Osteonecrosis and Ischemia in the Alveolar Bones

At a recent seminar, Dr. Jerry Bouquot, the director of diagnostic services at University of Texas, Houston - School of Dentistry, and world reknown oral pathologist and specialist in bone pathology, discussed osteonecrosis of the alveolar bone and issues with ischemia in bone.

The recent issues with bisphosphonate induced osteonecrosis of the jaw bones and well known complications with osteoradionecrosis, demonstrate the severe complications that can occur with ischemia in bone. Dr. Bouquot shared some of his ideas regarding possible sources/causes of ischemia in bone.

The follow video clip highlights the differences between alveolar bone and regular skeletal bone. According to Dr. Bouquot, these differences make the alveolar bone more susceptible to ischemic bone pathology.

Finding Missed Canals Using Cone Beam Computed Tomography (CBCT)

We have had lots of discussion regarding the use of CBCT in endodontic diagnosis and treatment planning. CBCT is the future of endodontics. 3D imaging as an adjunct to 2D imaging is superior to 2D imaging alone. The ability to evaluate a tooth in a sagittal and axial plane (in additional to the traditional coronal view of standard radiographs) provides valuable information that will lead to the preservation of teeth by improved endodontic treatment, endodontic retreatment and endodontic surgery.

There will be many who think this statement is over the top. However, I would compare the advent of focus-field, high resolution CBCT to the introduction of the operating microscope in endodontics. While there was initial resistance to adoption of the microscope, and still some continued resistance by a few in our specialty, the microscope has undoubtedly improved the quality of endodontic care. CBCT is the same. There will be some who argue that they don't need it, however, it undoubtedly will improve the quality of endodontic care and help preserve teeth.

As an example of the benefits of CBCT in improving endodontic diagnostics and treatment, I present the follow 4 cases. Each case completed by a different endodontist. All of these clinicians are highly skilled endodontists using microscopes. However, in each case, canals were missed and the patient continued to have issues. They have different stories, but all ended up in our office for an evaluation or second opinion. I have included myself as one of these 4 endodontists. (One of the cases is my own)

CASE #1

#31 is the symptomatic tooth. Two canals have been filled to a good length.

CBCT slice of mesial root shows the two mesial canals join and exit at one apex.

This is another slice of mesial roots showing the buccal filling and the ML missed canal. The sagittal view tells us where to look when we retreat this tooth. Axial view also demonstrates the missed canal. Using these two views, when I retreat this tooth, I will know where to explore without perforating the root.

This particular endodontist refunded the patient and preferred that we retreat the tooth at our office.

CASE #2

This root canal was treated by another endodontist and then retreated after symptoms failed to resolve. She came to Superstition Springs Endodontics for a second opinion. The obturated roots look filled to an ideal length.

CBCT reveals a missed MB#2 canal. Blue outline shows an axial slice of the MB root. The pear-shaped root outline reveals the missed canal.

The sagittal view also shows the MB#1 canal is off center of the long axis of the root. A lesion into the sinus cavity is noted. Note the distinct MB lesion visible in the CBCT. I explained to the patient that it would be the other endodontist would likely retreat this tooth at no charge, but this patient has elected to retreat the tooth in our office.

CASE #3

This root canal done in 2007. Recently became symptomatic.

CBCT shows lesion on MB and DB with elevation of floor of sinus. This corresponds to chronic sinus issue patient has been dealing with.

Cross sectional slice (axial) through the MB root shows the missed MB#2 canal. The pear-shaped or figure-8 shape of the MB root reveals the missed MB#2 canal.

This sagittal view shows that the missed MB#2 canal is actually a separate root. While the roots are fused all the way down, it has its own apex.

The CBCT is a map for retreatment. It tells us exactly where to look to find the missing canal.

This patient returned to her previous endodontist for retreatment.

I know each one of these endodontists, and they all do excellent work. I confidently suggested to each of these patients that they return to their previous endodontist for evaluation. Using the CBCT map for retreatment, I am confident each one of these endodontists will find the additional canal. One endodontist is retreating at no charge, one endodontist is refunding patient and she will have treatment in our office, and the third patient did not want to return and has elected to pay for retreatment in our office.

CASE #4 - My Missed Canal Found with CBCT

I completed this RCT in Nov 2011. Palatal lesion seemed to improve, but patient symptoms returned. In this particular case, I found only 2 canals. After extensive searching under the microscope, I determined that this must be one of those tricky 2 rooted Mx molars. Since symptoms returned, we took CBCT to see if I missed anything.

