Do You need a cbCT to do Endo?

Sometimes, with conventional radiography things just don’t look right . The case seems fairly simple the canals are fairly easily negotiated and things seem to be going very smoothly. In this case this mandibular second molar seemed to be shaping up pretty well. I was able to gain patency in three canals and I had closed the tooth with a temporary composite access filling and was ready to return it to the referring dentist for final restoration.

Unfortunately , the distal root did not look right. The distal root canal filling was not centered in the root and there just seemed to be too much “space” on the distal part of the root adjacent to the canal filling… suggestive of a missed second distal canal

The patient thought he was done ( and so did I!) and I considered dismissing him.  But experience had taught me that I had to look further. I explained that I had to place the rubber dam again, remove the temp and re-examine the case. Although the patient was disappointed that he was not “done”, he appreciated my thoroughness.  I  removed the PermaFlo Purple orifice bond material  and a second disto-lingual canal became visible . The canal was treated and the case was completed as you can see in the bottom radiograph.

It would have been easy to send the case back to the referring dentist and have them place the restoration.  But it is also possible that the patient could have been persistently symptomatic while the radiograph would appear show “good technique”. Further treatment would involve accessing through the new restoration, something that neither the Dentist ( who just placed the restoration) or the patient (who just paid for the intact restoration) appreciates very much !!   In retrospect, a Cone Beam tomograph probably would have been a good idea in this “easy” case.

But do we need to take a cbCT for every case? (Cost $,  Exposure to patient?) Even in the so called “ easy” cases, it is often wise to get 3D imaging to confirm what you think you already know to be true. Canal anatomy has a way of biting you in the ass when you least expect it. More and more, cone beam tomography is slowly becoming an essential part of contemporary, modern Endodontic treatment. If you perform Endodontics without one, these are the kind of mistakes that you are likely to make.

Treatment Plan or Fail ?

For today’s case of the month we discuss treatment planning with regards to this important maxillary first molar distal abutment. The patient presented with evidence of curious involvement of the distal aspect of tooth #26. The contact between #26 and 27 was open resulting in deep distal decay underneath the Crown margin of #26. The referring Dentist took a novel approach of simply cutting a DO preparation into this distal abutment crown, excavating the decay and temporizing it with IRM.

If we simply look at the periapical image, we see that the contact is open and that the open contact has likely resulted in continued problems with maintaining hygiene on the distal aspect of this important abutment tooth. #26 is part of a four unit bridge that is integral to the patients function on this site. The abutments for this bridge are #25 and 26 with a unique onlay/rest on the palatal aspect of #23. The anterior portion of the bridge is cantilevered onto this cuspid, which may have contributed to the lifting and/or opening of the Distal margin of the #26 crown abutment.

Examination of the bitewing radiograph gives us more information and a clue as to why this problem persists. The restoring dentist had placed an opposing mandibular bridge using tooth #36 as a very tilted distal abutment.  Because the distal marginal ridge of #36  was above the occlusal plane, it acted as a plunger cusp forcing open the contact between the two maxillary molars. This situation was destined to create continued problems with food impaction in the maxilla. Unless we addressed this issue, endodontic treatment of #26 and attempted repair of the distal margin or replacement of the MO amalgam in #28 to try to close the contact, would likely fail. This did also not address the cantilever tipping forces on the mesial aspect of the bridge in the area of #s 23 and 24. The whole side was a disaster.

So we were faced with a difficult decision of how to deal with this. One of the ways we could solve problem was to  simply remove the maxillary second molar. Endodontic treatment could be performed on the maxillary first molar and an attempt could be made to repair the distal margin of the maxillary first molar if the patient was not interested in replacing the entire bridge.  This was , at best, a stopgap measure, destined to ultimately fail.  The patient would lose some posterior function due to the extraction of #27 (leaving #37 unopposed,) but this is the price we would pay to ensure that the maxillary bridge could be maintained with proper hygiene. Unfortunately, this would still leave unfavorable occlusal forces on the bridge and eventual loss of the bridge. But it may provide a short term affordable option for the patient. Endo would therefore be necessary of #26 and treatment would need to be scheduled.

