Allan Deutsch
FIGURE 1: Diagram from the
Endex apex locator instruction booklet.
FIGURE 2: Long by 0.5
to 1.0 mm.
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 ITHIN
the last few years, several clinical research articles have been published
that sort of upset the apple cart. Among the many articles
published recently on this topic are Success evaluation of 2,000 endodontically
treated teeth, by Imura N, Kato AS, Zaia AA, Gomes C, Ferraz CR, Teixeira
FB, Souza-Filho F (J Endodont 2001; 27(3)[Abstract No. PR11]:234) and Determining
the Optimal Obturation Length: A Meta-Analysis of Literature, by Schaeffer
MA, White RR, and Walton RE (J Endodon, 2005; 31:271). In both articles
the conclusions were the same. That is, the chances for a successful outcome
were higher in teeth that were filled “short” of the apex. The Schaeffer
paper, which did a meta-analysis of all the other research papers reported
on this topic, concluded: “The meta-analysis indicated that a better success
rate is achieved when treatment includes obturation short of the apex.”
So what does this mean? My interpretation
is that they are talking about the radiographic apex when they say “apex.”
Figure 1 is an excellent diagram taken from the Endex apex locator instruction
booklet.
It has been reported many times in the endo
literature that if we fill to the radiographic apex we will be long by
0.5 to 1.0 mm more than 50 percent of the time. To see what that
looks like see Figure 2.
Having that GP sticking into the ligament or
bone does not help healing. In fact, in a certain percentage of cases
it will retard healing and promote chronic irritation and inflammation,
and the patient will definitely let you know this.
Figure 3 shows us a case in which all three
canals are obturated just slightly long. On radiograph they may all look
very good; however, the odds are high that this case will not heal well,
and the patient may be symptomatic for months—and possibly longer.
Therefore, we want to fill anywhere between
the apical constriction and the anatomical apex—not the radiographic apex.
(See Figure 1.) This means that on radiograph at least 50 percent
of our cases will look short.
Figure 4 shows a well-placed gutta percha and
cement filling. It is approximately 0.5 to 1.0 mm short of the radiographic
apex, and it does not stick into where the PDL and bone would be.
This will heal well and become asymptomatic quickly. Figure 5 shows
a similar filling; however, in this case the anatomic apex and radiographic
apex are very close together.
Remember: a little short is better and more
conducive to a successful root canal procedure.
November - December 2006
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FIGURE 3: All three canals
are obturated just slightly long.
FIGURE 4: A well placed gutta
percha and cement filling.
FIGURE 5: The anatomic apex
and radiographic apex are very close together.
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