Modern Bioceramics in Endodontics

Porcelains have been at the heart of esthetic dentistry since the 1960's with a broad assumption that they are bioinert - not eliciting a reaction from the tissues around them.

Without diving too deep in the science of biomaterials, a bioactive material is one that intentionally elicits a response from adjacent tissues and biocompatability refers to a material that does not cause harm to adjacent tissues.  Biocompatibility is not absolute(1) and requires evaluation of a material's interaction with tissues over time.  In other words, more complex than this discussion.

Advances in dental ceramics have continued to evolve into what we now call bioceramics. These materials include hydroxyapetitie, bioactive glass and calcium silicates.(2)

One of the earliest bioceramics used in Endodontics was Mineral Trioxide Aggregate - a silicate cement.  This bioactive and biocompatible material was unlike anything we had seen before in endodontics.  It could be used in a moist environment - actually requiring moisture to set up, did not seem to irritate the adjacent tissues and bone would form right up against it!  It did not take long for this  material to be used for root repair (additional example) & apicoectomy retrofills.

With the biocompatible success of this material, and seeing that it clinically created good seal, it wasn't long before we began using this bioceramic for direct pulp capping and using this material to replace traditional apexification/apexogenesis a new type of procedures known as pulpal regeneration.

 

One of the biggest challenges with the use of MTA was the grey discoloration of the tooth.  The grey staining of the tooth created esthetic challenges in the anterior.  In effort to address this complication,  Tulsa Dentsply developed a white MTA by reducing the aluminoferrite content.

The bioceramic line up has grown since the development of white MTA with additional calcium silicate cement products from Septodont, Brasseler, Avalon Biomed etc.  These modern bioceramic materials claim to have the impressive properties of:

• Osteogenicity
• Chemically bond to dentin
• Antibacterial (pH>12)
• Hydrophilic
• Hydroxyapatite producing
• No shrinkage
• Good working/setting time
• Easy delivery systems

Every one of these properties make these materials ideal for use in Endodontics. By adjusting the thickness of the material for different applications, we now use these materials as endodontic sealer, root repair material, root end filling materials, pulp regenerative procedures.

With improved esthetics, these modern bioceramics are now the standard of care for pulpal regenerative procedures.

The modern bioceramic materials, with these amazing bioactive and biocompatible properties, are opening up new restorative options when it comes to carious lesions on vital teeth.  

Bioceramics can be placed directly against the pulpal tissue and maintain vitality of the pulp.  This means that direct and indirect pulp capping with CaOH is out and the new bioceramics are in. This new approach includes a major paradigm shift when it comes to pulp capping procedures.  Previously, we attempted to minimize any pulpal exposure.  Now, with the bioactive and biocompatible properties of bioceramics, the goal is complete removal of caries and infected pulpal tissue (even complete pulpotomy if needed) and proper seal with a bioceramic and immediate bonded coronal restoration.  This procedure is known as Vital Pulp Therapy (VPT) and should be considered in your restorative practice in the place of direct and indirect pulp capping.  In an upcoming post, we'll share the steps and cases to help you apply this in your restorative practice.

In a 2021 meta analysis (3) on the prognosis of vital pulp therapy on permanent teeth, when MTA or other bioceramics were used as a capping material they were found to be successful 93% of the time.  This means that VPT should be an option for your treatment of carious teeth - prior to endodontic treatment.

Stay tuned for more info and clinical tips on Vital Pulp Therapy.

Sources:

1. Wataha JC. Principles of biocompatibility for dental practitioners. J Prosthet Dent. 2001 Aug;86(2):203-9. doi: 10.1067/mpr.2001.117056. PMID: 11514810.

2. Dong X, Xu, X. Bioceramics in Endodontics, Updates and Future Perspectives.  Bioengineering. 2023 Mar13;10(3):354.

3. Prognosis of Vital Pulp Therapy on Permanent Dentition: A Systematic Review and Meta-analysis of Randomized Controlled Trials Sabeti, Mohammad et al. Journal of Endodontics, Volume 47, Issue 11, 1683 - 1695

Preventing Root Canal Perforation by Case Selection

This patient came to Superstition Springs Endodontics in June 2009.  Her general dentist had started RCT on #3 but was unable to locate the MB canal(s).  A perforation was made during the efforts to find the MB canals.  We have taught the generalists in our community that the most successful and fulfilling way to practice endodontics depends upon careful case selection.  Proper case evaluation can:

1.  prevent lost chair time without reimbursement
2.  prevent loss in patient confidence
3.  prevent clinician frustration

The Endodontic Case Assessment Form from the AAE, can help clinicians determine the difficulty level of treatment - before therapy is started. This is how this case should have been classified - prior to starting treatment. 

