Wednesday, December 21, 2011

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.

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Thursday, December 8, 2011

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.

Monday, November 28, 2011

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.

Thursday, November 17, 2011

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:

Wednesday, November 9, 2011

Consult Along: A Day at Alpharetta Endodontics

Rather than try to have an overarching theme to this post, I will present each of today's patients as each case was complex and each illustrate rather important points. For the sake of brevity, I will only post significant findings (and I apologize for poor consistency and errors in grammatical tense) . Unless otherwise stated, assume medical history is non-contributory. I would love for readers to post feedback, alternate treatment plan ideas, or other approaches to these cases.

Patient 1:
This patient presented with a history of root canal treatment on #20 by an endodontist 1-2 years ago. #19 was treated by her general dentist ~8 months ago, and #18 was fractured and replaced with an implant within the last two years. The crown came loose and was replaced with a post 1 month ago. Following this treatment, she described severe pain upon chewing and swelling on her tongue side of the tooth. There is no extraoral sign of swelling or lymphadenapathy. No intraoral swelling or sinus tract. Around #19, the gingiva is edematous and inflamed with bleeding on probing. The crown margins are open and overextended. The probing depths on #19 are 3 mm interproximally and 8-9mm mid buccal and mid lingual. The radiograph reveals a laterally widened PDL with a hint of an apical radiolucency. The restoration on the mesial is into the furcation and associated with horizontal bone loss. #20 displays an apical radiolucency as well. The implant on #18 is bulbous and overcontoured to the mesial with some signs of horizontal bone loss.

Unfortunately, I recommended extraction of #19 due to the likelihood of a vertical root fracture and a poor restorative prognosis. I recommended she return to her previous endodontist for reevaluation/recall of #20. I also provided her some proxibrushes to maintain oral hygiene around #18. Would you rather have that root canal/crown or that implant...or neither?

Patient 2:
This patient is referred by her general dentist for evaluation of #3 and initially presented two weeks ago. She reports having root canal therapy a year and a half ago by another local endodontist, no microscope. Since the time of treatment, she has had spontaneous "shooting" pain that is localized to tooth #3. It is worse in the morning and with mastication. A history of symptoms indicates that the tooth was likely vital preoperatively and so persistent bacteria is not a feasible etiology. No extraoral swelling or lymphadenopathy. No intraoral swelling or sinus tract. Probing depths 2-3mm, crown margins are in tact. Occlusion is light in MI with no interferences. No palpation tenderness, no swelling, no sinus tract, no percussion tenderness, no mobility. Slight bite pressure tenderness on the MB cusp and P cusp only.

Preop, no radiolucency, slight ligament widening in the palatal, short palatal obturation, overenlarged mesial obturation in the cervical third, undermined/weakened mesial tooth structure. Diagnosis: previous treatment/acute apical periodontitis. Possible etiology: restorative recontamination, root fracture, strip perforation of MB/MB2. I recommended retreatment but cautioned that a finding of a root fracture would indicate a need for extraction.

Upon access, blood was found on the palatal canal, and, in spite of anesthesia, the GP was tender to pressure with fluid built up around it. No fractures were found. Additionally, a strip perforation was found in the cervical third of MB2. It was repaired with MTA and the palatal canal was retreated. The patients symptoms resolved immediately, and the case was finished this morning.

Patient 3:
This patient went to her new dentist for a broken restoration on #30. Decay was found encroaching on the pulp chamber and she was referred for root canal therapy. She is asymptomatic. #31 was treated 2 years ago by another endodontist, no microscope. The anatomy appears to be very challenging. A history of symptoms of cold sensitivity and throbbing pain prior to the previous treatment indicate that #31 was likely diagnosed as irreversible pulpitis preoperatively.

Treatment on #30 was completed at today's visit and treatment options for #31 were discussed. Restoratively, the case is compromised with a crown on a buildup with voids. Additionally, retreatment of the mesial root is going to be challenging if not impossible. If, as it appears, the distal root is the primary source, retreatment may be successful. One alternative, if retreatment is not successful, is to place spacers to loosen the tooth and then try an intentional reimplantation. Apical surgery is difficult to impossible in this location with such long roots (25mm working length on #30).

