Research Update: Use of MTA for Direct Pulp Capping

In a recent post, we have discussed the use of MTA as a pulp capping agent.

A recent article by Yasuda, Ogawa, Arakawa, Kadowaki and Saito entitled "The Effect of Mineral Trioxide Aggregate on the Mineralization Ability of Rat Dental Pulp Cells: An In Vitro Study" may shed some light on the reasons MTA may be more effective than calcium hydroxide for direct pulp capping.

Direct pulp capping is an effort to maintain the vitality of a dental pulp following exposure during excavation and thereby avoid endodontic therapy. The formation of a dentinal bridge over the exposed pulp surface is the goal while maintaining pulpal vitality.

Conventional pulp capping treatment included medicating the exposed pulp with calcium hydroxide (ie. Dycal) prior to restoration. Calcium hydroxide is known to cause an inflammatory reaction of the dental pulp. Appication of adhesive resins has also been attempted. Incomplete dentinal bridges has been found with a lack of published long term clinical results.

It has been reported that MTA induces the formation of dentinal bridging with little or no inflammation. MTA is known for it's biocompatibility and lack of cytotoxicity. Tani-Ishii et. al. reported that MTA upregulated the expression of type I collagen and osteocalcin in osteoblasts.

Bone morphogenic proteins (BMP's) are crucial to bone and collagen formation. BMP-2 and it's receptor are expressed in the dental pulp. BMP-2 has been shown to accelerate the differentiation of human pulp cells into odontoblasts. This study hypothesized that BMP-2 is involved in the MTA induced mineralization.

This study found that MTA significantly stimulated mineralization (in rat dental pulp cells) by 60% compared to the controls. MTA and Dycal both significantly upregulated by 2-fold the level of BMP-2 mRNA compared with the controls. MTA increased the BMP-2 protein production by 40% while Dycal significantly reduced it. The authors suggest that BMP-2 may play an important role in mineralization stimulated by MTA.

MTA has shown promise as a direct pulp capping agent which may improve the success of direct pulp capping over convention calcium hydroxide techniques.

Sources:
Yasuda, Ogawa, Arakawa, Kadowaki, Saito. "The Effect of Mineral Trioxide Aggregate on the Mineralization Ability of Rat Dental Pulp Cells: An In Vitro Study". JOE 2008; 34:1057-1060.

Tani-Ishii, Hamad, Watanabe, Tujimoto, Teranaka, Umemoto. "Expression of Bone Extracellular Matrix Proteins on Osteoblast Cells in the Presence of Mineral Trioxide". JOE 2007; 33:836-839.

Preventing Coronal Leakage in A Pediatric Patient After Endodontic Treatment

This 10 year old patient had a carious pulp exposure on tooth #19. The tooth was diagnosed with a reversible pulpitis and normal periapex. Upon excavation, a carious pulpal exposure occurred. With root developement completed and a cooperative patient, endodontic treatment was completed.
In a case like this, knowing that she will not have a permanent crown for about 8 more years, I become concerned about preventing coronal leakage. In an effort to create another barrier to prevent coronal leakage, I use MTA to seal the canal orifaces.

MTA (Mineral Trioxide Aggregate) is placed into the canal oriface. The MTA will provide a better coronal seal than a bonded restoration alone. The gray color of the MTA makes it easy to remove if the GP ever needs to place a post. Patient's parents are informed of the risk of coronal leakage during the adolescent years and proper preventive care is encouraged to protect the investment made in the tooth.

Patient is referred back to general dentist for comprehensive care. This may include a provisional type crown which will be monitored closely over time.

Endodontic Surgery in the Esthetic Zone

One of the big challenges with dental implants is working in the esthetic zone (anterior maxilla). Crestal bone loss, which often occurs with dental implants, can lead to loss of gingival papilla. Loss of the papilla will lead to dark triangles and long clinical crowns. In an areas as esthetically sensitive as the maxillary anterior, loss of crestal bone can become a big challenge.

Endodontic microsurgery may allow you to save a natural tooth and preserve the crestal bone. Since endodontic surgery is an advanced technique taught in specialty residencies, many dentists are not as familiar with the possibilities of endodontic surgery. In addition, the advancement of surgical techniques and instruments have completely changed the endodontic surgical technique and it's outcomes.