 

 

 The treatment for this tooth was RCT completion and repair of the iatrogenic damage using Mineral Trioxide Aggregate (MTA).

Fortunately, with good repair materials, the prognosis for a tooth like this is still good.  A 7 year recall finds the tooth in full function and asymptomatic.

However, proper case selection will make your practice of endodontics more fulfilling, less stressful and ultimately, more successful.

Successful Endodontics in Your General Practice

Successful endodontic treatment in the general dentist's office is based upon proper case selection.

Proper case selection will allow endodontics to be a profitable, enjoyable procedure and provide a valuable service to your patients that will build your practice.

Failure to perform proper case selection will result in:

1. Frustration

2. Loss of patient confidence

3. Loss of practice revenue

4. Additional costs incurred with retreatment or repair of iatrogenic damage

The American Association of Endodontists has prepared an assessment form to help clinicians evaluate the level of difficulty associated with endodontic treatment to help the clinician decide when to refer. (click here)

To summarize this assessment form, here's a breakdown of the type of cases that are considered minimal, moderate and high difficulty level.

MINIMAL DIFFICULTY

1. Pt is healthy, cooperative, minimal pain and/or swelling

2. Diagnostics are clear and pulpal/peripaical diagnosis made without complication

3. Tooth is easily accessible for treatment. (anteriors/premolars w/ slight inclination or rotation)

4. Canal is open, not calcified, mature apex, no resorption

5. No previous RCT

6. Root has slight curvature

7. Periodontium is healthy

MODERATE DIFFICULTY

1. Pt has minimal health issues, anxious - but cooperative, moderate pain and/or swelling

2. Diagnostics requiring additional evaluation (sinuses, TMD, electric pulp testing on calcified teeth)

3. Tooth accessibility is difficult - 1st molars, moderate inclination, rotation, crown, bridge, extensive decay

4. Canal is reduced in size, pulp stones, wide apex

5. Prior RCT without complication

6. Root has moderate curvature

7. Moderate periodontal disease

HIGH DIFFICULTY

1. Complex health issues, difficulty cooperating, severe pain and/or swelling

2. Diagnostics difficult - confusing complex signs & symptoms, chronic oro-facial pain

3. Tooth accessibility is difficult - 2nd & 3rd molars, severe inclination, severe rotation, crown/bridges with alignment irregularities

4. Canal is calcified (not visible), S or C-shaped, canal divides in middle or apical thirds, additional roots (3 rooted bicuspid), apex is open

5. Prior RCT with complication

6. Root has severe curvature

7.History of traumatic injury (avulsion, horizontal fracture, luxation)

Each clinician must evaluate the difficulty level and select cases that match his/her skill level and cases for which they have adequate instrumentation.  Pick cases that you can do in a timely manner, without complications.  As you become more and more comfortable, select slightly more difficult cases to challenge you, always being aware of that some cases are better managed under the microscope and with the aid of CBCT.

 

 The following case demonstrates the benefit of proper case selection.

Root Canal on a C-shaped, 2nd molar, through a crown with mild angulation and calcified canals makes this root canal a "HIGH DIFFICULTY" level.  The clinician performing this treatment had challenges due to these issues.  Access was difficult, interpreting the c-shaped canal was difficult and C-shaped canal all led to the mesial perforation.  The calcified canals also made it difficult to instrument/fill to the apex.  The perforation was improperly managed by sealing with gutta percha and patient was not informed of the complication.

CBCT view of the issues

Retreatment completed with MTA repair of mesial perforation.

  Prognosis: Fair

Proper case selection also helps you to build relationships with your endodontist.  When you have a good working relationship with your endodontist, you can rely on him/her to help you advance your endodontic skills and experience as well as help in difficult case management.

Microscopes & Management of Root Canal Perforation

As discussed in Dr. Justin Parente's previous post, dental operating microscopes can prevent procedural error in endodontic treatment.