Patient 4:
Asymptomatic, original treatment over 15 years ago. Her crown and posts came off and extensive recurrent caries was found beneath. Her dentist cleaned the area and placed a temporary crown before referring her for evaluation. While radiographically, the ligament is in tact, her history indicates bacterial contamination and retreatment was recommended.

Case #5:
This patient is asymptomatic. She recently moved here and her new dentist noted a parulis buccal to #30. She is ~85 years old. Probing depths were 2-3mm with bleeding on probing and a class 1 furcation involvement. The margins on the composite were open. Due to the compromised restorative prognosis and the furcation radiolucency, I recommended extraction. She does not wish to replace this tooth at this time, but an FPD is likely her best option. She is fortunate to have full molar occlusion on her left side.

I hope that our readers learned something from these cases. You will probably realize that I started no new root canal treatment today, and that all our cases were complex diagnostically and involved molars. This is typical for our practice.

If you have any input or questions, please voice them in the comments, but please remain constructive. As always, I invite readers to see more cases posted regularly on our facebook page at

If you have any suggestions or requests for future posts, please leave them in the comments!

Thursday, October 27, 2011

Saving Teeth: Repairing a Resorptive Defect with MTA

In 2006, #19 was diagnosed as necrotic pulp w/ acute apical periodontitis. An irregular radiolucency was noted on the mesial aspect of distal root. This was diagnosed a resorptive defect. While some may have elected to remove the tooth and place an implant or bridge, this patient wanted to preserve her tooth, so a root canal and root repair was performed.

During our RCT procedure, the resorptive defect was cleaned out without perforation of the root. The appearance of the post-op radiograph appears to show some kind of communication.

At 20 months, the patient returned for recall and a large furcal lesion was present. Once again, more may have elected to extract the tooth and replace it with an implant or bridge. We discussed options/prognosis and decided to retreat and try to repair the resorptive area with MTA.

#19 was retreated and resorptive defect repaired with MTA. You can see the resorptive defect was opened more aggressively and there was extrusion of MTA into the periodontal ligament.

3 year recall (since the retx and repair with MTA) shows complete healing of the furcal lesion. The tooth is fully functional and asymptomatic. This is a tooth was was saved by endodontic therapy using the right material. This tooth was saved by endodontic therapy and the use of MTA to repair and seal the resorptive defect.

Monday, September 26, 2011

Avoiding Root Canal Therapy with MTA

Dr. Hale's excellent post on pulp canal obliteration inspired me to share these few cases where a coronal barrier was also used to avoid root canal therapy. The most recognized reason to avoid complete pulpal debridement is biological, to maintain pulpal vitality, and thus continue root formation, subsequently improving fracture resistance, but there also exist technical limitations on the debridement procedure, imposed by anatomy or resorptive defects, that might prevent success of conventional root canal therapy.

This first example is a straightforward partial pulpotomy (or Cvek pulpotomy) with an MTA direct pulp cap. This patient had cerebral palsy and toppled out of his wheel chair causing a complicated (pulpal involvement) crown fracture of #10. You will note #9 was treated at this time as well, and if I recall correctly, was discolored and non-vital from a previous similar trauma. Multiple dental injuries (and traumatic injuries of all kinds) are very common in CP patients due to negative effects on balance. Fortunately, working with a pediatric dentist who scheduled OR time, the patient was seen within two days of the incident and the pulp vitality of #10 was maintained. Remember, inflammation in traumatic exposures very slowly spreads apically, and immature pulps with large vascular supplies are largely resistant to necrosis in the short term.

1-Year Recall
Please note the complete root formation.
At a 1 year recall, #10 responded normally to vitality testing. Radiographs revealed a complete formed root and a dentin barrier beneath the MTA. Astute viewers will note this success is amazingly in the absence of a coronal restoration (unfortunately, not the only time I've seen bare, unrestored MTA pulp caps succeed at 1 year recalls).