The following case is an example of endodontic microsurgery.

Pt presents with a draining sinus tract on #10. A periapical radiolucency is noted. While pt reports the RCT was completed "eons ago", the post and crown are only a year old. The silver cone obturation, while past the apex, has served this patient well for many years. Options were discussed and the patient elected to have endodontic surgery.

An Ochsenbein-Luebke flap was used to help preserve the marginal gingiva. The silver point was removed and the canal was retrofilled with MTA (Mineral Trioxide Aggregate).

Post-op radiograph


3 month recall finds complete function, significant radiographic healing & preservation of the crestal bone.

Getting the Stain Out!

Following trauma, tooth discoloration is very common. The discoloration comes from the bleeding inside the pulpal chamber. The dentin becomes stained as the blood gets into the dentinal tubules and trapped in the pulp horns. The first step in restoring the natural color to the tooth is good endodontic therapy with adequate removal of the stained facial dentin and complete removal of the pulp horns. If the natural tooth color is not restored with this procedure, then the additional treatment of non-vital internal bleaching is indicated.

A common error is incomplete removal of the pulpal horns due to a small apically placed access. Care must be taken to remove stained dentin and pulpal horns while trying to preserve maximum tooth structure.

The following case shows how to "get the stain out".

Tooth #9 & #10 sustained traumatic injury.

Note the discoloration on #9.

After opening the access, staining can be seen in #9. #10 looks normal.


A round bur is used to remove the stain from the facial surface of the pulp chamber. Careful examination with magnification reveals remaining stain in pulp horns. The access is carefully refined to remove stain from pulp horns while keeping access as conservative as possible.


Following removal of rubber dam, the change in coloration is noted. Patient is informed that the tooth is dehydrated and will continue to change color until rehydration is complete. At that time, evaluation can be made if additional internal bleaching procedures will be needed.

Obturation completed.

Adequate endodontic therapy alone will often resolve the patient's esthetic concerns. Non-vital bleaching is a good adjunct for teeth requiring additional whitening.

Another Abscess Healed

This patient presented for treatment on #19. Tooth was diagnosed as necrotic with symptomatic apical periodontitis. Endodontic therapy recommended.


RCT completed. 6 month recall shows complete healing of the apical lesion. My concern is the distal leakage under the bridge. If this bridge is not replaced, the abscess will return. Some would then consider that endodontic failure, when in reality it would be a restorative failure.

The Split Tooth - A Cracked Tooth Gone Bad

Talking about cracked teeth is sometimes confusing. There are several types of cracked teeth. The treatment and prognosis of a cracked tooth depends on the type, location & severity of the crack.

Types of cracked teeth include: craze lines, fractured cusps, cracked tooth (restorable type and non-restorable type), split tooth & vertical root fracture.

A split tooth is caused by a cracked tooth that has gone untreated over a period of time. The tooth is literally split into two pieces by a crack that runs through the tooth. A tooth can be split mesio-distally or linguo-buccally. The crack of a split tooth includes damage to the root itself. The crack of a split tooth can be seen crossing the floor of the pulpal chamber. This is a sure sign of a non-restorable tooth.

The following case is an example of a split tooth.

This patient presented for endodontic therapy. #15 had a small occlusal amalgam. The tooth is diagnosed as necrotic with symptomatic apical periodontitis.

Close examination of the occlusal surface shows a stained crack on the mesial & distal marginal ridges. You can see that the lingual and buccal surfaces of the tooth have been flexing for an extended period of time. The clinical appearance of this tooth strongly suggests a split tooth.
In this case, the patient was informed of the probable non-restorability of this tooth.

Removal of the amalgam shows the connection between the MMR & DMR cracks. The argument for a split tooth becomes even stronger.

After access into the pulpal chamber, the cracks can be traced down the mesial and distal walls and then connecting across the pulpal floor. The diagnosis of split tooth is now confirmed.

Just for fun, transillumination is used to show the cracks.

Tooth was referred for extraction.