There are those who may debate this, but in my opinion, microscopes are the standard of care in endodontics. Molar endodontics should be done using a microscope. In our practice, we use microscopes on every case. Perforations happen, missed canals happen, but with a microscope (and other advanced imaging systems - but that is another post) they are much less likely to occur.

The following case is that of a root perforation, it's microscopic retreatment, repair using MTA and the 6 month recall showing healing.

This patient was referred to Superstition Springs Endodontics with the complaint of "constant pain on lower right". Our diagnostics found #30 with Prior RCT and symptomatic apical periodontitis (SAP). He reports that this root canal was done 1.5 yrs earlier by a general dentist.
As you can see in the radiograph, there is a large pa lesion on the distal root and a radiolucency in the furcation area - likely caused by furcal perforation.
We discussed options and recommended retreatment with probable perforation repair in the pulpal floor.

Upon access, we found a furcal perforation that had been covered with resin buildup material.

RCT retreatment was completed. By using a microscope, we were able to locate a 4th canal that had previously been left untreated in the distal root. We also repaired the pulpal floor perforation using MTA.

At 6 month recall, you can see that the periapical lesion has healed very nicely. The bone loss in the furcation area has also improved. The patient is functioning on this tooth and is asymptomatic. He occasionally reports some swelling adjacent to the tooth, but upon our clinical exam today, probings are normal and there is no sign of irritation or infection.

Prevention of root perforation is always better for the long term prognosis than perforation repair. Use of magnification and lots of light (microscope), understanding pulp & canal anatomy, proper use of high & slow handpieces and ultrasonics, recognizing buildup material from dentin of the pulpal floor are all important factors to help prevent root perforation. With that said, if perforation occurs, the patient should be informed and the perforation should be repaired immediately with MTA. Proper management following root perforation can allow the tooth to be retained. Endodontists are specialists in saving teeth.

The Dental Operating Microscope Prevents Procedural Errors in Challenging Teeth

In case you are a new reader, it merits repeating that the dental operating microscope is the most valuable tool available for providing endodontic care.  The light and magnification provided are critical to success.  With this post, I will present two recent cases where two different clinicians had difficulty locating canal anatomy and perforated the root structure.  Each case was originally treated by a general dentist within the last year or two. With the use of a dental operating microscope, I was able to locate the missed canals and repair the perforations.  Hopefully, our clinician readers who are not microscope trained will become motivated to invest in one.

Case 1

This patient described an on and off awareness of her tooth since root canal treatment by her general dentist.  Her symptoms began to worsen, and she noticed a bump on the gums that drained.  Her general dentist had admitted to difficulty locating a challenging ML canal.

Preoperative Distal Shift
Note the ML canal is obturated a few millimeters below the orifice.

Preoperative Straight
Note the furcation radiolucency and absence of apical problems.

There was no clinical sign of swelling or of a sinus tract at our appointment.  The tooth was tender to percussion and uncomfortable to palpation in the furcation area.  Probing depths were 2-3mm with some bleeding and serous drainage on probing in the furcation area on the buccal.

A diagnosis of previous root canal treatment with a chronic furcation abscess was made.  I discussed the findings and treatment options at length with the patient.  When a perforation exists for a long time and then becomes infected, our success rate with retreatment drops by some indeterminate margin, and the treatment was not without risk.  The patient opted to take a chance on saving her tooth.

Upon access, purulent drainage was found pushing up from the gutta percha in ML area.

Upon removal of the gutta percha, a perforation was found that drained. 

After irrigating the perforation site with saline, and drying, the ML canal was located lingual to where the previous clinician had been looking.  It was high on the wall.

I was surprised to find the ML canal to not merge with the MB canal.

The location of ML was confirmed.  (ML not MB2!)

After two weeks of calcium hydroxide treatment, the patient returned symptom free and with improvement in the periodontal health.  You can see on our post op radiographs just how large the perforation was.

At a second visit two weeks later, the canal was obturated and the perforation repaired with MTA.
While the MTA extruded into the furcation is not ideal, the area should continue to heal.

Post operative image distal shift.

At a follow up visit, the patient remained symptom free and the periodontal health continued to look good.  The extruded MTA does not appear to have affected the outcome, which is consistent with the findings of others. For example, see this case of a large furcation perforation repair by Dr. Hales: http://www.theendoblog.com/2008/06/herodontics.html

Case 2

This patient initially presented with a chief complaint of minor soreness to bite forces and an intermittent dull pressure ache that she described as emanating from between the teeth #13 and #14.  Her symptoms were described as unchanged with root canal treatment by her general dentist within the last six months.  She described an improvement in symptoms when flossing and flushing between her teeth with Peridex.

