This research is orientated to find an effective way to kill oral microorganisms that cause periodontitis and gingivitis with no problems of resistance, as it happens when we use antibiotics. The efficacy of this low power laser has been demonstrated in numerous fields in medicine and have been use it for years. The application of the photodynamic therapy is easy since we only have to fill the periodontal pocket with the photosensitive agent and apply the low power laser in that area. The photosensitive agent stain the bacteria immediately and the laser disrupts its membrane by a free-radical reaction. Improving the health status of the patients in a few weeks after treatment.