By Martin Goldstein, DMD
Wolcott, CT The title of this informal piece may be somewhat misleading, because I’m not going to write about post placement techniques. There’s no post-core design here either. And if you expect a discussion concerning which type of post is “best”, you’ll be disappointed.
In fact, I’m going to propose that many patients currently receiving endodontic treatment for post-retained build-ups would be better served if their dentist simply forgot the post.
Yes, I continue to use posts in my practice but with much less frequency. In some build-ups, many anteriors for example, there isn’t enough bonding surface to retain a core, so elective endodontics and a post may be the only way to go. And if a non-retentive tooth requires endo anyway, I often include a post in the core design.
However, if a broken down tooth is still vital and asymptomatic, I now think long and hard before prescribing elective endodontics simply to allow post retention. Because there’s a cost to elective RCT. I’m not referring to the extra $1000 it adds to the bill or the additional appointments. I’m talking about the increased chance of root-fracture, apical pathology and perio-endo lesions stemming from the occasional misguided post placement itself.
By the way, this is not a research-based paper, so don’t send me lab studies “proving” I’m crazy. This is an experienced-based paper based on my personal observations.
In the following paragraphs I’ll share my experience using a self-etch bonding agent (Brush&Bond) for post-free retention of core build-ups - even in situations where I once thought endodontic treatment, followed by a post and core (EPC) was mandatory. (EPC= Endo, Post and Core)
To illustrate my point, I’m going to show you the specific case that inspired me to write this article. As you’ll see, esthetically it doesn’t qualify for “best in show.” But three things make this particular case worthy of consideration -
n Most of the abutments were seriously broken down, offering little or no mechanical retention –
n A bonding agent alone (rather than a post) retained the cores -
n the core/dentin bond was severely challenged by two years of repeated bridge removal and several impressions.
Meet Janice ... Janice presented in the Spring of 2004 after having been referred to me by my associate. She exhibited a preexisting set of fixed maxillary bridges. Or rather one was fixed. The other had morphed into an RPD.
Janice had been on several medications that reduced salivary flow, which set the stage for an increase in carious activity (figs 1&2). The left maxillary bridge (9-12) was quickly running out of supporting tooth structure. Surprisingly, the lower arch was in much better shape. There were caries, but it lent itself to routine restoration.
After a thorough exam, Janice and I discussed her options, including the possibility of a maxillary full denture. We decided to try to save her remaining teeth. This would involve replacing her existing bridgework and adding an implant abutment or two for better support.
We’ve all seen teeth like Janice’s. Though they exhibit advanced caries, they’re still vital and totally asymptomatic. The X-rays show receded pulps. After caries elimination, we may be left with just a 1-2 mm stump of highly calcified dentin. Obviously, we have to crown these stumps, and we’ve been taught that proper crown retention requires a post-retained core. Since these are vital teeth, the posts will necessitate endodontic treatment.
Over the past 5 years, as I’ve gained faith in my adhesive techniques and materials, I’ve found myself using fewer and fewer endodontic posts. However, it wasn’t until I cemented Janice’s definitive bridge that I really sat down and re-thought my philosophy of post-retention. Fact is, when I began this case I fully expected to use the EPC approach on the majority of the teeth involved. But rather than start with the endo I elected to stabilize the arch with respect to total caries control, functionality, and appearance. There would be plenty of time to treat needy abutments during Phase II treatment as periodontal and implant treatment was progressing.
For long-term temporization, I often prefer the durability of a lab-fabricated provisional bridge. However, in a case like this, where I’m removing preexisting bridgework, I don’t know what I’ll discover under the old crowns. I might not even know the precise location of the abutments. Making the preps fit into a pre-made lab-fabricated provisional bridge can be an exercise in frustration. Sometimes the result is over-prepped teeth. So I decided to use two temps. A direct temp would be inserted initially. This would be replaced a month or so later by a lab-fabricated provisional. That way the lab could use an impression of the actual build-ups for fabrication of the lab processed provisional.
That said, before the initial operative appointment, I sent Janice’s impressions with both bridges in place to Smile-Vision* for a case mockup and fabrication of a hard/soft vinyl matrix former for direct temporization based upon that same mock-up. The initial operative appointment - When I removed the remaining bridge, what I discovered was worse than I’d imagined (Fig 3).