Ideally, the bridge should be replaced but this is not always financially feasible. We could also extract #26, and create a new bridge with abutments #23-25 and 27. Again, the rocky occlusal plane in the mandible may make this impossible. For proper restoration, establishment of a more even occlusal plane would be necessary, which would likely involve re-restoration of that side of the mandible, unaffordable for the patient at the time.

So whose responsibility is it to go over these strategies and possible treatment plans  with the patient? And if the patient is just referred for endodontic treatment of #26, is it within the prerogative of the Endodontist to discuss this with the patient ?

Long term endodontic success can only be achieved when the coronal seal is maintained. If we simply Endodontically treat the maxillary molar as requested , I have no doubt that decay will recur and that the long term success of the endodontics may be compromised. 

Furcal Lesion Heals Nicely

Patients are sometimes referred with furcal radiolucencies or furcal involvement that may or may not be of Endodontic etiology. The question always is: How much of the furcal problem is Endo related and how much is Perio? We know that furcal bone CAN be completely grown back IF the problem is Endodontically related. (Something our Perio colleagues can only dream about!). The decision to commence Endodontic treatment on a furcally involved tooth is complex.

The first thing we need to establish is:

(1) Pulpal necrosis 
The pulp MUST be necrotic, at least in the area that communicates with the periodontal breakdown. A finding of normal pulp responses suggests that any furcal or bony breakdown is unrelated to Endo and that Endodontic treatment would be an expensive waste of time and money. Endo won’t help.

(2) The prevalence of Periodontal disease in the rest of the mouth.
Is this an isolated problem, not consistent with excellent periodontal status in the rest of the mouth? Or does the patient have generalized horizontal bone loss and/or chronic Perio disease? If no  bone loss is occurring in other areas of the mouth, then it is POSSIBLE that lateral or furcal anatomy could be leaking necrotic pulp products into the involved area, causing breakdown of the supporting attachment apparatus. In other words, excellent Perio in other areas of the mouth, combined with a pulpal finding of necrosis suggests that Endodontic treatment MIGHT improve the situation. There are no guarantees.

(3) Successful fill of lateral anatomy demands that irrigants and medicaments have adequate contact time with the chamber/canal space to work on any tissue that may be in this lateral anatomy. Single appointment, fast Endo treatment will be unlikely to give these solutions and medicaments the time necessary to digest the tissues enough to allow patency and to accept any filling materials, whether it be gutta percha, sealer or a combination of both.

When presenting treatment plan options to patients in such cases, they must understand that the process may be slow and protracted. Treatment will involve multiple appointments, application of irrigants and medicaments and monitoring of the progress of the case until positive results become visible. In some cases this may be rapid resolution of draining furcally related sinuses or closure of deep pockets. In other cases, teeth are temporized until there is evidence of bone fill, which usually takes between 3-6 months to be visible on conventional radiographs.  Clinicians involved with treatment of the case MUST provide proper, secure, durable, sealed temporization to ensure asepsis and prevent contamination.

Tooth on presentation in my office. Access had been attempted by the referring Dentist and sealed with colored composite.

In this case, the referring Dentist (an excellent GP clinician) started the endo on tooth #36. His referral note was excellent and comprehensive.
“The patient had caries under the crown. The crown was removed, and the caries excavated . I determined that the tooth was salvageable. A temp crown was made and the patient was appointed to do the Endo. Upon access, I had trouble finding all 3 (or 4) canals and was only able to find one. I am referring the case to you. I noted the  furcation radiolucency with subsequent Perio probing that was not present in the radiograph in the patient’s previous radiographs. (Important history!) He suspected that the furcal involvement was of endodontic origin creating an endo-perio lesion.” Great note and good call!!

Diagrams and annotated illustrations help explain the nature of the problem and treatment goals to  patients.

Clean and shape of the canals and Ca(OH)2 medication.
At 4 months and we began to see signs of furcal regeneration.

