Review
The Role of Apical Instrumentation in Root Canal Treatment: A Review of the Literature

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Abstract

The issue of final apical preparation size remains controversial despite considerable clinical and in vitro research. The astute clinician must be aware of this research before choosing any instrumentation system because the informed clinician’s decision must be guided by the best available evidenced-based information. This review article generated a Medline-based search strategy to disclose these studies and provides a critique and summary of the results.

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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