Source: AAE publication

Root Perforation causing Tooth Loss

This patient came to our office for evaluation of tooth #3. He reported having a recent root canal and crown done by a general dentist. Since the time the work was completed, he was experiencing "burning & itching in the gums around that tooth". The patient was concerned that he was having an allergic reaction to the cement or materials of the crown.

Our examination found #3 sensitive to palpation, moderately sensitive to percussion. (Adjacent teeth WNL) The radiopacent material in the furcation area of the tooth was noted.

Retreatment was initiated to evaluate the area.


The crown was first removed. Upon first look, there appears to be mesial decay still present and an obvious void between the tooth and the post/core material.

Additional removal of the buildup material shows a surprise underneath.

It become obvious that the distal wall of the MB canal has been perforated.

At this point, we can understand where the symptoms have been coming from. An attempt could be made to try and repair this defect (with MTA), however, the long term prognosis would be guarded to poor. Considering the the cost of initial treatment, the cost of retreatment which would then require post & build-up and new crown, this patient elected to extract the tooth.

This then becomes an appropriate time to replace this missing tooth with an implant or bridge. I recommended an implant consultation.

Endodontic treatment did not fail on this patient. The treating doctor failed to put his patient's best interest first and failed to inform the patient of the treatment complication (perforation) that occurred during treatment.

In a case like this, the patient referred himself to our office for evaluation. Had his dentist properly evaluated the case difficulty and referred him to an endodontist for treatment, this tooth would likely not have been lost.

This is not endodontic failure. This is failure to do good endodontics. This failure to do quality endodontics may be part of the reason that some clinicians are questioning the success of endodontic treatment.

Root Canal or Implant?

The latest version of Inside Dentistry (July/August 2008, volume 4, number 7) has a very interesting cover story by Allison M. DiMatteo BA, MPS. As an endodontist, I have been watching this debate develop for quite some time. I think it is important to determine what is behind this effort to pit one dental specialty against another.

This particular article seeks the opinion of endodontists and periodontists alike. All sides agree that implants are a great way to replace missing teeth. There is consensus that there is value to retaining natural teeth. The disagreement seems to come from the debate about when to remove a tooth in order to place an implant.

There are some who argue that implants are more successful than endodontically treated teeth. This is despite the evidence that shows that implants and endodontically treated teeth have similar, almost identical success rates.

Richard Mounce DDS, an endodontist, points out that the only controversy between endodontics and implants is "primarily economic and more artificially manufactured than exists in reality...There are clear indications for endodontic therapy and clear indications for implant therapy. Rarely are these treatment options so evenly weighted that when considered side by side (as to their advantages and disadvantages) that there should be a 'competition' or 'controversy', most especially when the patient's interest is put first".

According to Gregori M. Kurtzman DDS, "as a general rule, it is better to save a tooth...if you can". Restorability is the key factor in determining when a tooth needs to be removed. Ability to get a good margin, not violate biological width, cracks, strength of furcation, crown:root ratio etc. are all important factors in determining the restorability of the tooth. An endodontically treated tooth with a poor restoration, will generally not have long term success.

However in the same article, Dr. Kurtzman goes on to questions the success rates of endodontic surgery, and even the value of endodontic retreatment. Dr. Kurtzman points out that the financial investment into retreatment, like all treatment options which does not have 100% success rate, may be better made in a more predictable treatment of an implant.
That argument shows lack of understanding and appreciation for modern microscopic endodontic therapy.

I routinely recommend implant therapy for patients. What concerns me as a specialist is to see the marketing techniques and lack of proper endodontic evaluation during the treatment planning of implant cases. All of our mailboxes are full of marketing journals filled with clinical cases of implant placement.

Here is an example of two cases in the same issue of Inside Dentistry p.104-108.

This case is described as a "peri-apically involved maxillary incisor resulting from a failed root canal." Treatment options were reviewed and informed consent was obtained. Based on the patient's desire to reduce trauma and treatment time, it was decided to perform immediate implant placement. First of all, failed root canal is not an accurate diagnosis. The radiograph does not show the peri-apex. As best as we can tell the periodontal ligament looks fairly normal at the periapex. Was retreatment an option discussed? If it was, would it not be considered "less truamatic" than extraction and immediate implant placement? Not to mention the ability of a natural tooth to retain the crestal bone levels. Unless this tooth has a vertical fracture, of which there is no evidence, endodontic retreatment is a better option.