Canal system obturation was performed with instructions to immediately return to the dentist for final restoration.

The tooth was then beautifully restored. The BW and last 2 periapicals show full furcal regeneration and a nicely restored tooth.

The Need to Confirm the Diagnosis in YOUR Office

A 47 year old female patient was referred to me for endodontic treatment of a maxillary left first molar (#26). The tooth had been restored heavily with a multi-surface composite that appeared to be approximating the pulp . The patient had been having elevated thermal sensitivity and the referring dentist was considering placing a full Crown restoration because of the size of the existing composite. He wished to have the tooth devitalized to minimize the possibility of irreversible pulpitis after final cementation of  the full Crown. The composite restoration appeared to be quite deep and the request seemed reasonable. Endodontic treatment was initiated and completed without incident.

However a few days later the patient called my office saying that the original thermal symptoms have not resolved. The patient was seen for re-examination at which time I noted that the second molar (which was barely  restored with a shallow occlusal composite barely through the enamel), appeared to have a crack running down the distal marginal ridge. The mandibular first molar (#36) had been extracted many years ago and this tooth appeared to be in greater than normal function due to the lack of opposing dentition. Transillumination confirmed the presence of the crack and thermal tests confirmed that symptoms were coming from #27, the second molar.

The tooth was accessed and a crack was noted on the occlusal surface running across mesial distally. Endodontic treatment was completed without incident and the patient’s symptoms disappeared.

Methylene Blue Dye was used to stain the crack

The original referring dentists request seemed reasonable, considering the history of #26 and his need to restore it. However because I did not perform pulp tests on the adjacent tooth and  I assumed (incorrectly) that the patient’s symptoms were coming from this heavily restored first molar. (I perform a lot of “elective Endo prior to prosthetics, so this request is common.) 

The lesson to be learned from this episode is that well meaning dentists may have good intentions, but it is still important to perform diagnostic procedures in your office and not rely upon other’s  recommendations or diagnosis before initiating treatment in your own office.

Classic Maxillary Molar Retreatment

A 53 year old male patient was referred to me for endodontic consideration of tooth #26. The patient had pain for five days and was awakened at night. The pain was described as 9 out of 10 and localized to the tooth and buccal gingival area adjacent to #26.   The pain was constant and the area was not sensitive to cold or heat . It was increased by biting and eating and was relieved by use of NSAIDs.  The endodontic treatment appeared to be approximately 20 years old and the tooth was never restored with a full cuspal coverage restoration. Clinical examination showed positive response to chewing percussion and palpation. Mobility was within normal limits. Perio findings were WNL.

Radiographic examination showed a diffuse radiolucent area associated with both mesiobuccal and distobuccal roots . CBCT confirmed this finding with minimal associated radiolucency in the Palatal root area. However, the Palatal gutta percha cone appeared to be buckled and “accordioned” in the palatal canal, indicating less then optimal obturation.   There only appeared to be one canal filled in the mesiobuccal root, which was suspect. cbCT image confirmed that there was an untreated MB2.  A diagnosis of Acute Apical Abscess was made an retreatment steps were initiated.

The tooth was accessed and the filling material was removed from all the canals. Access to the unfilled MB 2 canal immediately resulted in purulent  drainage into the pulp chamber.

The canals were cleaned shaped and medicated with calcium hydroxide and the patient was reappointed for completion of treatment once symptoms had subsided.

Treatment was uneventful and all four canals were filled. The tooth was subsequently restored with a full Crown and recall images show evidence of good healing.

The canals were cleaned shaped and medicated with calcium hydroxide and the patient was reappointed for completion of treatment once symptoms had subsided.

Treatment was uneventful and all four canals were filled. The tooth was subsequently restored with a full Crown and recall images show evidence of good healing.