Preoperative image.

The tooth was slightly tender to bite forces and percussion, but there was again no signs of swelling or a sinus tract. The probing depths were 2-3mm with a 7mm pocket on the MB and a 6mm pocket on the DB.  Because of the bilateral probing and bone loss, and the symptoms unchanged with root canal treatment, I recommended a periodontal evaluation.  I knew that there was an untreated MB2, but the periodontal symptoms did not match up.  After periodontal treatment, the pocket on the distal resolved, and there was a short-term improvement in symptoms, but they soon returned.  At this point, I was suspicious of a perforation.  A CBCT would certainly help confirm the diagnosis and be of value, but a decision was made to access and investigate.

Upon access, gutta percha was found in the location of the MB2.  Beneath, a perforation was found, just as in the previous case.

A file was inserted and a radiograph taken to confirm the perforation location.

Here you can see a 6 file entering the true MB2 canal.  It was located angling toward the mesial and buccal from the perforation.

The canal opened up a little.

A file inserted confirms the MB2 location.

Now, the MB2 can clearly be visualized after proper orifice shaping.

A gutta percha cone was inserted into the canal, and the others blocked with cotton while MTA was used to repair the perforation.

At the first visit, the patient was made aware of a fracture from the mesial to the distal that dramatically decreased the prognosis for the tooth.   After the first visit, the patient's symptoms resolved, and she could chew comfortably.  A case could be made to have the tooth immediately extracted, but the patient opted to finish the treatment even with the uncertainty involved.

Unfortunately, this tooth also exhibited a fracture across the floor of the pulp chamber.  These fractures are  very bad for the longevity of the tooth. 

Post operative radiograph

In each of these cases, it is clear from the preoperative radiographs, that the clinicians who originally treated these teeth had good command over the processes of instrumentation and obturation.  Both cases are instrumented to length (with the exception of the DB of #14), and appear well obturated with Thermafil carriers.  Both clinicians were aware of the missed anatomy, but could not locate the ML and MB2 canals respectively.  They were certainly difficult ones to find; they were not immediately obvious upon access, and while I do have extra training in endodontics, the microscope is what enabled these teeth to be saved.  The long-term prognosis of either tooth is not great, especially the fractured #14, which could fail in the short-term, but the patient's were well educated and appreciate the risks involved.  The patient with tooth #14 is now prepared for the eventuality of a dental implant in that site.

The success of perforation repairs depends on many factors, such as the time since perforation, the location within in the tooth, the size of the perforation, and the materials used for repair.  The smaller and more recent the perforation, the better the chance of success.  The farther apical the perforation, the generally better success with repair, as long as the true canal path can be recaptured.  Furcation perforations are the easiest to access for repair, and have the best surrounding tooth structure.  Perforations in the gingival attachment level have a decreased prognosis due to difficulty controlling materials and the increased risk of a periodontal defect.  In the Toronto studies (Friedman 2004), a prospective longitudinal study of the success of endodontic retreatment, of the 8 cases, roughly half of the retreatments with perforation exhibited healing.  However, the materials used for repair in this this study were glass ionomers.  In another study, 16 out of 16 cases repaired with MTA exhibited healing at a minimum of 1 year (Torabinejad 2004).

For tips on the placement of MTA, see this other post by Dr. Hales: http://www.theendoblog.com/2008/04/placement-of-mta.html

Example of a case of perforation repair in the lateral gingival attachment.  I used MTA for this case, and the perforation was repaired non-surgically.  The patient's restorative dentist used glass ionomer as a restoration on top. A case for a different treatment plan involving crown lengthening could be made.

All three teeth in this posted here I consider to have guarded long-term prognosis.  However, all three patients continue to chew and function in the absence of disease.  If you have any questions or input, please let us know.

Any suggestions for future topics or posts are also welcome!



Farzaneh M, Abitbol S, Friedman S. Treatment Outcome in Endodontics: The Toronto Study.  Phases 1 and 2: Orthograde Retreatment. J Endod. 2004;30: 627-33.

Main C, Mirzayan N, Shabahang S, Torabinejad M. Repair of root perforations using mineral trioxide aggregate: a long-term study.  J Endod. 2004;30: 80-83.