This next case is similar, although a little less conventional. As you can see in the preoperative radiograph, the root is severely dilacerated. While certainly it is possible to perform root canal therapy on this type of root (see my previous post for an arguably more challenging S curve), the difficulty level is unquestionably high. This treatment plan not only reduces the risk of instrument separation, but also saves the patient time and money, and the operator from fatigue.
The key here is that this was an asymptomatic carious pulp exposure. In the case of symptoms of irreversible pulpitis, it is generally thought that an MTA pulpotomy is a more risky procedure. It is certainly contraindicated in cases with symptomatic apical periodontitis (although I have had success direct pulp capping an immature tooth with apical periodontitis).

This last case is open to the most controversy. This patient had multiple large composite restorations across the anterior maxillary dentition. He admitted to being far more motivated by financials than esthetics. His previous composite restoration and crown had sheered off unconventionally at an oblique angle to the buccal leaving a substantial cingulum. The fractured portion had been rebonded by his general dentist. This tooth had a history of trauma over 40 years ago and some extensive external resorption is visible overlapping an obliterated pulp chamber and canal. The PDL is definitely in tact and there is no history of symptoms. The option of extraction and implant placement was discussed and encouraged. The alternative treatment plan chosen by the patient is less than ideal and the patient was more than okay with a compromised long-term prognosis. I intentionally described a grim outlook to the patient, as I do with most unconventional treatments, although here I can admit that I am confident in the predictability of the patient's choice. As you can see from the preop radiographs, conventional root canal therapy is impossible due to the irregular resorptive defect sandwiched between obliterated canal space.

I am still waiting on the general dentist to forward over a restored recall radiograph. Hopefully I will have the image to edit in by the end of the week. You can see the post space that I prepared using a 2 round bur and a gates-glidden with the tip flattened. The post space communicated with the resorptive more coronal than I anticipated, necessitating the use of MTA as a sort of resorptive cap. I feel as long as the area remains aseptic, it is reasonable to assume a successful result.

Here is a bonus case posted on our facebook page, . I'd encourage everyone to follow there (and check the backlog of case photos) for more interesting cases.

The patient's symptoms were intermittent, spontaneous, a 6 or 7 out of 10 on the pain scale, occasionally throbbing, and worse with mastication and pressure. The key history here is the patient's remark, "it feels like my gums are coming loose from my tooth."

Make the diagnosis. I have obviously helped by circling the key components.

Friday, September 16, 2011

Calcific Metamorphosis (Pulpal Obliteration) and Internal Bleaching

It has been reported that 11.6% - 33% of boys and 3.6% - 19% of girls suffer some kind of dental trauma before age 12. Internal staining is common following a traumatic injury to a tooth. Calcific metamorphosis is the partial or complete obliteration of the pulp following dental trauma. An interesting study of 168 traumatized, discolored, anterior teeth found that 47.6% were partially obliterated, 31.6% were totally obliterated, and 20.8% were found necrotic. Necrosis was more associated with fractured teeth, while pulpal obliteration was associated with subluxation and concussion injury. It was also noted that injuries suffered in the 1st and 2nd decades of life resulted in more pulpal obliteration, while those suffered in the 3rd decade resulted in necrosis more often.
To remove this discoloration, typically endodontic therapy is performed and internal, non-vital bleaching is performed. The following case is a variation of this procedure.

This 13 year old boy previously suffered a traumatic injury. Tooth #8 has discolored. The tooth is asymptomatic. Non-responsive to thermal testing, normal to percussion and probing.
It was decided to perform endodontic therapy, prior to internal bleaching to improve the esthetics of this tooth.

Partial pulpal obliteration is noted. A 1mm thick calcific barrier is found just below the level of the CEJ.

RCT is initiated and a complete calcific barrier is noted. It was decided to perform the internal bleaching without endodontic therapy.

A standard internal coronal barrier (glass ionomer) is placed over the calcific barrier to prevent internal bleach from exiting through cervical dentinal tubules and causing an inflammatory reaction in the pdl. A walking bleach technique is used. (Opalesence Endo)

After 1 week, pt returns and the internal bleach is removed. This tooth will be recalled to monitor vitality over time.

