Using CBCT to Diagnose the Depth of a Cracked Tooth

 One of the many uses of CBCT is to help us determine the depth of a crack - seen on the occlusal surface of a tooth, but uncertain as to how deep it goes down the root.  Obviously the deeper the crack goes below the CEJ, the poorer the long term prognosis.

This patient was mostly asymptomatic until he recently bit into something and has had pain ever since.

Periapical film

2 Cracks seen on the MMR - with staining

CBCT shows a narrow, bony defect identifying a crack in the axial (Z) view.  The sagittal (Y) view shows the depth of the crack.  A new crown would have to go past this depth to cover the crack up.  This view helps us make a determination of the restorability of the tooth.

In this case, the crack would never be completed removed or covered up by the crown making the long term prognosis poor.  CBCT allows us to make this evaluation without having to remove the amalgam filling and chase the crack - saving the patient (and us) time and money.

Partners In Patient Care: Assisting in Treatment Planning - Cracked Teeth

The endodontists at Superstition Springs Endodontics are partners in your patient care.  One of the many ways we assist with the quality treatment of your patients in addition to endodontic diagnostics is in evaluation of restorability.  With the benefit of the dental operating microscope, we are able to excavate decay and evaluate cracks in your patient's tooth.  Every crack is unique and the extent, depth, discoloration, pulpal status, patient occlusion and parafunctional habits should all be considered in the treatment planning a tooth with a crack.

Cracks that go below the cemento-enamel junction and are not able to be completely removed when the buildup is placed or completely covered by the new crown will likely affect the long term prognosis of the tooth.  These types of cracks are best evaluated under the magnification of the microscope.  Additional tools such at staining and transilluination are also frequently used tools in the endodontist's evaluation of a crack.

Patients should be given the options and prognosis and helped to make the treatment decision that is in their best interests and meets their desires.

The following case demonstrates this process and usefulness of the microscope.

Pt is referred for endodontic evaluation/treatment.  Tooth is diagnosed with irreversible pulpitis, normal periapex and gross distal decay.  RCT recommended.

Distal decay is removed, mesial amalgam removed.  Crack identified on the mesial wall of the pulp chamber.

Further excavation reveals the extent of the mesial crack - going below the CEJ and starting to enter the root.  Patient is informed of the extent of the decay and the options: 1. Complete RCT, buildup and crown with guarded long term prognosis 2. Extraction and replacement with implant or bridge  Pt elects extraction in this case.

5 Year Recall on a Cracked Tooth

Now you are probably wondering what that title means?  As we all know, posterior teeth often get craze lines (surface cracks) in the enamel due to truama, large restorations, heavy occlusion or parafunctional habits.  When these craze lines go past the enamel and into the dentin, we refer to them as cracks.  Coronal cracks are very common in adult teeth.  Seeing a coronal crack in a tooth should prompt you to question the occlusal forces, parafunctional habits, size the existing restoration, the vitality of the tooth and then the need for coronal coverage.

This patient came to our office in early 2010.  She was reporting throbbing pain to temperature that had been bothering her for a couple of weeks.  She also reporting biting pain.  Diagnostics found #3 was normal to cold test, normal to probing, mild pain to percussion, pain to biting pressure.  DX; #3 reversible pulpitis with symptomatic apical periodontitis and cracked tooth syndrome.  We decided to treat endodontically before a crown would be placed.

Upon accessing the pulp, we found a stained crack on the mesial and smaller crack on the distal.  Pt was informed that these cracks would not be completely removed, and would affect the long term prognosis for the tooth.  The patient, understanding that the prognosis is guarded, elected to preserve the tooth as long as possible by completing the RCT and placing a crown.

RCT was completed and returned to GP for coronal coverage.

5 year recall of the tooth finds it fully functional and asymptomatic. Note the fine margins of the crown which play a key role in the success of this treatment. Some patients will elect to retain a natural tooth with a crack, understanding the guarded long term prognosis, rather than extract and replace it immediately.

Root Canal Treatment Can Save Teeth with Cracks

The following case is an example of the successful root canal treatment of a cracked tooth. Tooth #19 was diagnosed as necrotic pulp with acute apical abscess. RCT was recommended to save the tooth.

There was a large 10mm buccal probing depth, however, since the tooth was diagnosed as necrotic, this deep pocket is assumed to be endodontic rather than a true perio defect.

During treatment, a crack is found on the distal under the resin. Using a microscope, the extent of the crack is evaluated. In this particular case, the crack extended to the level of the pulpal floor. This is an important part of the evaluation of a crack, and in my opinion, can really only be done with a microscope. A crack that goes into the furcation or down into the attachment below has a poorer prognosis. Pt is informed the the crack and the potential effect on the long term prognosis of the tooth. Pt is given the choice to continue RCT and save the tooth or extract.

PreOp Film

PostOp Film

1 Year Recall

Bone has healed completely, tooth is fully functional and asymptomatic. This is successful endodontic therapy on a tooth with a crack above the crestal bone.

For more information regarding managing a teeth with a cracks, click here.

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.

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 www.facebook.com/alpharettaendo.

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

CBCT as a Tool in Endodontic Diagnosis

Cone Beam Computed Tomography (CBCT) is a valuable tool in endodontic diagnosis. The following case illustrates how CBCT provides added diagnostic information not available through traditional 2D imaging.

This patient was referred to our office today after a long week of infection and diagnostic dilemmas. Here's the story...

10 days ago with an ear ache.
9 days ago pt reports pain to chewing & closing teeth together.
8 days ago swelling began. Pt went to ER and was given zithromax, ibuprofen & tylenol #3.
7 days ago swelling increased under tongue and into face.
5 days ago, pt returned to ER where they did a CT scan and found nothing. Pt reports numbness in lip. Pt admitted to hospital and given IV clindamycin. MRI done and "something was found in lower left jaw". Pt started 300mg clindamycin.
Today, patient referred from oral surgery for endodontic consult/vitality testing. Here's how he looked.




Radiographs fairly inconclusive. #18, #19, #20, #21 all normal to percussion, probing and thermal testing.

A small crack noted on the distal marginal ridge of #18. Thermal testing once again indicates a vital pulp. Typically, we would expect a necrotic tooth to be the source of the submandibular swelling that this patient has experienced.

Since tooth #18 is responding normally to thermal testing, we decided to take a CBCT to look for more evidence of the source of infection.

This coronal slice (.25mm) shows radiolucency around the distal root #18. This image is more conclusive than the standard 2D image.

A sagittal slice through the distal root of #18 shows the lesion and its perforation of the lingual plate.

An axial view of the distal root of #18 also shows perforation to the lingual.

These CBCT slices are conclusive enough to revise the pulpal diagnosis to "partially necrotic" and recommend endodontic treatment. It appears that the distal root is necrotic and the infection is spreading through the lingual plate.

RCT initiated. Upon access, we find vital pulp tissue in the mesial canals, and necrotic pulp tissue in the distal canal.

Further removal of the distal crack finds the crack extending down the distal root, below the CEJ. Extraction is recommended.

In endodontic diagnostics, we typically classify pulpal status as:

1. Normal
2. Reversibly Inflammed
3. Irreversibly Inflammed
4. Necrotic

However, things are not always a cut an dry as that. This case illustrates that "partially necrotic" pulp is a possible classification of pulpal status.

Following removal of the tooth, the infection quickly resolved.

CBCT is an important tool for diagnostic imaging in endodontics.

Managing a Cracked Tooth

Dealing with cracked teeth can be very challenging. In the first place, there is a lot of confusion about what we are calling a cracked tooth. Craze lines, fractured cusps, split teeth and vertical root fractures are all often called "cracked" teeth. However, treatment and prognosis are different for all of these different situations.

Cracks in teeth are findings, not a diagnosis. Proper pulpal and periapical diagnosis as well as the location and extent of a crack are needed to determine a proper treatment plan. The problem with cracks in the tooth are the possibility for future bacterial penetration, which leads to inflammation and disease.

With these considerations, many teeth with cracks can be saved. Keys to saving teeth with cracks are:
1. Early detection and treatment
2. Proper endodontic diagnosis
3. Proper determination of the location and extent of a crack

The following case of a cracked tooth was recently treated at Superstition Springs Endodontics.

This patient presented with mesial decay on #14 causing discomfort. The tooth was normal to percussion, probing and no response to thermal test. DX: Necrotic pulp w/ normal periapex. A crack was noted on the distal marginal ridge. RCT recommended.

Removal of decay and access revealed the crack extending down the distal wall.

Closer examination finds that the crack ends near the level of the CEJ. Pt is informed of the crack and the prognosis is good, since the new crown will be able to cover the crack. The crack should be removed at the time of the build-up.

A main key to saving teeth with cracks is to identify the location and extent of a crack.

An upcoming Inner Space Seminar, entitled "Breakdance" will help clinicians know how to identify and classify cracks in teeth, as well as treatment plan restorative options for teeth with cracks.

Clinical Clues for Identifying Cracked/Fracture Roots

Accurate diagnosis of a cracked/fractured root is a difficult task. It is important to get it right, because the treatment for a cracked root is usually extraction. I explain to patients that there are some clinical signs that would indicate a cracked root, but they are not 100% conclusive all the time. These same clinical signs can occur in other situations as well.

The typical signs associated with a cracked/fracture root that we have previously reported:

1. J-shaped lesion or large lateral lesion

2. Deep, narrow periodontal pocket

A couple new clinical signs that I have not previously reported include:

3. Swelling in the in the marginal gingival, adjacent to the fracture

4. Failure of a swelling to resolve despite a course of antibiotics

The more of these clinical signs I see in one patient, the more confident I am that the root is cracked/fractured.

I explain to patients that the only way to know with certainty is to visualize the crack. This is most effectively done with magnification. This can either be done through an endodontic access, or through a small periodontal flap to examine the root surface. I expect that with time, CBCT will be better able to help us in the diagnosis of cracked/fractured roots. At this time, the CBCT does not appear pick up on a cracked/fractured root until the pieces of the root begin to separate.

Here is an example of a case in which several of the described clinical signs were present indicating a cracked/fractured root. Access and visualization confirmed the diagnosis of cracked root.

Pt presents with a swelling in the marginal gingiva adjacent to distal root of #19. The radiograph shows a large, lateral lesion on mesial of distal root. Patient had been taking Penicillin for several days, without resolution of the swelling. Antibiotic was changed to clindamycin to see if swelling would resolve.

Swelling did not resolve after taking clindamycin.

At this point, I am quite certain I will find a cracked root. If this were simply a perio issue or an endo issue, I would have expected it to clear up with the antibiotics.

Access into pulp chamber exposes a vertical crack/fracture on the MB root as well as the DB root.

The tooth is deemed non-restorable and extraction recommended.

If you are unsure if a tooth has a cracked/fractured root, contact your endodontist. Not all teeth can be saved, but endodontists are the specialists for saving teeth and can help you determine which ones to save.

Your Endodontist as a member of your Restorative Team

Your endodontist can be a valuable member of your restorative team. You can rely on your endodontist to support and reinforce your appropriate treatment plan.

As an endodontist, I want to see two things happen for my patients:
1. Endodontic therapy be successful
2. Patients value and retain their natural teeth

1. Endodontic therapy be successful:
Everyone knows that successful endodontic therapy requires proper coronal restoration. Without adequate restoration, even the best endodontic therapy will fail. As endodontists, we are invested in the successful treatment of the tooth, therefore, we will always encourage the patients to have their endodontically treated teeth properly restored. That means uncrowned posterior teeth and teeth with large restorations getting coronal coverage to protect them from cracks and fractures and current crowns/bridges with leaking margins/decay replaced to prevent coronal leakage. When a patient leaves my office, I make sure to let them know that they need to protect the root canal against bacterial leakage and occlusal forces. If our patients have been educated correctly, they will return to your office and ask for their new crown or bridge.

This patient came into my office today hoping for a root canal and a filling to preserve this bridge. I encouraged the patient to place a new bridge to prevent coronal leakage following endodontic treatment.

2. Patients value and retain their natural teeth:
I frequently see uncrowned posterior teeth with large restorations, craze lines & cracks. These teeth, especially in patients who are bruxers or have severe patterns of occlusal wear, are at risk of splitting the tooth. I encourage them to talk to their dentist about crowns to protect those teeth before they are damaged and become non-restorable. I hate to tell patients that they need an extraction because the tooth has split in half.




The general dentist has the primary responsibility for treatment planning. Your endodontist can play an important part of your restorative team by helping to educate your patients on the importance of proper restoration following endodontic treatment and the importance of proper restoration to prevent cracks/fractures.