Introduction: In order to accomplish periapical healing, a root canal system devoid of contaminated microorganisms is necessary. One of the main microorganisms linked to unsuccessful root canal therapy and persistent periodontitis has been identified as Enterococcus faecalis (ef). Various antimicrobial irrigation techniques and chemo-mechanical instruments have been proposed to eradicate bacteria from the diseased root canals. However, it is highly challenging to produce a sterile root canal system and entirely remove the diseased material due to the intricate internal architecture of the root canal. In order to clean the root canal, photoactivated disinfection (pad), often referred to as antimicrobial photodynamic therapy (apdt), is a relatively recent antimicrobial technique that combines a non-toxic photo-sensitizer (ps) or dye with a matching non-harmful light source or laser. When the fluid is injected into the root canals, it targets and tags bacteria specifically. Here, oxygen-releasing dyes may be photochemically activated by laser light. justification for using laser: the pad’s ability to specifically eradicate germs is its benefit. Moreover, it harms no adjacent tissues and has no effect on any other normal tissue. The restorations and gingiva are not stained. Furthermore, it doesn’t promote the emergence of any resistant species. root canal preparation is a need for using a laser in permanent teeth; iso file size 30 corresponds to the minimal amount of canal preparation needed for the laser tip to reach the apical region. photosensitizer/dyes: Methylene blue and tolonium chloride are two popular photosensitizers used in pads. These are phenothiazine family-related organic dyes. The appropriate laser wavelength, which is measured 1 mm short of the actual working length, is 650 nm, 660 nm, or 810 nm. This wavelength should be selected based on the affinity for a particular photosensitizer or dye working length. For example, if a canal’s working length is 19 mm, then 19-1 equals 18 mm. The length of the laser point that will enter the canal will be 18 mm. The chosen laser wavelength for laser root canal disinfection is 650nm, with a 300µm non-initiated tip, operating at 40mw and in continuous mode. procedures for disinfecting a root canal: under rubber dam isolation, each stage is carried out until the chemomechanical preparation (cmp), which is the same as in a traditional root canal system. pad comes first in the obturation process. To start, apply 15 ug/ml of toludine blue dye to the canals as a photosensitizer/dye. Second, wait. After removing any extra dye from the sulcus and the area around the teeth, wait two minutes to ensure that the dye has covered all of the walls and biofilms. application of a laser The following is the motion or laser usage technique: – the tip is removed from the canal at a speed of 2 mm per second; – the canal entrance is disinfected first, then the apex – rotate the tip circumferentially without making contact with the canal’s walls. – A cycle of laser irradiation lasts 60 seconds. – take a 20-second pause before continuing – the total number of cycles – 4 Remove the dye: Use sodium hypochlorite solution to cleanse the canal to get rid of all the dyes before obturation, after the conclusion of the laser irradiation. In summary, considering the intricate structure of root canals, the use of pads seems to be a viable approach to eliminating germs, even resistant strains like Enterococcus faecalis. References: 1. Dennis M. et al. An ex-vivo investigation of photoactivated disinfection (pad) of dental root canal system. Saudi Journal of Biosciences, Jan. 2016, 23(1): 122–127 2) In the December 2004 issue of Aust Endod J, Michael T. Lee discusses photo-activated disinfection of the root canal and a potential new use for lasers in endodontics. doi: 10.1111/j.1747-4477.2004.tb00417.x.