If pulpal obliteration occurs without necrosis, there may not be a need for endodontic therapy prior to internal bleaching. If a coronal barrier can be placed, without exposure (and possible contamination) of the pulpal tissue, then it would seem that internal bleaching could be performed without the need for complete endodontic therapy. Long term recall to monitor vitality will be done with this type of approach.

Adeleke O Oginni
and Comfort A Adekoya-Sofowora
"Pulpal sequelae after trauma to anterior teeth among adult Nigerian dental patients", BMC Oral Health 2007, 7:11doi:10.1186/1472-6831-7-11.

Thursday, September 1, 2011

Cone Beam (CBCT): To Use or Not to Use?

There has been some discussion about the indications for use of CBCT in endodontics. The AAE and AAOMR released a joint position statement regarding the use of CBCT in endodontics.

The section on patient selection criteria states, "CBCT must not be used routinely for endodontic diagnosis or for screening purposes in the absence of clinical signs and symptoms. The patient’s history and clinical examination must justify the use of CBCT by demonstrating that the benefits to the patient outweigh the potential risks. Clinicians should use CBCT only when the need for imaging cannot be answered adequately by lower dose conventional dental radiography or alternate imaging modalities."

I would suggest that there are times when a clinician has no way of knowing what additional information a CBCT would provide prior to starting treatment. This information may often prevent complications, such as perforation, which potentially could affect long term prognosis.

The following case is a perfect example.

This patient came to SSE for emergency treatment. #18 DX: Necrotic pulp w/ Symptomatic Apical Periodontitis. RCT initiated. 3 canals located, however a 4th distal canal is not found. 2 distal roots are apparent the pre-op film. The ML, MB and a distal canal are located. The distal is opened looking for the 4th canal. After 20-30 minutes of searching for 4th canal, the patient is re-appointed for 2 step treatment.

Upon return for second visit, the symptoms of SAP have not completely resolved. Slight vestibular swelling noted. We decided at that point to take a CBCT to help us located the 4th canal.

The CBCT clearly shows us that a perforation has been created (red arrow), and the additional canal/root is lingual to the DB canal. A sagittal view, provided only by CBCT, can provide information that is not available by conventional radiography.

With these images, the 4th canal is easily located within minutes of opening the tooth.

In this case, a CBCT provided valuable information that identified location of the 4th canal. If taken prior to starting, the 4th canal would have been located more quickly and without the small perforation in the distal.

I am not suggesting that CBCT should be used on every patient, but I am suggesting that with multiple rooted teeth, the sagittal & axial view provided by CBCT can save time and prevent endodontic complications, both of which provide justification for a more routine use of CBCT in endodontics. In our practice at SSE, the CBCT is not a profit center. We have priced these images to make them affordable to all patients. Our implementation of CBCT is to provide the highest quality of endodontic care available.

Wednesday, August 17, 2011

Persistent Post-Treatment (Apical) Periodontitis.

When endodontically treating a tooth experiencing symptoms to percussion, that is symptomatic apical periodontitis or acute apical abscess, it is reasonable and normal to expect those symptoms to persist a few days following treatment. I make it a point to explain to patients that this sensitivity is emanating from the periodontal ligament surrounding the tooth, and, just like a sports injury, ligaments require time to heal following removal of the insult (bacteria in teeth). However, occasionally we evaluate a tooth that has had symptoms to percussion for an extended period of time. In this post, I will discuss the sources of these symptoms and how to diagnose and treat them. I will also show a few cases of persistent apical periodontitis and how they were managed.

Before we get into diagnosis and cases, it is essential to understand the sources of apical periodontitis. With few exceptions, the source of symptoms is either trauma, occlusal or otherwise, or bacteria, apical or otherwise. It really is that simple. It is up to the clinician, through history and exam, to determine the source of symptoms.

