Tales from the Chamber
The Blunderbuss Apex, Déjà Vu!

Doug Kase
 
 

N THE WORDS of Andy Rooney, “Did you ever wonder what a dentist meant when he said ‘blunderbuss’?” Could it be a mass transit vehicle that drops everyone off at the wrong place? Or maybe it’s another clever advertising campaign by Volkswagen, you know, like Farfegnugen. They’re funny words, but does anyone care what they really mean? For an endodontist, a blunderbuss apex represents quite a challenge. It can present itself associated with a corresponding extra-wide canal, as in the case of a tooth that underwent trauma at a very young age while the tooth was still undergoing root formation and apical closure. Or, it can present itself as a resorbed apex associated with a chronic infection and resulting periapical radiolucency or due to an internal resorptive event triggered for example by some kind of trauma. Whatever the cause, creating an apical stop and subsequently an apical seal after appropriate instrumentation in a blunderbuss can be a challenging procedure for even the well-seasoned endodontist.
    Okay, so now you have a canal and apex that look like the Lincoln Tunnel! The radiograph shows a canal that is clearly wider than any instrument in your armamentarium, and clearly a number 140 file will pass readily through the apex. Well, as luck—or bad luck, depending on your perspective—had it, such a patient wandered right through my door. A 10-year-old child had such a tooth (Figure 1). At the age of six, he had suffered an impact trauma to his maxillary right central incisor, obviously before apical closure, and for the next three years his general dentist had observed the tooth for symptoms. His history was unclear on the subject of any clinical testing, such as vitality, that might have been performed; at that age and degree of root formation testing would not have been reliable; however, the end result was a periapical radiolucency and several bouts of discomfort and continued apical tenderness on palpation over the apex from the buccal.

Figure 1	Figure 2

    So, what should we do, and how should we treat? Apexification is not the treatment of choice due to the lack of an intact periapical PDL and a lack of vitality. It might have been a treatment choice at the very early stages of this event, but that time has passed. Certainly one might think that instrumentation, obturation, and a quick apicoectomy might be the sure-fire way to ensure an apical seal, but in the words of one of our favorite small green aliens named Yoda, “No, there is another!” Perhaps if there were some way to create a biocompatible apical seal without driving it out into the apical bone, we might be able to avoid a surgical intervention on our young patient; a surgical intervention was at the bottom of my wish list, and I’m sure that it was at the bottom of his as well!
    After I had discussed an appropriate informed-consent agreement with the patient’s mother (for all us dental-legal enthusiasts) and she had signd it, I gained access and measured the blunderbuss canal with an apex locater, confirming by radiograph (Figure 2). The canal was then instrumented with the widest instrument we had, which was a number 140. Rotary instrumentation consisted of a number 6 Peeso reamer and copious irrigation with sodium hypochlorite. Obviously, to some degree I threw the logic of the SafeSiders® technique out the window. It just didn’t apply in this case. After scraping the wall to the best of my ability in combination with EDTA and ultimately chlorhexidine irrigation, my thoughts wandered to “How the hell am I going to plug this thing?”

Figure 3	Figure 4

    Seven years ago, which brings us back to our title, I wrote an article about using MTA as a plug against which we could pack gutta percha. We all now know the miracles of MTA and perforation repair. It is also a wonderful matrix to create an apical seal as long as you can create a stop that prevents you from pushing the MTA out of the apex deep into the bone. In the case that I have described here, I used small plugs of Collicote pushed through the blunderbuss apex with a 9-11 plugger into the boney defect until I reached an apical stop that matched my apex locater measurement (Figure 3). Collicote is a resorbable collagen matrix against which I was able to pack a 3 mm plug of MTA, thus preventing its overfill into the boney crypt (Figure 4). As an alternative to using Collicote, BoneGen (see my articles “Product Review: BoneGen” and “BoneGen Part Deux”) is also a suitable material to pack beyond the apex into the bone. The rest of the canal was flooded with EZ-Fill® epoxy resin cement, and gutta percha was packed against the MTA (Figure 5). The tooth access was sealed with composite (Figure 6). Our young patient was followed up and had no postoperative symptoms and all his pre-operative symptoms had disappeared. The same can be said for his three-month follow-up.

Figure 5	Figure 6

    The next case comes from the other end of the age spectrum. This patient began every conversation with, “Doc, I’m 85 years old. The tooth will live longer than I will!” This 85-year-young patient presented with a chronic fistula and resorbed apex on tooth number 30 due to a long-term non-vital situation (Figure 7). After a Hail Mary consent, access, measurement (Figure 8), and some instrumentation, I was not able to get an apical stop at the distal apex due to extreme resorption and a blunderbuss apical opening.

Figure 7	Figure 8

    I thought, “Hey, let’s try that MTA trick on this canal and see what happens.” Again using Collicote as an apical barrier, I was able to plug MTA against it to seal the apex (Figure 9). Gutta percha was packed on top of the MTA with EZ-Fill cement, and the mesial canals were filled conventionally. Two weeks later he returned without any postoperative symptoms, and his fistula had closed (Figure 10). He was off with his wife to Costa Rica without postoperative symptoms and with no sign of infection.

Figure 9	Figure 10

    So, in retrospect, if you really think about it you will realize that being able to create an apical barrier against which you can plug an apical seal of MTA is basically the same thing that we do when we perform an apicoectomy using MTA as a retrograde material, except that in the case of the blunderbuss we are sealing from inside the canal without the surgical procedure. It’s a win-win situation for everyone!