Another case from the same article shows a 27 year old female with a "symptomatic maxillary left lateral incisor with a history of endotherapy with a core build-up and crown". Active infection was noted with perilous fistula and exudate at the gingival margin. The prognosis of this tooth was deemed "hopeless".

Again, the endodontic evaluation of this tooth is incomplete. The anterior "bite-wing" type film certainly shows a normal crestal bone level, however, it is impossible to evaluate the endodontic therapy and is not a sufficient pretreatment radiograph. The conclusion that this tooth has a "hopeless" is premature.

Inadequate endodontic evaluation seems to be commonplace in many of the published clinical cases and those marketing dental implants. As mentioned above, there should be little controversy regarding endodontics and implants. Our specialties should not be pitted against one another, but should work together to meet the needs of our patients.

Sources:

DiMatteo, A. "Making the Right Move: Planning Your Clinical Strategy", Inside Dentistry, July/August 2008. p122-133.

Malek, M. "Done in a Day: Immediate Tooth Replacement with Definitive Prosthesis", Inside Dentistry, July/August 2008. p104-108.

Diagnosing Root Fractures - continued

As mentioned in the last post, in most cases, I prefer to verify a fracture before extraction. This is time consuming and not very profitable, but I believe it is in the patient's best interest.

However, there are some cases where it is reasonable to call a root fractured without seeing the fracture. Here is an example.

This 80 year old patient had this root canal done many years ago. She presented today with redness and swelling/sinus tract on the buccal surface. Examination finds #4 with normal pocket depths, lateral and apical radiolucency & class II mobility.

All of these clinical findings (normal probings, lateral lucency, mobility, sinus tract at the midroot) point to the probability of a root fracture at the level of the post rather than an endodontic abscess or periodontal abscess.

I recommended extraction due to fractured root.

Diagnosing Root Fractures

Diagnosis of a vertical root fracture is very difficult. It sometimes frustrates me to see how quickly some people diagnose a root fracture. I tell my patients that I like to rule everything else out before I make that assumption. I say assumption, because unless you can visualize the root fracture, you are making an assumption.

There are some clinical signs that can be associated with a vertical root fracture, however, they are not 100% diagnostic of a vertical root fracture.

For example, a long narrow periodontal pocket is often associated with a vertical root fracture. The periodontal attachment breaks down along the fracture line, creating this defect. However this same type of narrow periodontal defect can also be caused by an abscess draining through the periodontal ligament.



A j-shaped lesion is often associated with vertical root fractures. However, not all j-shaped lesions are fractured roots.

In this case there were no fractures found. Complete resolution of these lesions is expected.







If visualization of a vertical root fracture is the most accurate way to diagnose a root fracture, how is that to be done?


Visualization of a fracture is best done using a microscope. A microscope with a light source will allow you to see fractures during endodontic treatment.

A microscope will allow you to determine if a crack goes down past the CEJ and into the root
or if it crosses the pulpal floor.

Visualizing a crack running across the pulpal floor of the tooth is (on left) is a 100% accurate diagnosis. This tooth must be extracted.










This is another example of a crack running along the floor of the pulp chamber from the MB root to the Palatal root of a Mx first molar.












In most cases, I prefer to verify a fracture before extraction. This is time consuming and not very profitable, but I believe it is in the patient's best interest. This is also the course I would take if it were my tooth.

A Good Day

These are my cases from Monday. This is how I like my cases to look. Nice open canals, obturation to 0.5mm of radiographic apex & small puff of extruded sealer confirming patency. I do have a couple of little backfill voids. All cases done using gates glidden, .06 ISO sized profiles, .06 tapered gutta percha using a warm vertical condensation technique.