This is a situation where the endodontic treatment was initially performed in a less than acceptable manner. However,  this patient had no symptoms for almost 20 years.
Endodontists are occasionally confronted with cases in which only one of the roots has a radiolucent finding associated with with it and we are sometimes asked (for financial or other reasons)  to treat ONLY the symptomatic area or the area that appears to be associated with pathology on the radiograph. While this may allow the access to be more conservative and preserve tooth structure or the restoration, it places the endodontist in the uncomfortable position of having to rely upon a previous clinician’s work for treatment of canals to which he now must also take responsibility. Compromise of this situation happens occasionally but it leaves the retreating clinician open to risk of persistent symptoms that may have nothing to do with any treatment/retreatment that he has performed. Therefore, whenever cases are referred to me for treatment (unless the situation is exceptional), I insist upon retreating the case in its entirety so that I know that all canals have been treated as I saw best.  This may involve disassembly and re-restoration, which may push costs up to the point where an implant is considered, instead.

Occasionally, I will compromise (at the behest of the referring Dentist),   because the patient does not wish to have disassembly of the tooth performed (for financial or insurance reasons). Whether you choose to comply with this request is something that each  treating clinician must decide.

One thing is certain, performing the definitive treatment as you see it (no matter what the cost or whatever that entails) gives you the best chance for achieving the desired results.  And when it comes to retreatment, we want to give ourselves the best possible chance for success, knowing that both patients finances and tooth structure need to be “spent” wisely.

Cavity Test Aids in Proper Diagnosis

A 26 year old female patient was referred to me for consideration of the mandibular  Central Incisors   The  referring dentist had seen a periapical radiolucent area associated with the apex of these two teeth (mostly with tooth #31) and was unsure of the diagnosis.  The patient was asymptomatic and had a history of orthodontic treatment . There was no history of trauma to the area. She came in with lingual arch wire, placed to help maintain position of these orthodontically treated teeth. The crown of tooth #41 appeared to be slightly discolored, though the difference in color was small. There also appeared to be some apical resorption at the the root tip of #31 that was typical of pathology associated with teeth that had chronic periapical periodontits caused by a necrotic pulp.   Percussion palpation and periodontal tests all revealed normal findings

Pulp tests performed on all the anterior mandibular teeth showed normal responses with the exception of #41, which did not respond. This was unusual because the radiolucent finding appeared to be centered at the apex of tooth #31.

CBCT imaging showed a diffuse radiolucent apical area and bone loss encompassing  apices of both #41 and #31 on the lingual side rather than the buccal cortical plate. The bone loss seemed to be centered around tooth #31 but this was not consistent with the presence of normal pulp test responses in this tooth.

I explained my findings to the patient and suggested that a cavity test was in order so we could confirm a definitive  diagnosis of pulpal necrosis in #41.

A decision was made to remove the archwire and make access through the lingual aspect of #41 to allow us to do a cavity test. Penetration of the bur through the enamel revealed no response from the patient and the chamber was entered. The pulp was found to be necrotic and working length was easily obtained without the use of local anesthetic. Because the patient was traveling 8 hours by car (one way) to see me, we decided to complete the endodontics in one visit. The access cavity was closed with composite and I instructed the referring dentist to replace the archwire if he felt it was necessary.

The referring dentist sent a 6 month follow up radiograph (right) which shows good healing around the Endodontically treated tooth and the adjacent #31.

There is a tendency to look at a radiograph, see an associated radiolucent area and assume that the tooth adjacent to the radiolucent finding is the source of the Endodontic problem. This is not always the case and this is a good example of why it is important to perform pulp tests. Where a necrotic tooth is suspected, the cavity test is the final test to ensure the diagnosis is correct. Although this may seem a little unsettling for the patient, ensuring proper diagnosis ensures that the correct tooth is being treated.

BWs After Crowns – A Necessity?

This patient was referred to me for endodontic treatment of a mandibular right first molar. The tooth had been restored with a composite restoration which had broken on the distal aspect . This resulted in carious exposure and patient symptoms.

Clinical examination revealed positive responses to percussion and palpation and gross carious exposure of the distal pulp horns . Radiographic examination showed radiolucent findings at both apices. Pulp tests were non responsive. A diagnosis of chronic periapical periodontitis was made secondary to pulpal necrosis.

