better in the period 6-12 weeks after, compared to the period 0-6 weeks after treatment.
What about dry socket. Does LAD work on that? There are no clinical studies published on this subject, however unpublished case reports show a positive result.
Can you treat directly on an open wound? And when bleeding? Yes, you can do that. Several dentists have noticed that there is a hemostatic effect of the treatment. That can be explained by the interaction between the reactive oxygen and blood proteins. Bleeding will however dilute the LAD effect somewhat.
Can I purchase the FotoSan Agent and use with another light?  In principle yes, if the other light has an emission spectrum with a maximum around 630 nm. However, if the light is not as powerful as the FotoSan light you will have to compensate by using longer treatment time. Remember that it is the emitted energy, i.e. output power x time that is important. So half the output power means double treatment time.
What about when the root canal is curved, does the light get all the way to apex? The canal is filled with fluid, so the canal itself will work as a light guide. To be sure to get enough light energy we recommend to give an extra 30 s if the tip does not goes approximately 2/3 into the canal.






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