CBCT reveals that I did miss a DB canal. However, looking closely at the axial view, my assumption that this is a 2 rooted molar was correct. The palatal and DB roots were fused as one. Sagittal view shows the missed DB canal. Axial view shows the missed DB as well. The CBCT is now a map for retreatment.

As explained, the axial and sagittal view provided by CBCT is invaluable. More information provides for better treatment. This post should demonstrate the level of complexity of molar endodontic therapy even with the use of the operating microscope and the benefit of 3D imaging over 2D imaging alone.

Challenging Isolation

Occasionally, as an endodontist, we are referred a patient for a difficult, maybe questionable, save. This patient was 85 years old and was undergoing cancer treatment. He was referred late one afternoon for treatment of #32. The referring dentist had started the root canal treatment earlier in the day and had stopped due to difficulty locating the mesial canals. The patient arrived with his tooth anesthetized and with IRM in the access. Tooth #32 is the distal abutment of a longspan FPD, and the dentist was confident that it could either be saved or a new FPD fabricated and fit.

Upon access, it was immediately clear why the tooth was a challenge for the referring dentist (if being a tilted third molar bridge abutment on an elderly patient wasn't enough). The mesial gingiva had overgrown beneath the FPD and there was still caries everywhere. Both saliva and blood were flooding beneath the rubber dam and into the access.

After cleaning the caries, resecting the gingiva, and controlling the hemmorhage with astringedent, I called the general dentist on his cell phone to have his restorative input. There was minimal supracrestal tooth structure remaining on the mesial, and I questioned the restorability of the tooth. The dentist was dismissive of any alternatives and confidently requested I complete the treatment.

At this point, something needed to be done to maintain a clean dry field. It became clear very quickly that our normal ancillary use of Oraseal calk was not enough. I had my assistant maintain a steady stream of air on the tooth while I inserted size 6 hand files into the two mesial canals, and a size 30 file into the distal canal. I would recommend lubricating the files with vaseline before placing them. I then maintained the air stream while my assistant mixed up a loose batch of IRM. I placed the IRM and compacted it within the access and around the files before trimming back the material that flowed out beneath the crown.

As the IRM set, I moved the files in a circular patterns to prevent them from locking in and to create a funneled pattern of space. Upon setting, I removed the files and was left with perfect pathways. Through these, I did my cleaning, shaping, and obturation.

Here is the final result:

This technique can be applied to any situation in which caries is removed beneath a fixed restoration, and the restoration is to be maintained to hold a rubberdam and act as a temporary.

If you have any questions or clinical tips to share of your own, please post them in the comments below.

Also, if you are new to the blog, you can also see more of my cases on my office's facebook page: www.facebook.com/alpharettaendo

Thank you!

Internal bleaching makes us smile!

This 13 yr old young lady had some trauma to #8 during a softball game. As you can imagine, the discoloration is of significant concern to the patient.

At the time of the exam, tooth #8 is non-responsive to thermal testing, normal to probing and mildly percussion sensitive. DX: Necrotic w/ SAP. RCT recommended with internal bleaching for esthetic purposes.

RCT completed under microscope assuring that all internal staining is removed from the pulp horns. A coronal barrier is placed in the cervical portion of the tooth. The purpose of this barrier is to prevent bleach from entering the root, passing through dentinal tubules and causing an inflammatory reaction in the pdl. Bleach (Ultradent - Opalescence Endo) is placed in the pulp chamber with a thin, button cavit temporary. Pt is rescheduled for 1 week.

Pt is excited with the new appearance of her tooth.

Final restoration is placed. Endodontists can be a valuable team member in your cosmetic cases!

Value and Limitations of CBCT in Endodontics-Case Report

For the longest time, I have been skeptical of the ability of the CBCT to detect vertical root fractures. Especially in previously treated teeth, where scatter radiation produces artifacts in the image. There has been research(mostly in vitro) supporting CBCT imaging for detecting fractures(Hassan 2009), and there is no doubt that the technology shows exciting promise for use in our field. This case demonstrates both the value and limitations of this exciting imaging system.