Briefly, a common scenario would be a tooth with an apical radiolucency, sensitivity to percussion, and a lack of cold response. Our diagnosis is necrotic/symptomatic apical periodontitis and the source of both is bacteria. By removing the insulting bacteria with root canal therapy, we can resolve the apical periodontitis and the radiolucency will heal with time. The below images are from a patient with that exact scenario and illustrate an important point.

This #18 clearly has a challenging s-curvature in the apical third of the mesial root. If we are unable to instrument and clean around that curve, we run the risk of bacteria persisting, and consequently, symptoms persisting.
Fortunately, with a little luck, I was able to clean around the curve and the patient's symptoms resolved within a day of initiation of treatment and calcium hydroxide placement. Also, note the mid-mesial canal. There is an important point here:

With a necrotic tooth, if symptoms persist following treatment, especially if the treatment is deficient in cleaning or rife with errors such as a perforation, then we must suspect bacteria as the source and look to treat the tooth endodontically (possible retreat and/or surgery).

Here is another scenario, this patient was referred for evaluation and treatment of symptoms in the lower left. Symptoms were described as a short, sharp sensitivity to chewing over the past year and a half, and a moderate sensitivity to hot and cold that lingers for a few minutes over the past few months. The patient points to #19 for the chewing sensitivity and farther back for #18. Clearly, we have two issues at hand as an endodontically treated tooth will never cause the type of sensitivity described by the patient.

The previous root canal treatment was done by an endodontist a year and a half ago. This endodontist evaluated the patient and placed him on penicillin and methylprednisone. I must stop here and say that I do not support treating this situation with these medications. I have never felt compelled to prescribe steriods and rarely prescribe antibiotics. It is easy to understand why when we realize that neither of these medications will address the possible sources of the patient's symptoms. Permanently resolving the inflammation will not happen without removal of the trauma source and systemic antibiotics will not have any effect on bacteria within a root end. Symptoms can be masked, but even a placebo can help a patient's symptoms. In this case, following medication, there was some improvement in symptoms but they soon returned.

Let us ignore the cold sensitivity for a minute, which was traced to #18, found to linger and be associated with a cracked tooth, and was treated appropriately. What questions are important to ask the patient at this point? Maybe we can deduce the diagnosis of #19 prior to treatment. As it turns out, with more specific questions, I learned that the tooth was cold sensitive prior to root canal therapy, and that these symptoms resolved. I also learned the tooth was actually asymptomatic until the crown was placed a few weeks following treatment. Now, I can proceed to the clinical and radiographic exam knowing that the most likely cause of apical periodontitis is a traumatic occlusion, since even a poor root canal on a vital tooth will likely be asymptomatic for many years before bacteria can negotiate to the apex.

Exam revealed #19 to be sensitive to percussion and bite forces (in MI and with a bite stick), and #18 to be hypersensitive with a prolonged cold response and a fracture. I also located a 5mm ML probing depth with associated erythematous and edematous gingiva. The crown on #19 was bulbous, overhanging the lingual, and flat on the occlusal with wide contacts.

In the below radiographs, we see a short obturation on the mesial and distal roots of #19 with some slight and debatable ligament widening. Not a perfect root canal but unlikely to be the source of symptoms.
Another radiograph revealed overhanging cement on the mesial.
Local scaling removed the excess cement and crown recontouring with a diamond bur combined with an occlusal adjustment was performed. The patient returned for treatment of #18 a few days later and all his symptoms from 19 had resolved. A reevaluation in a few months will determine if our treatment worked permanently. Incidentally, here is the completed treatment on #18 (and check out the distal root of 17 curving at the x-ray plane).

The point to be learned from this case is that an accurate and complete history will illuminate possible sources of the problem, exam can confirm that source, and conservative local treatment will often be enough to resolve symptoms. Occlusal trauma is the most common cause of post-treatment apical periodontitis.

Here is a case I treated that exhibited persistent symptoms and is similar in many respects to the one above. The original symptoms and exam were indicative of irreversible pulpitis and extensive recurrent caries was located underneath the buccal margin. I painted a grim picture and recommended extraction. The restorative prognosis was compromised, decay reached into the furcation and alveolar crest. Nevertheless, the referring dentist was confident and capable, and the patient was well informed knowing the risks and that periodontal therapy was in her future. She was anxious to avoid implant treatment due to a prior bad experience with one in another site.

