Resorption of Calcium Hydroxide Paste

Calcium Hydroxide is widely used in endodontics for a number of purposes. Its antimicrobial properties are attributed to its high pH (basic), destructive effects on bacterial cell walls and ability to dissolve organic tissue. It is used routinely as an intracanal medicament. It is also used for apexification, apexigenesis, treatment of root resorption.

Ca(OH)2 used in endodontics is made with Ca(OH)2 powder, a vehicle and a radiopacifier. Most common radiopacifiers are barium sulfate, bismuth or compounds containing iodine or bromine. While radiopacifiers make the calcium hydroxide more visible radiographically, some radiopacifiers are known to resorb at a slower pace, sometimes making it difficult to see the subtle changes.

While the control of a paste material at the apex of a canal can be very difficult, the resorptive properties of calcium hydroxide make it a very forgiving material. Extrusion of calcium hydroxide past the apex of a tooth is not uncommon. In fact, there are some who would recommend deliberate extrusion in the case of a large, chronic periapical lesion to help in the healing of such a lesion.



Calcium hydroxide (Ultracal - Ultradent - 35% Ca(OH)2 with barium sulfate) was used during treatment of this tooth to control exudate prior to obturation. A significant amount was extruded past the apex in close approximation to the maxillary sinuses during the endodontic treatment.




14 months later, the patient returned for treatment of #14. Our recall radiograph of #15 shows complete resorption of Ca(OH)2. The patient had no complaints and is in full function.



Sources:

Hasan Orucoglu, Funda Kont Cobankara, "Effect of Unintentionally Extruded Calcium Hydroxide Paste Including Barium Sulfate as a Radiopaquing Agent in Treatment of Teeth with Periapical Lesions: Report of a Case", Journal of Endodontics, July 2008 (Vol. 34, Issue 7, Pages 888-891)

The Evolution of Implant Success

The 7th Annual Spring into Dentistry seminar was held on March 6th, 2009 in Mesa, AZ. The guest lecturer was Dr. Robert London of Seattle, Washington. Dr. London is currently a clinical professor and director of graduate periodontics at the University of Washington. Prior to his work at UW, Dr. London was director of graduate periodontics at NOVA Southeastern and at University of Southern California.
Dr. London's presentation was entitled, "Enhancing Dental Outcomes".

While a good portion of his presentation had to do with implant treatment planning and preparation of implant sites, he made some comments that I found fascinating.

He used an analogy of a pendulum to describe the acceptance of dental implants into mainstream dentistry. Early on, there was some resistance to accepting them into everyday practice. Like the swinging of a pendulum, treatment with dental implants then became the solution to every situation. Now that the pendulum has swung to both extremes, we are now hopefully settling somewhere in the middle.

He also discussed the changing definition of success with implants. Early on, successful implant therapy meant osseointegration. If the implant was not loose, it was considered a success. In endodontics, success has always been defined very strictly as the complete resolution of signs and symptoms and complete healing of bone. With two such different definitions of success, it is no wonder that there has been misinterpretation regarding the treatment outcomes of the two different treatments.

Dr. London pointed out that what was once considered a successful implant (osseointegration alone) may no longer be an acceptable treatment outcome. Successful implant therapy now requires getting the implant to integrate in the right position, where it can support a prosthesis and look like a natural tooth. This is a major difference from simple osseointegration.

Dr. London stressed how important it was to have an interdisciplinary approach to dental treatment so all specialties are included in the best treatment approach for each patient.

We were pleased to have Dr. London come and share some of his expertise regarding periodontal bone grafting and implant treatment. We hope that the balanced approach to endodontics and implants which he described continues to gain momentum.

Longevity of dental implants vs. natural teeth

Longevity of natural teeth surpass the dental implants.
February 16, 2009

A lot of marketing has been done in the past few years to present dental implants as a better choice than a tooth that can be retained with endodontic therapy.

This has resulted in many un-necessary extractions, increase in implant failures, associated lawsuits and complaints to the states board.