The patient first presented six months ago with new crowns on teeth #30 and #31. His symptoms were described as a spontaneous ache and a soreness to mastication that started with the new crowns and felt localized to #31. Diagnostic testing revealed percussion sensitivity and a lingering dull ache to cold on #31, as well as a mild soreness to bite forces on #30. The original root canal treatment and post on #30 were over 15 years old. A diagnosis of irreversible pulpitis was made for #31 and treatment was completed. The mild bite soreness on #30 was attributed to a heavy occlusion and/or some referred pain from #31. Here is our post op radiograph:

The patient reported an episode of severe spontaneous pain lasting one day in the area that started four days after the first visit for #31 and resolved prior to his second visit. This odd experience certainly raised some alarms for me, but when he returned, a new exam and series of diagnostic tests produced nothing of note.

At three months following treatment, the patient reported continued discomfort to mastication in the region. An exam and diagnostic testing produced some continued bite soreness on #30. A new periapical radiograph revealed a possible missed DB canal:

I also speculated on what appeared to be the early formation of a lateral radiolucency on the mesial root that could be the result of a vertical fracture:

However, there were no significant probing depths, only mild symptoms, and no obvious signs of an apical radiolucency. At this point, to aid in our diagnosis, I recommended a CBCT. I reviewed the scan at length individually, and with a periodontist and with an expert from the company. I immediately confirmed the missed DB canal, but also noticed an obvious radiolucency associated with the distal root. What we could not find, independantly or together, was any sign of a fracture in the mesial root or of any lateral bone loss along the root.

It's remarkable the accuracy with which we can pick up the missed DB canal and see the periapical radiolucency (PARL) that was not evident on the periapical radiographs above.

With the new diagnostic information, the decision was made to retreat #30. Of course, I still warned the patient about the risk of losing the tooth if a fracture is found in the root structure. Upon access, I was greeted with the familiar sight of purulent drainage pulsing up the distal with each heartbeat:

Below you can see the missed DB canal before and after post removal: Unfortunately, upon cleaning up the mesial, two fractures were found leading to the MB canal. One along the mesial wall:Another fracture was found along the MB wall: These large fractures probably form a wedge out of the MB root. Unfortunately, they severely compromise the prognosis of our treatment. I cleaned and disinfected the untreated DB canal before placing calcium hydroxide. I then closed the tooth and recommended extraction to the patient. Because of our diagnostic efforts involving a lengthy consult with clinical and radiographic images, the patient was understanding of his situation and appreciative that every effort was taken to diagnose his problem and save his tooth.

In this case, I had high hopes that the CBCT might confirm my suspicion of lateral bone loss around the mesial root. The CBCT was excellent, as it has been in the past, at confirming missed canals. However, it has still not demonstrated to early detect a vertical root fracture prior to an obvious clinical and periapical radiographic presentation.

If anyone has any questions or input, or has had different experiences with the CBCT. Please share them! Also, check out our office's facebook page at www.facebook.com/alpharettaendo where I post new cases regularly.

FAIR Health Consumer Cost Lookup

FAIR Health is an independent, not-for-profit organization that was established to maintain a database to help insurers and consumers determine reimbursement rates for out-of-network charges, and provide patients with a clear, unbiased explanation of the reimbursement process. This first-of-its-kind database will allow consumer to get cost estimates for medical and dental procedures in their geographic area. The database will also help consumer estimate how much their insurer will reimburse for procedures performed "out of network". This website should help patients to clear the cloak of secrecy around the "out of network" reimbursements that the insurance companies work so hard to maintain.

If you think the insurance companies set this up to help consumers understand the insurance process, then think again. This is part of the large settlement following a 2009 investigation by New York State Attorney General Andrew Cuomo that discovered a conflict of interest between the Ingenix database, which was used by insurers nationwide to set reimbursement rates for "out of network" health services. Ingenix happened to be a subsidiary of UnitedHealth, the second largest insurer in the nation. It was determined that Ingenix had a vested interest in helping set rates low so companies could underpay patients for "out of network" services.

You can check out the website, and encourage your patients to use it too!

http://www.fairhealthconsumer.org/

This, Not That, Follow up

I realize that my last post was a little short. It was meant for the reader to contrast two root canal treatments on maxillary second molars and draw conclusions about differences. The obvious, and most important difference, is the treatment of 4 canals in the first case.

Here is the preoperative radiograph again:

History: This patient has had symptoms on and off in the upper left for six years. She cannot chew comfortably on this side and feels a constant pressure in the area. She cannot walk up stairs without feeling dull pain in the area. The original treatment on #14 was performed in 2006 or 2007. Tooth #14 was then retreated by an endodontist in 2009, followed by persistent symptoms, and then treatment of tooth #15 soon after. With retreatment of #14 and treatment of #15, her symptoms improved for a short time, but soon returned.

