calcified canals

8/12/2019 Calcified Canals

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CALCIFIED CANALS

Calcification in the root canal, whether isolated or continuous,

can make treatment very difficult for the most skilled clinician.The use of chelating agents, magnification, fiberoptictransillumination, and pathfinding files can help the dentist find

and treat calcified canals.

Therefore, in calcified cases when the bur does not drop

easily into the chamber, the clinician should change to smallerdiameter

burs and, keeping the long axis in mind, direct thecutting action in apical-lingual version. If the canal orifice still

does not materialize after cutting in an apical direction, the

clinician should remove the bur, place it in the access cavity,and expose a radiograph; the resultant film will reveal the depth

of cutting and the angulation of cutting from mesial to distal.

Electronic apex locators are especially useful when treating

teeth with calcified pulp chambers, as a minute perforation can

be discerned before it is enlarged.

METHODS OF LOCATING CALCIFIED CANALS

Preoperative radiographs (Fig. 7-10) often appear to revealtotal, or nearly total, calcification of the main pulp chamber

and radicular canal spaces. Unfortunately, the spaces have adequate

room to allow passage of millions of microorganisms.The narrowing of these pulpal pathways is often caused by

chronic inflammatory processes such as caries, medications,

occlusal trauma, and aging.

Despite severe coronal calcification, the clinician must assumethat all canals exist and must be cleaned, shaped, and

filled to the canal terminus. It has been demonstrated that ca-

FIG. 7-10 Radiograph of a nonvital mandibular molar with

calcified canals.nals become less calcified as they approach the root apex.

There are many methods of locating these spaces (Figs. 7-11

to 7-29). It is recommended that the illustrated sequences be


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followed to achieve the most successful result.

In the event of inability to locate the canal orifice{s), the

prudent clinician will stop excavating dentin lest the toothstructure be weakened. Retrograde procedures become conservative

when compared with perforations or root fractures.

There is no rapid technique for dealing with calcified cases.Painstaking removal of small amounts of dentin has proven tobe the safest approach.

Text

Radiograph of a nonvital mandibular molar with

calcified canals.

FIG. 7-15 Radiograph of tooth in Figure 7-14 taken in 1989reveals severe calcification of the pulp chambers and periapical

and furcal radiolucencies.

MANAGEMENT


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FIG. 7-16 Mandibular first molar with a class I amalgam, calcifiedcanals, and periapical radiolucency. The assumption is

that a pulpal exposure has occurred, causing calcification and,ultimately, necrosis of the pulp tissue.

FIG. 7-17 Illustration showing excavation of amalgam and

base material. The cavity preparation should be extended towardthe assumed location of the pulp chamber. At this phase

of treatment the clinician must attempt to provide maximumvisibility of the roof of the main chamber. All caries, cements,

and discolored dentin should be removed.


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FIG. 7-18 Using a long-shank no. 4 or 6 round bur, the assumedlocation of the main pulp chamber is explored.

High-magnification eyeglasses, loupes, or the opcrating

microscope are helpful in searching for anatomic landmarks.Even apparently totally calcified main pulp chambers

leave a "tattoo," or a retained outline, in the dentin. The shape

of the pulp chamber in the mandibular first molar will be

roughly triangular or rectangular. The canal orifices are usually

found closest to the points of the triangle or the cornersof the rectangle. Other landmarks are the cusp tips (if they remain).

The orifices often lie directly beneath them.


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FIG. 7-19 The endodontic explorer, DG 16 (HU-Fricdy), isused to explore the region of the pulpal floor. It is as important

to the clinician doing endodontics as the periodontal probe

is to the dentist performing periodontal diagnosis. It is an examininginstrument and a chipping tool, often being called

upon to "flake away" calcified dentin. Reparative dentin is

slightly softer than normal dentin. A slight "tug back" in the

area of the canal orifice often signals the presence of a canal.

FIG. 7-21 As excavation proceeds apically, it is advisable to

check the proximity of the furcation. One technique is to place

warmed baseplate gutta-percha in the chamber floor with an


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amalgam plugger. An angled bitewing radiograph reveals the

amount of dentin remaining.

FIG. 7-22 Deeper excavation with no. 4 and 2 round burs,

following landmarks (removal of the rubber dam can often assist),

will usually produce a small orifice.

FIG. 7-24 Excavation extended apically in the direction of the

root apices.


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FIG. 7-23 As an adjunct to maximum visibility with magnification,

the fiberoptic light can be applied to the buccal or lingualaspect of the crown. Transillumination often reveals landmarks

otherwise invisible to the naked eye.

FIG. 7-25 At this point in the search, the clinician should beginto feel concern about the loss of important tooth structure,which could lead to vertical root fracture. The bur may be removed

from the handpiece and placed in the excavation site.

Packing cotton pellets around the shaft maintains the position

and angulation of the bur. The radiograph taken at right anglesthrough the tooth will reveal the depth and the angulation

of the search.


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FIG. 7-26 Further excavation apically with a long-shank no.2 round bur helps to locate the orifice. The endodontic explorer

is the first instrument to identify a pinpoint opening.

FIG. 7-27 At the first indication of a space, the smallest instrument

(a no. 06 or 08 file) should be introduced. Gentle

passive movement, both apical and rotational, often producessome penetration. A slight pull, signaling resistance, is usually

an indication that one has located the canal. Careful file

manipulation, frequent recapitulation, and canal lubricants(e.g., Calcinase, Glyoxide, R-C Prep) will assist in gaining


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access to the apical terminus. It is suggested that the access to

(he canal orifice be widened until the clinician can readily relocate

the orifice.

FIG. 7-28 A larger instrument is shown passing two curvatures

to the apex by locating one canal in a multicanal tooth.It is usually possible to locate the second, third, or fourth canal

once the first one has been located.

FIG. 7-29 Final canal obturation and restoration revealing anatomic


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complexities. This drawing appeared on the cover of

the fifth edition ofPathways of the Pulp. (The simulations of

the prepared and filled canals are courtesy of Dr. Clifford Ruddle.)

calcified canals

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