Tooth #3 was hopeless due to extensive root caries, not visible in the photo. #5’s coronal aspect had gone MIA. Teeth #7,8 and 9 demonstrated advanced circumferential caries.
But #10 took the prize. Instead of a crown preparation, strange alien-like tentacles emanated from the root. You guessed it, gutta percha!
#12 didn’t appear much better than #5.
The lone star was #13, which for some untold reason was caries free.
After caries removal there wasn’t much tooth structure left (fig 4). The serviceable abutments included #5,7,8,9,12 and 13. Except for 8,9 and 13, these were utterly non-retentive. About all you could say for them was that the root structure was sound and there were no frank pulpal exposures. Clearly they’d need a lot of help from the build-ups before they could retain a bridge.
For the past four years I’ve used Brush&Bond (and for a year or two before that, Touch&Bond) to bond all my cores. Brush&Bond consists of a liquid and a special MicroBrush that’s impregnated with polymerization enhancers. According to Parkell, there’s enough chemistry in the brush to activate three drops of liquid. So we expressed 3 drops of Brush&Bond liquid into a dappen dish and used a production line approach. I brushed it onto all six teeth (Fig 5). After it sat on the teeth for 20 seconds, I dried them with my air syringe, and sequentially cured each tooth for 5-10 seconds. The entire bonding procedure for all the preps took perhaps 4 minutes start to finish.
Note: Be sure to confirm with the manufacture of your bonding agent that it is compatible with dual- or self-cure core material. Most self-etch bonding agents, as well as most single-bottle total-etch systems are intended primarily for light-cure restoratives.
Brush&Bond and Touch&Bond are the exceptions, due in part to the polymerization-enhancers incorporated in the applicator brush and sponge (respectively). Absolute Dentin† core material was expressed onto the teeth directly from the automix cartridge (fig 6) and the surface was light-cured to allow immediate preparation (fig 7).
After prepping the cores with my highspeed, we took a silicone, Triple Tray impression and a separate bite registration to send to the laboratory†† for fabrication of the long-term provisional bridge. Premier’s ALFA trays are excellent for this purpose.
I then lubricated the cores with glycerin to prevent lock-on, and fabricated the initial temporary bridge. After confirming the fit of the Smile-Vision template (fig 8), the direct temp was fabricated and cemented in the mouth (Fig 8,9,11).
Janice was scheduled for periodontal surgery following my initial session, so it was decided to let the periodontist remove #3 and #10 at the time of surgery. (Yes, I did trim off the gutta percha tentacles before placing the temporary.)
About a month after this appointment – during the periodontal phase – Janice returned for cementation of the long-term provisional bridge.
Okay, let’s review the salient facts after this initial treatment phase –
1.) Most of the preps offer little mechanical retention (to put it mildly).
2.) There are no posts. The cores are retained by bonding agent alone (Brush&Bond).
3.) And so far, the core/tooth bond has survived –
a. Immediate preparation
b. Removal of an impression
c. Intraoral fabrication of a direct temporary bridge
d. Removal of the direct temporary bridge for cementation of the lab-fabricated provisional bridge. Fast Forward – one year A year later Janice had completed the periodontal phase, which included extractions, a slight ridge augmentation where #10 was extracted, plus placement of an implant in the only site that appeared to provide enough bone to house one - the #4 site. None of the cores had dislodged, so she had escaped visits to the endodontist.
She returned to us for final restoration.
At this appointment the provisional bridge was again removed, the teeth were packed with string and an impression was taken for fabrication of her definitive bridge. (We used stiff, sticky Impregum in this instance, so considerable dislodging forces were applied to the abutments during impression removal; no pop-outs, thank you very much! Finally, the provisional bridge was recemented.
Following a lengthy interim, Janice reappeared for temporary cementation of her final prosthesis - a DaVinci Lab full-arch Captek bridge (fig 14).** When we removed the provisional bridge, we discovered some rather “put upon” tissue (fig 15). The bridge was cemented with provisional cement. In my opinion the teeth were far too white – but that’s exactly what the patient requested. In fact, she loved it. Fast Forward Again ... Six weeks later Janice returned for yet another test of our Brush&Bond-retained build-ups.