Med History: Non-contributory.

Extraoral Exam: Alert/responsive, no extraoral swelling, significant asymmetry, or lymphadenopathy.

Intraoral Exam: All tissues normal in color and consistency, no swelling, no sinus tract, crown margins in tact. Large porcelain fracture on the occlusal of #15. All probing depths were 2-3mm with minimal signs of gingival inflammation.

Diagnostic tests: Tooth #15 was responded with a mild tenderness to percussion, both tooth #14 and tooth #15 were sore upon selective bite forces.

Radiographic Exam: Large radiolucency centered on #15 but overlapping the distal of #14. Widened PDL mesial #14. 3 canals obturated #15. Large, possibly strip perforated, canal preparation in the middle and cervical third of both #14 and #15, possibly compromising root strength.

The patient understandably harbored a very negative opinion of the success rate of root canal therapy. When patients harbor this attitude, treatment planning long, challenging retreatments with less than perfect success rates is usually out of the question. I recommended extraction of tooth #15, especially since saving the tooth would also require the investment of a new crown. I offered the alternative of a CBCT evaluation to aid in treatment planning any approach to saving the tooth. The patient understood my concerns, and opted for the CBCT. Here are some selected images from the CBCT.

Circled is the MB root in cross section. From this view, it becomes apparent there is untreated canal anatomy in the form of a MB2 canal.

Even still, having looked through the CBCT images, I recommended extraction as the most predictable course due to the size of the lesion and the compromised tooth structure. The painted a pretty grim picture, but the patient asked me to take a chance on tooth #15 and consented to a guarded prognosis.

Upon access of #15, I was greeted with this view:

Circled is the site of the untreated MB2 canal.

Following 2 hours of uninterrupted work at the first visit, where I had to fight to unledge all 3 previously treated canals, and was ultimately unsuccessful with the distal, calcium hydroxide was placed. The MB2 canal, while easy to see with the microscope, still consumed a majority of the time to navigate. The patient reported all symptoms resolved immediately following return of sensation, an unexpected result. She was able to run up stairs without pain that same night.

Here is the final obturation:

As you can see, still short on the distal where it was ledged. Some of the previous obturation in the palatal was unfortunately extruded. MTA was placed as a coronal seal in the cervical third and across the pulpal floor. Unknown to me at the time, she contacted her previous endodontist (in another city), who she still has a good relationship with to inform him of the outcome. She said he didn't believe there was another canal in #15 and will likely be requesting CBCT and clinical images...I haven't heard from him yet though.

It is unfortunate that so many patients I see have had unsuccessful experiences with dentistry and root canal therapy leading to negative opinions of the treatment options and profession. These patients are in our office literally every day, asking why? why? why? Here is another case of failure that required a consult lasting an hour and half to help the patient understand her condition, the etiology, and the treatment options (not many in this situation unfortunately). Having invested significant time and money in her teeth without success, it was challenging (understatement) to earn her trust in my diagnosis and plan.

#18 has a sinus tract tracing to the furcation radiolucency and a clinical class 2 furcation.

#19 has a narrow isolated 8+mm probing depth along the MB with an obvious apical-lateral lesion extending up the root.

For more case reports and content, please follow Alpharetta Endodontics on Facebook. www.facebook.com/alpharettaendo

Are Implants the Future of Dentistry or Just a Step Along the Way?

The real future in medicine and dentistry is in regenerative therapy. While restorative materials including cements, resins, rubbers, metals, titanium etc. are the best materials we currrently have to replace damaged, diseased or missing teeth, the big picture is to replace damaged tissue with regenerated tissues. The dental pulp stem cell has been identified as a source undifferentiated mesenchymal stem cells which may have ability to differentiated into cardio-myocytes, neurocytes, myocytes, osteocytes, chondrocytes and adipocytes. So while our current restorative materials/techniques are the best available in the world, the future of dental care is tissue based rather than titanium based.

While regenerative treatments in dentistry are still years, perhaps decades away, endodontists are beginning to explore this area with what is called pulpal revascularization. This concept of taking a necrotic pulp in an immature root and stimulating revascularization of the pulp canal to allow for continued root development. Yes, I said continued root development. That is a completely new concept.

