Debris fill the flutes of the instrument. An accurate analysis of the flutes may help the endodontist in deciding about the eternal dilemma: to stop the shaping or continue the shaping ?

During the shaping we can face different situations. An analysis of the flutes determines the choice of the endodontist that, obviously, has to be confirmed in the following phases of cone fit or paper point placement.

Fig. 1

White flutes:

Ideal preparation, the flutes are fill of "white" debris. This means that the instrument touched an wide area of the canal and the dentine is sound.

This is the ideal condition. In general we can stop the preparation because the instrument touches a high percentage of sound dentine.

Fig. 2

Black flutes:

Even if the instrument is full of debris, the color means that the instrument touches only dirty dentin or residual endodontic pastes like endomethasone, thus  the apical dentin is probably infected.

In this case it is advised to enlarge the taper until sound dentine can be seen on the instrument. This is mandatory for achieving the success.

Fig. 3

Visible Flutes:

This situation happens when the canal is much larger than the instrument.

In this case, if it is possible, it necessary to increase taper and diameter of the endodontic instrument.

In case of wide canals, even a big instrument doesn't keep contact whit the dentine and it is impossible to appreciate the quality of the dentine. In this case copious irrigation has to be done, preferably using ultrasonic activation of the irrigants, in order to remove the debris from the root canal walls.

Fig. 4

Pink flutes:

This happens in case of retreatments and it means that in the apical area the walls are still filled with gutta-percha.

Ultrasonic tips help the clinicians in these case to clean the area from the gutta-percha remnants.

Fig. 5

Red flutes:

The presence of bloody flutes indicates the presence of pulp tissue in the apical area.

Fig. 6

Clinical example:

We have to increase the taper or the diameter preparation or both to eliminate the pulp tissue. In the picture, the shaping was conducted  from 25.08 (full of blood); followed by 30.09 (partially full of blood); 40.06 (white debris).

In some cases, expecially with particulary infammed pulp, the presence of blood can origine from the periapical tissue. In these cases it is important to understand where the blood comes from, because in the last case increasing the diameter and taper might play a negative role in the fracture resistance of the tooth.

Fig. 7

Different flutes or different instruments may facilitate the vision of these debris.


The cause of the endodontic failure is the permanence of bacteria in the canals. Cleaning and shaping procedures act in synergy to eliminate bacteria.

The comprehension of the anatomy of the lasts millimiters of the endodontic space plays an important role for the success of the therapy.


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