Restoratively speaking, as adult teeth progress through different stages of their life cycles (i.e., small filling, larger filling, inlay, onlay, crown, root canal treatment, post-core-crown replacement, etc.), they continue to lose integrity. At the end and after many years of hard work in a very harsh environment full of physical and chemical abuse, some are eventually lost. Among the many reasons cited in the literature for the extraction of endodontically-treated teeth, the most commonly reported are: large carious lesions, unrestorable teeth, followed by root fracture, periodontal disease and last of all endodontic disease.
A conscious effort towards more conservative restorative and endodontic procedures will significantly contribute to the survival and retention of our precious natural dentition. Therefore, one of the most important goals in endodontic treatment should be: a more conservative access openings and instrumentation sizes. No restorative material is capable of replacing the lost natural tooth structure.
P.S. Respect the teeth and please stop using Gates Glidden or large round burs!