Here's another case report.


This 9 year old was at home and jumping on the bean bag and someone pulled it away, caught his tooth and completely avulsed tooth #8. It was out of the mouth for 20 minutes and properly replanted by the pediatric dentist.

A couple weeks later, symptoms presented. The tooth was opened, debrided and pasted with Ca(OH)2 paste.

Shortly after (<2 weeks) the tooth was reopened, instrumented lightly to apex, irrigated with 5.25% NaOCl, rinsed with saline and dried with paper point. A file was then used to pierce the periapical tissues to induce bleeding into the canal. An MTA coronal barrier was placed with wet cotton and IRM temporary. PLEASE NOTE THE PA LESION

At 3 month recall the tooth is asymptomatic and pa lesion has resolved.

At 9 month recall the tooth is asymptomatic and fully functional. No percussion pain, normal probings and NORMAL RESPONSE TO EPT. While there is no reaction to thermal testing, there is definitely a normal response to ept.

Looking closely at the radiograph you can see that the dentin walls in the apical portion of the root have thickened and there appears to be dentinal bridging forming in the mid-root area.

While this procedure has also been called pulpal regeneration, some argue that it should be called pulpal revascularization. It is not completely known what type of tissue that is growing into the canal or the source of that tissue (cells from within the canal or migrating in from the periapex). The continued development of the root and healing of the lesion however, is not debatable.

This type of novel treatment may give us a glimpse of the future of dental treatment using tissue regenerative techniques rather than artificial tooth replacement with traditional restorative materials.

For more information regarding the considerations of this procedure, click here.

To see more cases of pulpal revascularization, click here.

Who Cares About the Periodontal Ligament?

Congratulations to the manufacturers and marketers of dental implants! We now have patients with perfectly good teeth considering removal and replacement with implants on their very own! We are actually seeing patients that are convinced that an implant is better than a natural tooth!

I was once at a seminar where a specialist was discussing implants to a group of endodontists, when I asked a question regarding the periodontal ligament, the lecturer replied, "Who cares about the periodontal ligament?". Perhaps that is a good questions to ask?

The periodontal ligament is the difference between a natural tooth and an implant.

While implants are an ideal way to replace a missing tooth, an implant will never be able to replace the periodontal ligament.

I think perhaps we overlook the benefit of having a periodontal ligament in our haste to condemn a tooth and replace it with an implant.

The periodontal ligament is the dense, fibrous connective tissue that connects the tooth to the bone. It is vital in the transmission of masticatory force from the tooth to the bone. It acts like a shock absorber, giving the tooth some movement in the socket. It provides proprioception, or feeling to the tooth. Without proprioception, we can have traumatic occlusion and have no sense of it (ie. fractured porecelain). The periodontal ligament also has an important interaction with the adjacent bone. If you loose the ligament, you will also lose bone. The periodontal ligament is the home to important cells such as osteoclasts, osteoblasts, fibroblasts, cementoblasts, cementoclasts, undifferentiated mesenchymal cells (stem cells). These cells are all important in the dynamic relationship between the tooth and the bone. These cells are important in orthodontic movement or extrusion. The periodontal ligament and its associated cells may be the only real consistant way to stimulate bone growth.

Consider the long term effects of losing a tooth (and its periodontal ligament) and replacing it with an implant...

1. The implant cannot be moved in any direction from its integrated position.

2. There WILL be crestal bone loss initially.

3. There WILL be crestal bone loss over time - up to 0.2mm/year

4. There will be loss of proprioception

5. With loss of crestal bone come loss of gingival height and esthetic issues.

As I mentioned, implants are a great way to replace MISSING teeth. But they are not alternative treatment for restorable teeth.

This patient was seen over 3 years ago. Tooth #8 was diagnosed as necrotic w/ acute apical abscess. She had swelling and pain at the time. Antibiotics were prescribed and RCT recommended.

Patient has returned again today with swelling and pain. She reports that she did not have RCT done because the swelling and pain went away. There is no mobility, despite the increased size of the lesion. The RCT has been recommended again. Unfortunately, due to previous experience with root canals, she is convinced that they are less successful than an implant.

Proper understanding of the role of the periodontal ligament with this tooth should help her decide the only acceptable way to treat this tooth is with endodontic treatment.

This, Not That.

Short one today.

This is what a maxillary second molar root canal treatment should look like:


Rethink what you are doing if your cases look like this: