May 1, 2005
by Richard Mounce, DDS
A discussion of the implications of obturating “short” of the anatomic apex of the root was initiated in Part I of this column last month (April, 2005). Its discussion concludes here.
As mentioned, the apical foramen is, on average, located 0.26-0.99mm from the anatomic root end apex (references available). While this anatomic average might be helpful in providing a general guideline, it is not of much help in determining the true working length of the actual case the clinician is treating. As it relates to the question, many canal systems have apical delta canals that ideally should be soaked in irrigation such as sodium hypochlorite long enough to dissolve out their contents to the extent clinically possible. It is axiomatic that files of any type, K or rotary cannot be reproducibly placed into lateral anatomy and hence their cleaning is dependent solely upon irrigation.
As one moves apically the variety and number of lateral canals and apical deltas becomes more complex and diverse. As a result, the greater the number of mm from the anatomic apex a given obturation, the greater the amount of lateral anatomy that remains unfilled especially if there are multiple foramina. In Figure 1, the actual root canal obturation may only be about 2mm short of the anatomic apex. The accumulation of dentin mud present was likely to have created an apical blockage and leave in actuality about 5-7mm of uncleaned and unfilled space in the apical third when the multiple foramina are considered. Often, these foramina are often only visualized upon obturation via warm techniques such as SystemB or the vertical compaction of warm gutta percha. It is important to realize that this can be avoided by
1) Precurving all hand files which are put into canals
2) Copious irrigation with sodium hypochlorite
3) Achievement of apical patency
4) Maintenance of apical patency via recapitulation
5) The clinician actively trying to feel for a tangible “pop” as the K file exits the minor constriction of the apical foramen
6) Use of EDTA in vital cases especially in the form of a gel to emulsify the pulp and hold it in suspension until its removal with sodium hypochlorite irrigation.
In short, the clinical implications of filling “short” are significant. The farther from the given anatomic apex the given root canal is completed, the greater the amount of uncleaned and unfilled space that is left in the root canal system leaving a potential source for future failure. I welcome your questions and feedback.
Dr. Mounce would like to thank Dr. Gary Carr, EIE2, PERF and the Digital Office Program for Endodontists for the image in Figure 1.
Photo credit: Dr. Carr, EIE II, PERF and the Digital Office Program for Endodontists.
I saw from X-ray at dentist office the endo didn’t go all the way down the root after procedure. There was too much ear pain during procedure. He paced it halfway on one root. In a lot of pain when I lie down. Now on both sides of jaw.
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