Endodontic treatment was initiated and I was very satisfied with the treatment results. The patient was immediately going over to the referrals office for core/temp crown restoration. The referring Doctor had requested a post space.

Six months later, the patient was seen for normal six month follow up to check for periapical healing. While the tooth itself had become asymptomatic, and the periapical areas were healing nicely, the patient told me that they were having difficulty flossing on the distal aspect of the tooth and that the distal gingiva was constantly sore.

Periapical radiography showed a radio-opacity on the distal aspect of the tooth . A bitewing radiograph clearly showed that cement had been left in this area during the Crown cementation six months previously. A large piece of cement was removed from the interproximal area, relieving the patient’s symptoms .

From this we can see that bitewing radiographs are an important part of assessing the final restoration to ensure not only that the margins have been fully seated but that no cement his present in the interproximal areas that could cause gingival inflammation. Therefore we can say that bitewings are a necessary part of final Crown cementation procedures.

Are You SURE its Endo?

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This patient was seen for endodontic consideration of #16. The tooth had been restored with a composite. The tooth had a crack that ran from the mesial marginal ridge distally through the composite., The patient was complaining of  Percussion, Biting and Chewing sensitivity. Cold tests were non responsive. This tooth was opposed by a full crown. (As MANY cracked teeth often ARE!)

Radiography revealed a shallow/moderate depth DO composite with no evidence of possible pulp exposure or other unusual radiolucent periapical findings consistent with pulpal necrosis.  I noted some horizontal bone loss on the bite wing. Probings were WNL.
A diagnosis of pulpal necrosis was made (possibly due to the crack) with normal periapex.  Conventional endodontic treatment was scheduled.  The distal and palatal canals were cleaned and shaped and medicated . The MB canals were extremely calcified at the midroot and required more work during a subsequent appointment. Ultimately, they were not negotiable to the terminus and  the clinical radiographic results were less than what I had hoped. However, the patient was asymptomatic after the initial appointment and I decided to obturate the case as best i could. The tooth was promptly restored with a full Crown restoration by the referring Dentist.

Approximately a year later, the referral called my office saying that the patient was having symptoms in the area and asked that I see the patient for follow up.

Examination of the crowned tooth revealed normal responses to chewing, percussion and palpation. Periapical areas appeared to be within normal limits on the radiograph and there was no sign of pathology associated with the previously short filled mesial buccal root.

The patient remarked that the symptoms appeared to be more centered on the palatal gingiva, at which time I noticed that there had been increased recession of the gingiva in that area since initial Endo treatment had been performed in my office.

Probing the palatal gingival pockets with a Perio probe elicited the exact patient current complaint. The gingival crest tissue appeared to be slightly red and tender and the patient remarked that this was the pain that she was getting when she was eating.

I suggested that this could be handled either of two ways:

(1) Referral to a Periodontist to see if a free gingival graft was a possibility to cover the exposed root (?) OR
(2) Remove the existing Crown and re-prepare the Crown margin slightly lower to encompass this receded area, while at the same time adjusting the palatal  contour of the Crown for comfort. Once a temporary Crown had been placed with a comfortable contour that deflected food away from the symptomatic area,  the Dentist could leave this in for several months to see if the gingiva stabilizes and the symptoms resolve. If so,  a new permanent Crown would be cemented to match the existing contours of the asymptomatic temporary crown.

In any case, it was clear that Endodontic retreatment was not required.

It is not uncommon for Endodontists to have patients return to their office for issues that are entirely unrelated to the previous treatment. Although Endodontists limit the practice to Endodontics, it is natural that (because we are frequently called upon to diagnose oral pain), we must know and recognize problems in all other areas of dentistry whether they be periodontal, occlusal, TMD, Orofacial, Prosthetic or Endodontic in etiology.

There is a tendency for Dentists to look at a symptomatic patient’s image on radiograph, detect an Endodontic treatment and assume the problem to be Endo related, and immediately refer the case to the Endodontist. Before you consider doing this on a previously Endo treated case, make sure to listen to the patient’s current complaint closely and you frequently will find that while the tooth may have been Endodontically treated, the patient’s current complaint has little to do with previous Endodontics.

Calcified Maxillary Lateral Proves to be a Challenge

Like the song says, sometimes you gotta “Know when to hold ’em and know when to fold ’em.”

The patient was referred for Endodontic treatment of this Maxillary lateral incisor that had a radiolucent finding at the apex . The patient had been involved in a motor vehicle accident some years ago had lost several teeth during the trauma.  The referring dentist had attempted access but could not locate a canal. Wisely, he stopped before hogging out the root or perforating the case and referred the case to me. The canal appeared to be totally calcified on a conventional film with the exception of the apical 2 or 3 mm.

Cone beam tomography also showed that there was little if any canal space except at the apical few millimeters. Nevertheless, we attempted to make Endodontic access into the tooth because we assumed that we would find our way to the apex to deal with this necrotic apical  tissue.

Unfortunately, after going very far into the tooth without being able to find the canal, I realized that further exploration of the tooth could be catastrophic. I was already at the limits of my longest Endo explorer and visibility was becoming an issue (even with a Surgical Operating Microscope and its strong light!) because the access was so small. Control of ultrasonic instruments and Munce Burs at that depth becomes critical in such narrow roots. Continuation would only result in loss of further Dentin, potentially weakening the tooth and risking perforation.

The patient was asymptomatic and we agreed to terminate the treatment at this point by obturating to the most apical extent possible and then sealing the access. If further treatment would be required, it would need to be performed surgically and efforts would need to be made to try to preserve as much of the root as possible, should that be necessary.

The question remains: How do you decide when to “Go To Surgery First” vs. attempting this type of treatment?

In most cases there IS a canal there, albeit very small. Endodontists frequently treat such cases, but there are some where, in  hindsight, an initial surgical approach may have been a better option.  As with ANY case involving surgery, Periodontal condition, Age and health of the patient, medications such as Bisphosphonates, Hygiene, attitudes toward surgical procedures, presence of an existing RPD that can be added to, how strategic the tooth is to the overall treatment plan Etc Etc ….all play a role in deciding whether a surgery may be a better option.

Virgin Cracked Molar

Virgin teeth are extremely hard when the enamel is intact . However even virgin teeth can undergo fracture to the point where the pulp becomes involved. In this case a virgin mandibular second molar had a distal fracture running through the central developmental groove to the point the pulp eventually became involved. The pulp tissue underwent necrosis and the patient began to have symptoms.

After performing the usual pulp test to determine that the pulp was non responsive, transillumination showed blockage of the light source through the central developmental groove, indicating a mesial distal crack.

All probings were within reasonable limits so we chose to perform Endodontic treatment and try to put a crown on this tooth as soon as possible to prevent further migration of the fracture. This mandibular second molar also had unusual canal anatomy in that it had a C shaped canal. C shaped canal or single canal/single conical rooted mandibular molars with fractures generally have a poor prognosis but we chose to treat this one in this case. Cleaning and shaping of the canal revealed a curtain like canal anatomy with no distinct single canals. Canals like these are extremely challenging to debride.

The endodontic filling reflects the complexity of the anatomy and the merging of the multiple anastomoses to form the C shape.

Fortunately in this case the referring dentist allowed me to place the core material and the patient was referred over to their office immediately for preparation for Crown preparation immediately after the endodontics was completed. When treatment planning such cases, it is important to arrange for restoration of this tooth as soon as possible after the endo was completed. Our office coordinates appointments with the referring dentists when we suspect this is the case of hen we  suspect deep fractures in the tooth we are treating.   Leaving the case without adequate protection , (even with relief of the occlusion) can result in catastrophic fracture in as little as a few days.
Frequently, we schedule the Endodontics in the morning and the patient is immediately seen by the dentist that afternoon for Crown preparation an appropriate temporization. This kind of service requires cooperation from the referring office and good communication between Referral and Specialist.

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