At the second visit of treatment, the patient reported her symptoms to cold had quickly resolved. However, her tooth that was not previously symptomatic to percussion was now hypersensitive to occlusal forces. I had not cleaned long at the first visit, and I had not yet placed the obturation material (not that these usually cause any problems). Likewise, I had merely placed CaOH within the top of the orifices as a barrier to reinfection and not deep into the canals (again, not that this usually causes a problem). The tooth was out of occlusion as well so the only possible source of ligamental inflammation was the buccal area where decay had been removed to the level of the alveolar crest and into the furcation. This area was not well restored yet, merely patched with IRM, and was a definite irritant to the ligament. I cautioned patience, completed treatment, and recommended returning to her general dentist for evaluation and restoration.

When the patient returned for reevaluation a month later, complaining of chewing sensitivity in the temporary crown, I was impressed with the quality of the buccal composite restoration and the buccal gingiva was minimally inflamed. The distal gingiva was inflamed with bleeding on probing. The patient had plans for an evaluation with a periodontist and I again counseled patience with symptoms until all periodontal treatment was complete. The occlusion was found to be heavy in non-working lateral excursion and adjustment relieved the patient's symptoms in the chair.

The important point here is since I had done the initial root canal treatment, I knew that the tooth was vital preoperatively. There is no way I would consider touching this tooth with any endodontic therapy since I know that I cannot improve upon my root canal treatment. The dental history leads me to look for sources of trauma to the ligament, occlusion and biologic width infringement in this case.

One other common cause that I see of persistent apical periodontitis is when a patient wears an occlusal splint or night guard, dentist fabricated or store bought, that is not well adjusted following a new crown on the tooth. Consider how a kids teeth feel after an orthodontic visit and you will understand the source of these symptoms.

This last case was treated by a general dentist 2-3 years ago and has exhibited persistent symptoms that have only seemed to worsen through multiple occlusal adjustments. The dentist reports an instrument separation in the distal root. Her symptoms had only recently become spontaneous and were described as a minor dull ache or pressure. In discussing the situation with the patient, she remembered the tooth being asymptomatic and the crown having been placed years prior to the root canal treatment. She claimed the referring dentist saw signs of a problem on the radiograph and recommended treatment through the crown. Clinical exam revealed no relevant findings and occlusion appeared well adjusted. A distal shift radiograph, the most important radiograph to take on a maxillary molar, displayed an all too common radiographic finding in maxillary molars treated without a microscope, a radiolucency on the mesial root.
The most common cause of this problem and one that we see every week is a missed MB2 (also called MP or ML) canal. This tooth was unusual in that I speculated a missed MB canal outlined below.
Upon retreatment, the untreated MB canal was found and is seen on the below photograph and radiograph.

The patients symptoms resolved quickly following the first visit. Here is the post operative radiograph.

Not all cases of persistent apical periodontitis require endodontic retreatment or surgery. In fact, most don't. By a taking a careful dental history, it is often possible to discern the preoperative diagnosis, which informs how and where bacteria could be causing a problem. It is also possible to create a timeline as to when symptoms first occurred and what events could have initiated them. If symptoms started with restorative work, then carefully examine the occlusion, margins, and gingival health. Only when we have a radiolucency or a smoking gun, like a missed canal, a short obturation in a previously necrotic case, or a case recontaminated with recurrent caries, should we be looking into endodontic therapy as our first choice to solve the problem. Often times, diagnosis is not clear, and I start with the conservative options, occlusal adjustments and periodontal therapy, before proceeding to endodontic therapy. I cannot think of a single instance where I have recommended medication as a primary therapy.

I hope these cases will help those of you out there to think like an endodontist. Some may point out that I have not talked about tooth fractures. I plan to discuss my philosophy on those in future posts. I look forward to any feedback and invite everyone to check out more cases on our facebook page: