Page 12 - The Beauty and Sorrow in Endodontics (WL and C/S)

pathogens present in this area, one can only hope that an equilibrium between the host

and pathogen can be maintained throughout life.

3. Apical Constriction

The apical constriction is the narrowest part of the apical root canal, however, it is
unknown whether this refers to a particular point or area. There is a possibility that it

exists in a healthy, unaffected apex. However, if the apex has been resorbed or is still

developing, there is no apical constriction. In addition, the tactile sensation of feeling
the constriction is different for everyone, making it a difficult reference point to

impart to each dentist.

4. Apex

In dental anatomy, the apex is the most apical point of the root. Radiographically, it is
the point that is most protruded at the end of the root. As mentioned earlier, cementum

is not deposited evenly throughout the entire root structure and will continue to grow
throughout a person’s life. Under external pressure (eg. orthodontic treatment), the

cementum will be resorbed first, and will grow back as the tooth reaches a new

position. Therefore, the location of the apex can vary from time to time. It is
recommended that the ideal working length be 0.5-1.0mm short of the apex, which is

where the apical foramen is believed to be located. However, this is a statistical
average, which does not account for individuality of each root, and therefore, the apex

is not a recommended point of reference either.

The following represents important terminology and ideas in Schilderian
Endodontics:

A. To Radiographic Terminus (RT): Where a small file touches the PDL

During cleaning and obturation of the root canal, precise control of the working
length is imperative. The internal reference point when measuring working length is

the point where the file reaches the radiographic terminus (RT). On a radiograph, the

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