AAE's Updated Antibiotic Prophylaxis Guidelines

As many of you know, on April 19th, 2007, the American Heart Association announced a major change in the guidelines for antibiotic prophylaxis to prevent infective endocarditis in certain dental patients. (Click here to see the official publication)

The AAE has also released it's updated guidelines relating to dental/endodontic procedures. These published guidelines were prepared by the AAE Clinical Practice Committee and are based on the ADA guidelines. (click here to see the ADA's official statement)

The new guidelines note that the practice of premedicating patients before a dental procedure is not longer recommended EXCEPT for patients with the highest risk of adverse outcomes resulting from bacterial endocarditis.

Premedication for patients with mitral valve prolapse, rheumatic heart disease, bicuspid valve disease, calcified aortic stenosis or congenital heart conditions such as ventricular septal defect, atrial septal defect and hypertrophic cardiomyopathy.

The American Academy of Orthopaedic Surgeons have made no changes to their recommendations for patients with joint replacement. This means that those patients should continue to take antibiotics prior to dental procedures. (click here to see the official statement from AAOS)

Idiopathic Osteoslerosis

This patient presents as a 30 year old, white female. Asymptomatic tooth #19 was identified in a routine radiographic exam. Clinical findings: normal to thermal testing, normal to percussion, normal to probing, slight pain to biting on lingual cusps. DX: Normal pulp & periapex

The radiopacent area on the mesial root is noted and diagnosed as an idiopathic osteosclerosis. As a quick review, this is a designation for a uniformly radiopacent lesion that cannot be attributed to any inflammatory, dysplastic or neoplastic source. They may also be found in other locations. Most commonly found in patients between 20 & 40 years old and may have a female predilection. Also appears more commonly in black population. 90% of cases are seen in the mandible, usually in the 2nd premolar/molar area.

No treatment is indicated. Little change is usually seen in these lesions.

Another term that is often used interchangably is condensing osteitis or focal chronic sclerosing osteomyelitis. While looking identical, these lesions are associated with necrotic pulps and are believed to be a result of chronic, low grade inflammation. The interchangable use of these terms can be somewhat confusing. However, accurate pulpal diagnosis will help determine whether the radiolucent lesion is the result of inflammation caused by a necrotic pulp (condensing osteitis) or truly idiopathic (unknown) origin (idiopathic osteosclerosis).

(Source: Neville, Damm, Allen & Bouquot. Oral & Maxillofacial Pathology, 445-446, 1995)

Endodontic Success

This patient presented today with a dull, radiating ache in the lower right quadrant. Clinical examination finds #29 sensitive to percussion, normal probings with prior RCT (30 years). A short obturation is evident. Adjacent teeth #30 & #28 have normal pulps . #29 is diagnosed with Prior RCT & Symptomatic Apical Periodontitis. Retreatment is recommended & completed.


I think that it is great that a root canal, done sometime in the late 70's, can be retreated, using modern techniques and equipment and be functional for another 30-40 years. Unless that root is fractured, there is nothing better than a natural tooth.

Surgical Repair of Post Perforation

This patient presented without pain but presence of draining sinus tract in the buccal attached tissue over #7. The position of the draining sinus tract directly at the level of the post, normal periodontal probings and evaluation of the radiograph made me suspicious of a post perforation. (note the widened ligament to the level of the post, and completely normal appearance at the periapex)
Options discussed included retreatment or apical surgery. Since the crown is all porcelain, we decided to treat surgically.

Ochsenbein-Luebke surgical flap was selected to prevent recession of marginal gingival, and minimal loss of crestal bone. The periodontal attachment was still in tact following flap reflection despite the loss of buccal bone adjacent to the perforation.


Metal tip of the post was visible without any removal of any buccal bone.

The post was counter-sunk using a high speed handpiece.

Preparation of the root. Note that this was not the apex of the root. This repair was being done on the mid-root surface.


Geristore was selected as the restorative material. Since Geristore is a bonded material, moisture control is important. Astringedent was used for hemostasis and the root was acid etched, primed and bonded.

Geristore placed in the preparation and cured.

Geristore was contoured to the root surface.


Final film. This will be an interesting case to follow. Expect a good result and repair of boney defect. We'll continue to monitor this tooth over time. Endodontic surgery has provided a valuable service to this patient prolonging the life of this tooth, the crown and hopefully regenerating the boney defect. Stay tuned for updates!