Re-Apicoectomy.

Occasionally, we see cases that have had previous treatment, retreatment, and apicoectomy, often times many decades ago, and now require intervention.  The prognosis on these cases is often guarded at best, and it is great that we have dental implants as an option.  If a tooth has a fractured root or is in poor restorative or periodontal condition, I generally recommend a dental implant.

However, there are some select cases, and select patients, where there are some alternatives.  I have a few such cases where I have elected to retreat a case with previous apicoectomy, and have had success without redoing the apicoectomy.  This is usually necessary where the entire canal system or chamber is contaminated, or there are missed canals that can be addressed.  In fact, a missed canals, or a leaking restoration are the most common reasons for apicoectomy failure.  I will save those cases for a future post, and instead show a couple cases where it was decided to "re-apico" the tooth.

This first patient suffered a traumatic sports injury 30 years ago to her anterior teeth.  The original root canal treatment was done at that time.  The teeth had apicoectomies within a few years.  The crowns on the teeth were recently redone, and a sinus tract was noticed soon after.  As an aside, the appearance of apical pathology on a previously treated tooth only following a new restoration is a common trend.  The most likely explanation is a lack of proper isolation during restorative care and a lack of seal in an old root canal treatment.  

There was heavy amalgam tatooing of the buccal mucosa, but the patient was happy with the esthetics of her new crowns after many years of having crowns she considered ugly.  I discussed treatment options at length, and ultimately referred her to a periodontist for implant consult and to learn about the alternative treatment.  After discussing the option of implants with her periodontist, she came back to me to take a chance on redoing the apicoectomy.  The sinus tract was only associated with #9, but upon access, a granuloma perforating the B plate of #8 was noted, and a decision was made to treat both teeth.

Preop #9

Preop #8

Intraoperative, note the extreme bevels already present.
A submarginal scalloped rectangular flap was selected due to an abundance of attached gingiva.  (pic is flipped)

Post op.  MTA retrofil.

1 month recall, no sinus tract.

The 6 month recall will be coming up soon.  

Case Two is similar and more recent.  This was an extremely challenging case.

This patient presented with two sinus tracts, each tracing to #9 and #10.  The crowns on 8-9 and 10 were all recently redone within the past three months.  The post on #9 is out the end, and crown to root ratio is poor.  I recommended ideally extracting #9.  A case could be made to retreat #10, and that would be my usual preference.  The patient understandably was averse to extracting #9, and so an alternate plan of apicoectomy of both #9 and #10 was suggested.  Tooth #9 was already splinted to #8, so mobility is unlikely.  I likened the desired final result to a cantilever bridge, with a little bit of support.  I cautioned the patient that the prognosis was guarded at best, and the patient again wished to proceed with treatment.  

Preop radiograph.

Dual sinus tract tracing.

Upon access, a complete lack of buccal cortical plate on #9 was noted, and is obviously not ideal.  (pic is flipped)
  A papilla-base preservation flap was selected due to a lack of attached gingiva for a  submarginal.
Hemostasis was a major challenge with this patient.

I was able to resect some of the post, retroprep the GP on the palatal aspect of it, and pack it with MTA.
(flipped pic)  I also apologize, the color balance is off on some of these last few photos.

The MTA retrofil on #10. (flipped pic)

Closure with interrupted sutures. (flipped pic)

Post op radiograph.

I was very pleased with the final result of this case.  Only time will tell if we can have sustained success.  I'll be recalling this case is the coming months.

These two cases turned out as well as I could have expected, but I always appreciate any feedback. I always have more to learn about endodontic surgery, since my preferred approach is retreatment for an overwhelming majority of cases, and I don't have some of the experience in surgery that some other clinicians have.  If you would have selected a different flap design, let me know! I'm open to suggestions.

Both cases posted here could certainly have been treatment planned as dental implants.  However, both patients were in the unique situation of very recently having invested in new crowns.  With careful patient selection and expectation management, I believe we can offer patients these types of treatments to preserve their natural teeth, even if for only for a few more years.  

For more unique cases and content, check out our facebook page, www.facebook.com/alpharettaendo.

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.

PreOp

Post-op

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.

PreOp

Post-Op

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.

PreOp

PostOp

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, http://www.facebook.com/pages/Alpharetta-Endodontics/137382942943581 . 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.