ReviewThe Role of Apical Instrumentation in Root Canal Treatment: A Review of the Literature
Section snippets
The Apical Constriction
The apical constriction (cementodentinal junction or CEJ) has long been advocated as the terminal end of instrumentation and obturation (3., 4.). It is in theory the narrowest part of the canal and the location where the pulp ends and the periodontium begins. Ricucci (15) advocated instrumenting to the apical constriction because impingement outside this junction may delay wound healing or result in adverse effects on the outcome of endodontic therapy. Materials or medications extruded beyond
Instrumentation
Over the years, many ways have been advocated for the ideal mechanical preparation of root canal systems based in large part upon obturation philosophy. In 1932, Jasper (36) believed that gutta-percha could be easily extruded from the canal and, therefore, advocated a gradual taper to the root canal to accommodate silver points. Years later, grossly tapered preparations were advocated by Berg (37). The canals were enlarged to quite large sizes to accommodate large heated pluggers that were used
Microorganisms in Dentinal Tubules
Table 3 summaries the in vitro and in vivo studies evaluating bacterial infection in dentinal tubules. Sufficient evidence exists to demonstrate that instrumentation and irrigation (9., 10., 66., 67., 68.) of root canals does not always remove all of the microorganisms. Bacteria are able to penetrate dentinal tubules in vitro and in vivo. Deeply embedded bacteria are shielded from instrumentation and irrigation, making their removal or eradication difficult.
Conclusion
The ultimate goal of root canal instrumentation is to eradicate bacteria from the root canal system (108., 109., 110.). The ability to thoroughly clean and shape the anatomic complexities of the canal system is the primary determinant for endodontic success (4). Longitudinal studies have shown instrumentation to larger files sizes doesn’t contribute significantly to the enhanced statistical success for endodontic therapy. However, these studies are often retrospective or have other factors
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