Working Length Deter

7/28/2019 Working Length Deter

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WORKING LENGTH DETERMUNATION

WITH RADIOGRAPH ENDODONTICS

For radiographic length determination, we rely upon our files and

radiographs. For a quick review of terms, the radiographic apex is wherethe apex appears on the film. The anatomic apex is where the apical

foramen is positioned, which may or may not be at the most apical part of the root. When using radiographs to determine the length of the root, it is

recommended that we estimate the length of the root from 0.5mm-1.0mm

from the radiographic apex.

2009

SHAWFEKAR

INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA

3/20/2009



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WORKING LENGTH DETERMUNATION WITH

RADIOGRAPH

Apex locators have become commonplace in the clinical practice of endodontics. They haveshown remarkable accuracy and reliability. Part of the skill in using an apex locator is

understanding when the reading is reliable or not. There are certain conditions where an apexlocator may not give a reliable reading and traditional length determination using radiographs is

required.

For radiographic length determination, we rely upon our files and radiographs. For a quick review of terms, the radiographic apex is where the apex appears on the film. The anatomic apex

is where the apical foramen is positioned, which may or may not be at the most apical part of the

root. When using radiographs to determine the length of the root, it is recommended that weestimate the length of the root from 0.5mm-1.0mm from the radiographic apex.

The reason for this estimation goes back to the early 1970's.

Palmer, Weine & Healy 1971 showed that when teeth are filled to the radiographic apex, thegutta percha is extruded out of the canal 50% of the time.

Burch & Hulen 1972 found that the apical foramen deviated from the anatomic apex 78%-99%

of the time.

Because of these early length studies, it is recommended to estimate your length short by 0.5-1.0mm.

Here is an interesting case that demonstrates how filling to the radiographic apex may actually be

filling long.



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Here is a post operative film following RCT of #3. I think most people would assume that theobturation looks pretty good.

1 year recall looks good radiographically, however the patient continues to reports some

sensitivity.

After some of the extruded sealer has resorbed, its easier to see that there is a slight over fill.

Since the patient's symptom persist, the tooth is treated surgically



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Surgical exposure of the root apices shows the extruded gutta percha and sealer.

Simple apicoectomy removes the extruded gutta percha.

This case shows how easy it is to overfill a root canal. Length determination using apex locaters

as well as radiographs is an important skill for any clinician performing endodontic therapy.



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Working Length Deter

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