Recently the academic community in the fields of periodontics and prosthodontics have come out with some evidence-based recommendations regarding natural teeth vs. dental implants.
For those of you who may be interested, here are some quotes from these articles:


Periodontology 2000
Lundgren D, Rylander H, Laurell L
Vol 47, 2008: 27-50
“It is well documented that properly treated natural teeth with healthy but markedly reduced periodontal support, are capable of carrying extensive fixed prosthesis for a very long time, with survival rates of about 90%,provided the periodontal disease is eradicated and prevented from re-occuring.”
“Based on assumptions that implants perform better than periodontally compromised teeth, teeth that could be saved and used as support, are extracted and replaced with implants, sometimes on doubtful indications.”
Peri-impantitis (loss of at least 2 mm of marginal bone) at one or more implants have been found to occur in 16-28% of implant patients after 5-10 years and with higher prevalence among patients with multiple implants.
“The natural tooth should not be considered an obstacle but a possibility, whether or not the treatment is to include implant placement.”
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Journal of Clinical Oral Implant Research
Holm-Pedersen P, Lang N, Muller F
University of Copenhagen
2007, 18(suppl) 15-19
“Oral Implants when evaluated after 10 years of service do not surpass the longevity of natural teeth even of those that are compromised, for either periodontal or endodontic reason. “
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Journal of Oral Rehabilitation;
2008,35 (suppl.1) 2-8
Consensus statements and recommendations of the European Conference on Evidence-based Reconstructive Dentistry: Implants and/or teeth

(Gathering of major European researchers and clinicians who were periodontists and prosthodntists )

Some of the recommendations were:
Implants do not have a better prognosis than teeth with reduced marginal bone support.
Dentist should not recommend extraction of these teeth.
There is no evidence available to support an aggressive approach in early extraction of teeth, to preserve bone for later implant placement.
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Journal of Prosthodontics ; 2008, Volume 17: 345-347
Editorial : Inconvenient truths by George Zarb,DDS ( Dr Zarb is one of the pioneers of the field of implantology)

“The integrity of purpose and scientific rigor that characterized the original osseo-integration clinical research has been largely discarded as passe’.”

“Partnership with commercial enterprise now dominate continuing education.”

“New lecture circuit celebrities keep being recruited to promote osseo-integration's newer and expanded promises, albeit it falls significantly outside the technique’s initial oral ecological context.”

“We risk overlooking safety, simplicity and prudence in our clinical judgment.”

“The risk of yet another anarchic phase in treatment decision making has resurfaced."
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I think these statements speak for themselves.
I welcome your comments.
Robert Salehrabi,DDS

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.

The Endo Blog Welcomes a New Contributing Author - Dr. Robert Salehrabi

I would like introduce and welcome a new contributing author to The Endo Blog, Dr. Robert Salehrabi of Advanced Microscopic Endodontics (Aurora, CO). For quite some time I have considered the idea of adding additional authors to help provide more frequent postings, give additional clinical expertise and perspective and share the workload associated with the blog.

Dr. Salehrabi started his education at University of Massachusetts. He earned his DDS with a minor in Oral Medicine from State University of New York (Buffalo). His endodontic specialty training was completed at University of Southern California.

While a full time member of the USC endodontic faculty, Dr. Salehrabi became well known for his research. His work entitled "Endodontic Treatment Outcomes in a Large Patient Population in the USA: an epidemiological study." (JOE 2004 Dec:30(12):846-50) has been recognized as one of the most important endodontic research articles published in 2004. In a groundbreaking study to evaluate the long term treatment outcomes of non-surgical endodontic treatment, over 1.4 million root canal treatments done by specialists and generalists alike were evaluated. This study provides the clinician with useful tools for clinical decision making and assessment of tooth prognosis.

Dr. Salehrabi has presented endodontic lectures internationally as well as seminars throughout the United States.

While currently in private practice in Aurora, Colorado, Dr. Salehrabi maintains his teaching position as an associate clinical professor in the Department of Advanced Endodontics at USC.

Welcome Dr. Salehrabi!

Root Canals Save Your Natural Teeth

Occasionally I will use the images posted on the endo blog to aid in communication with patients. Whether trying to explain the healing of an abscess or show the patient how their tooth is cracked or fractured, a picture is worth a thousand words. Access to the internet in the operatory allows the endo blog to serve as a useful educational tool with patients. These images designed for patient education are written in lay terms will be labeled "patient education". Feel free to use them in your discussions with your patients. (click on the image for a larger, high resolution image)

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.