Mechanically, both conditions are treated in a rather similar manner, by "cleaning and shaping", using endodontic files and irrigation solutions. This mechanical process is aimed to thoroughly disinfect the root canal by removing all tissue remnants while enlarging the diameter of the root canal, to remove all canal irregularities that may harbor bacteria. During this process an inner layer of dentin has to be removed from all the surface of the root canal. A second goal of root canal treatment is to allow adequate sealing of the canal space by a root canal filling, in order to prevent future bacterial contamination. For teeth with inflamed vital pulps, once this stage is completed the root canal may be sealed. When necrotic infected root canals are involved, this stage greatly reduces the bacterial load in the canal but an additional stage of disinfection by medicaments, sealed in the canal until the next appointment, may be required.