To get the Captek bridge off, we had to use an air-driven reverse mallet (J. Morita’s ATD crown-and-bridge remover)¡
This time the soft tissue looked much happier (fig 15), so after thoroughly cleaning the abutments, the bridge was permanently cemented with Kerr’s self-etching cement, Maxcem¡¡. This final cementation took place approximately two years after placement of the core build-ups. (Yes, I know the teeth are still too bright!) Food for thought…. I’ve been in the dental business long enough to know that some day, endo just might be necessary for one or two of those abutments. The preps dipped very close to the pulps. Janice knows this also.
But I’m pretty sure that if RCT ever is required, it won’t be because those cores didn’t hold.
During two years of treatment that adhesive bond has survived:
Immediate preparation and impressing
Three removals of the temporary bridge in my office
Countless temp removals by the periodontist during extraction, surgery, implant placement and post-operative monitoring
Removal of an Impregum impression
Removal of the provisionally-cemented definitive bridge (with a pneumatic hammer, no less!)
Plus two years of function In this article I’m talking specifically about avoiding elective RCT before post-placement.
My patients are told the potential outcomes ...both the good and the bad. And for the most part, they’re delighted at the prospect of avoiding root canal therapy - even when I caution them that it remains a possibility sometime in the future.
By avoiding trips to the endodontist, both chair-time and cost to the patient are substantially reduced. And in my practice, the results of post-free bonded cores have been exceptional. Think about your own experience. How many posts have you seen dislodge, fracture or loosen ... too often taking the teeth with them? We’ve all gotten the phone call stating ”My crown is loose.” We know what that means immediately.
Keep in mind, the story above is not an across-the-board condemnation of post retained cores … I still frequently use posts when the tooth is already RCT’d or requires endo for other reasons ... (at least for now.)
One final observation: Parkell tells me they don’t solicit endorsements. So consider this only another observation: Since I started using Touch&Bond about 5 years ago (followed by Brush&Bond about 4 years ago), core pop-outs during tooth preparation and impression-taking have totally vanished. And post-op sensitivity has been very infrequent.
Again, thank you very much! * Smile Vision, Inc. - www.smilevision.net
† Parkell - www.parkell.com
†† Glidewell Laboratories - www.glidewell-lab.com
¥ Captek - www.captek.com
** DaVinci Dental Studios - www.davincilab.com
¡ J. Morita - www.jmoritausa.com
¡¡ Kerr - www.kerrdental.com
About Dr. Goldstein
Dr. Martin Goldstein practices general dentistry in Wolcott, CT. He lectures and writes extensively concerning cosmetics and the integration of digital photography into cosmetic dentistry. A Contributing Editor for Dentistry Today, he has also authored numerous articles for the Compendium, CERP, and other dental publications.
He can be contacted at martyg924@cox.net
For a summary of Dr. Martin Goldstein's upcoming lectures and courses, go to
http://www.drgoldsteinspeaks.com
|
Fig 1: Janice when she presented.
Fig 2: One of her bridges was serving as an RPD.
Fig 3 and 3a: Here’s what I discovered after removing the other bridge. Take a closer look at #12 (right).
Fig 4: Teeth #3 and #10 were hopeless. And after removing the caries from the other abutments there wasn’t much collective clinical crown remaining. Nevertheless, the planned abutments were still vital.
Fig 5: So I applied Brush&Bond to all the teeth ...
Fig 6: and expressed Absolute Dentin core material.
Fig 7: As soon as the resin had cured, I prepped the cores. Remember: No posts. No pins. Just Brush&Bond.
Figs 8-11: After taking the impression for a lab-fabricated long-term provisional, we made a direct temp using a template from Smile-Vision.
Fig 9: Provisional bridge - out of the template.
Fig 10: After trimming and glazing.
Fig 11: Provisional bridge temporarily cemented in the mouth. A month later this bridge was replaced with a lab-fabricated provisional.
Fig 12: When the patient returned from the periodontist a year later, we took a nice sticky Impregum impression.
Fig 13: When she returned for cementation of her Captek bridge and we removed the temp, the tissue looked pretty angry ...
Fig 14: so we provisionally-cemented the bridge and sent her home.
Fig 15: When she returned we needed a pneumatic hammer to remove the bridge. But this time the tissue looked much better.
Fig 16 & 17: So after 2 years we finally cemented the permanent bridge.
Fig 17: From the occlusal
Fig 18: Forget that it’s way too bright, and consider what those cores have endured.
|
