Three Interesting Cases

Young Bui, D.D.S.
Three Interesting Cases

Young Bui

OLLOWING are three interesting cases that I would like to share with all of you.
The first case was a strip perforation of the distal root of tooth #19 on the furcation side that occurred when the post space was prepared (Figure 1). Normally, with a perforation this big, the tooth would be deemed hopeless. However, with the invention of the miracle cement MTA, this tooth still had a chance of success. The first step was to remove the long Flexi-Post® without damaging the root further. I created an access opening wide enough to expose the head of the post. Then I used a CPR1 ultrasonic tip to vibrate the post loose from the cement. Once loosened, the post could easily be unwound using the wrench that comes in the post kit. After the post was removed, I went in and instrumented the canal, removing any gutta percha left in the canal. You should not try to seal the perforation until the canal has been cleaned and shaped. The reason is that, once mixed, MTA is a wet putty. You cannot irrigate and clean the canal after the MTA has been applied because the material will be dissolved by the irrigant. Instead, you should apply the MTA when the canal is ready to be filled. Mix the MTA into a putty consistency on the dry side then place it into the chamber. Take a large gutta-percha point or x-coarse paper point and use it as a plugger to push the MTA down the canal. Next use the SafeSiders® 25/.08 NiTi file to spread the the MTA along the wall that has the perforation. Spreading the MTA in this way will help seal the perforation and create a tapered canal space to place the gutta percha in. Figure 2 shows the completed case with MTA extruded out along the length of the furcation wall. Figure 3 shows healing of the furcation and periapical area eight months later.

FIGURE 1: Strip perforation of the distal root of tooth #19.	FIGURE 2: The completed case with MTA extruded out along the length of the furcation wall.
FIGURE 3: Healing of the furcation and periapical area eight months later.

The cause of failure in the next case was missed canals. The patient presented to the office with pain and swelling over #14. The pre-op x-ray showed thinly filled buccal canals with a large area in the furcation (Figure 4). Access was made and the post was removed as in the case above. Next I used a #8 slow-speed round bur to clean the floor of decay and stain. This procedure allows you to have better lighting so that you can locate canals better. Most upper molar failure is caused by missing MB2. That—and more—was the case with this tooth. After I had cleaned and shaped all the old canals, I found not only the MB2 but also a second palatal canal. You can see five separate filled canals in Figure 5. The key to locating extra canals is to take a #2 round slow-speed and sweep along any groove you find in the floor of the tooth. This will expose any ditch along the groove. MB2 is there at least 70 percent of the time in first and second upper molars.

FIGURE 4: Pre-op x-ray showed thinly filled buccal canals with a large area in the furcation.

FIGURE 5: Showing five separate filled canals.

The last case is pretty much a straightforward root-canal case. The only interesting part of this case is the curvature of the mesial root and the lateral canal near the apex of the distal root (Figures 6 and 7). Upon encountering a curve like this one, the first thing that should come to your mind is to reduce the amount of curvature. By using a #2 Peeso reamer and leaning it against the outer wall, you will turn a C-curvature into a J-curvature. This will reduce the stress on your file or reamer. My suggestion is to use the SafeSiders reamers with the reciprocating handpiece. The SafeSiders reamer is flexible and less binding due to the flat side. This will allow you to instrument the canal without causing any distortion. The bi-directional spiral is a great instrument to apply cement with. The flutes on the spiral force the cement to converge on itself, creating a force that spreads the cement against the wall. This will disperse the cement into the lateral canal.

FIGURES 6 AND 7: Showing curvature of the mesial root and the lateral canal near the apex of the distal root.

January-March 2005

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