Page 19 - The Beauty and Sorrow in Endodontics (WL and C/S)

and shaping, the pre-formed gutta percha cones may need to be adjusted by reshaping

them to a taper that corresponds to the canal better, and then using them for comparison
with the master apical file and cone fit check. (Don't forget that Dr. Schilder was very

against the use of an endo ruler to determine working lengths).

As a matter of fact, the process of cone fitting should be fast and simple. If the

master cone still does not correspond to the lWL of the master apical file even after
adjustment, then chances are more shaping of the canal is required. It is prudent to keep

in mind that the lWL of the master apical file will change if additional shaping is
completed of the apical third of the canal, so new measurements and comparisons will

need to be made prior to the new cone fit try-in.

d. Cone fit check WL; cWL:

When a master cone that is comparable to the taper and size of the apical third of the
canal, it is importance to place the cone in the canal and check for tugback PRIOR to

comparing it with the master apical file and marking the lWL on the cone. Preliminary
markings on the cone can blur the objectiveness in determining tugback. Once the cone

fit radiograph confirms the placement of the cone, it is then taken out and disinfected in
sodium hypochlorite solution. The master cone should be placed to a depth 0.5-1mm

coronal to the canal exit to allow the warmed gutta percha and sealer to flow and fill in

the irregular apical foramina during warm vertical compaction, which show up as white-
in-white dots in the final obturation radiograph. (See “Warm Vertical Compaction

Technique” and “Summary of Schilderian Techniques” for tips on how to adjust the

master cone after cone fit try-in.)

e. Final WL; fWL:

A final radiograph showing the densely filled canals further conveys the success of the

operator’s hard work during cleaning and shaping. Often times the final obturation length
is what people focus on when examining the final obturation radiograph. However, given

the complex anatomy of the apex (as discussed earlier), it is very difficult to determine

where the actual canal exit is on a 2D radiograph. The only way to confirm that is

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