Consider these observations:
These are but a few of the many documented cases of root tip endos that I’ve seen over the years in practice. The patients are all asymptomatic, albeit clearly not functional. We can see food, plaque, and caries sitting on the root filling. These roots have been infected for years. If we were to say that there was some sort of threshhold of bacteria that need to be removed to have a favorable endodontic outcome; these teeth would represent the maximum, most bacteria filled, most infected roots possible. And as such these teeth should have both clinical symptoms of pain and swelling as well as radiographic signs of endodontic pathosis. However, all of these patients are asymptomatic. And radiographic interpretation suggests they are typically free of apical findings. How could it be that the most infected roots have no radiographic findings? It must be something more than just the presence of bacteria or some degree of bacteria in the root of the tooth that defines endodontic pathosis.
Perhaps the lack of occlusion on these roots has something to do with it. If this is true, as the available evidence suggests, then occlusal function plays a role in “endodontic pathosis”. Such a supposition isn’t terribly surprising in that occlusal parafunction can lead to endodontic necrosis in the absence of caries. Furthermore, many of the signs and symptoms traditionally associated with infection related endodontic pathosis can be associated with occlusal parafunction even in the absence of infected roots or proximal caries. Thus, the myriad of endodontic conditions that present in clinical practice are not well explained by the apical periodontitis disease model and the relationship between radiographic findings and endodontic pathosis is not a direct one.