Teeth & Dental Implants: Not the Same

At the recent AAE Convention, Dr. Hessam Nowzari presented a lecture on implant outcomes.  Dr. Nowzari is a diplomate of the American Board of Periodontology and the former director of advanced periodontics at USC from 1995 to 2012.

Dr. Nowzari discussed the difference between the tooth and an implant from a unique perspective. Often left out of the discussion regarding implants is the importance of the periodontium and how loss of the the periodontium (tooth, periodontal ligament, dental papilla, supracrestal fibers, lamina dura) affects the remaining gingival esthetics, including the esthetics around the dental implant.

It is well known that anterior gingival esthetics around an implant are one of the most challenging parts of implant dentistry.  The reason this is so challenging, is that the natural periodontal tissues (see image) that give the gingiva it's phenotype (appearance) are gone.  An implant's best chance at "natural-looking" gingiva/papilla is a natural tooth next door!  Dental papilla belong to teeth. 

While implants have an important part in dentistry, an implant can never effectively reform the periodontium.  The bundle bone and the family of fibers (dentogingival, dentoperiosteal, alveologingival, periosteogingival, interpapillary, intergingival, circular, semicircular, transgingival, intercircular, transeptal fibers) that create the architecture of the dental papilla all belong to the tooth.

This debate between implants and endodontics should not exist.  Implants and root canals are not alternative treatments.  If a tooth and its surrounding periodontium is in tact, we should make every effort to preserve them, because an implant cannot restore these periodontal tissues and loss of these tissues leads to a host of other challenges.

 Dr. Nowzari hosts a periodontal & implant symposium that may be one of the few (if only) implant CE events that is not sponsored or underwritten with any commercial interest (also available for download).  It may also be the only of its type where endodontists and implant surgeons are participate together.  We would highly recommend you check it out.

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.

Missed Canals Cause Root Canal Failure

Endodontic therapy has a well documented rate of success.  There are situations where initial endodontic therapy fails.  In a previous post, we discussed the role of bacteria in root canal failure despite the separation of a rotary instrument.

Root canal failure, as well as failure of any dental treatment, is often associated with bacteria. Bacteria that is incompletely removed from the canal system during endodontic treatment will cause root canal failure. Unfortunately, sometimes that failure is not identified until months or years later and then some people condemn root canal therapy as unsuccessful, when the cause may be incomplete root canal therapy leaving bacteria behind in the canals.

The following example is a root canal that was done 13 months ago by an associate dentist in a general dental practice.  This can sometimes create a difficult situation for the owner dentist, when the patient returns with an abscess a year later.

Root canal done 13 months earlier.  Large periapical lesion on mesial root.  Short root canal filling on mesial canals.  The prognosis for this tooth was poor at the time of completion because the MB canal was not cleaned and obturated. Bacterial left behind will continue to cause periapical disease.

CBCT shows missed MB canal and short ML canal filling.

Missed MB canal located immediately with microscope.

All canals cleaned and shaped.  This tooth now has good prognosis for success.

As mentioned, bacteria left behind will cause failure of root canal treatment.  Root canal failure is most often caused by failure to completely remove bacteria from the canal system or failure to seal out bacteria from re-entering the canal system.

CBCT as Aid In Removal of Separated File

Removal of a separated instrument is rarely a simple task.  The closer to the apex, the more difficult the removal.  In this case, tooth #19 had a separated instrument 6 yrs earlier. The tooth had become symptomatic and the patient was having extensive crown and bridge work done.

A CBCT was taken to evaluate the separation in 3D.  This image was very helpful because it told us the anatomy of the mesial root. It shows clearly that the mesial root is a single root, rather than two separate roots.  With this information, we can plan to remove some tooth structure between the MB and ML canals in our attempt to access and remove the separated instrument.  It also showed us that there were 2 separated instruments in the MB canal.  This information is crucial in our ability to remove the spearated instrument. (The radiographic imaging also warned us not to remove any dentin mesial to the prepared space to prevent root perforation)

This treatment can only be accomplished with the use of the dental operating microscope and use the of ultrasonic instrumentation.  Approximately 1 hour of treatment time was used in removing the separated instruments.

2 separated instruments

Final obturation.

Take home message from this case...

Always easier to prevent a separation than remove a separation.

Patients should be informed if an instrument separation occurs.

Advanced imaging (CBCT) provides valuable information that affects the course of treatment.

Microscopes are an indispensable tool in modern endodontic therapy.

Remembering James H.S. Simon DDS (1934-2013)

On Sunday, Feb 3, 2013, Dr. James H.S. Simon passed away. Dr. Simon was one of the pioneers of modern endodontics.  He dedicated his career to education and was truly an amazing teacher, mentor and friend.  I'm grateful for my association with Jim and the things he taught me about endodontics.

Dr. Simon (Chief) and his posse at Jackson Hole, WY - Oct 2012 meeting of American College of Endodontists.

The following bio was provided by Dr. Ilan Rotstein of USC.

 

Dr. Simon was born in 1934 in Boston. Between the ages of 14-18 he attended the Phillips Exeter Academy in New Hampshire, known for its excellence in education, and graduated from the Academy in 1953. Between the ages of 18-22 Dr. Simon attended Bowdoin College in Brunswick, Maine, where he majored in biology. He spent the next 4 years in Temple University School of Dentistry in Philadelphia obtaining his D.D.S degree. Following dental school Dr. Simon spent 2 years at Boston University School of Medicine where he studied oral pathology and endodontics with Henry Goldman, Kurt Thoma and Herb Schilder and received his certificate in endodontics. For the next 3 years he was engaged in a private practice in Quincy, Massachucetts, where he limited his practice to endodontics. After 3 years of private practice, Dr. Simon joined the Veteran’s Administration in White River, Vermont, treating endodontic cases and in addition serving as a research associate at Dartmouth Medical School in Hanover, New Hampshire.

In 1968 Dr. Simon joined the VA Medical Center in Long Beach, California, in order to start the first endodontic residency program there. For the next 32 years, Dr. Simon was the Director of the Endodontic Residency Program at the VA Long Beach where he mentored and trained more than 60 residents. This period of 32 years was the longest full-time teaching program under one director in the nation. During that period, Dr. Simon also held a part-time teaching position at USC School of Dentistry where he taught together with Al Frank, Dudley Glick, John Ingle and others. In 1974, he joined the faculty at Loma Linda School of Dentistry as part-time faculty. In July 2001, Dr. Simon was recruited to USC where he served as Professor of Clinical Dentistry and Director of the Advance Endodontics program. During that time he mentored and trained more than 110 advance endodontic students.

Dr. Simon was a Diplomate of the American Board of Endodontics, President of the College of Diplomates of the American Board of Endodontics, Director and President of the American Board of Endodontics, Fellow of the American College of Dentists and

Fellow of the International College of Dentists. He was member of many prestigious dental organizations and held leadership positions in the American Association of Endodontists. Dr. Simon published extensively in the dental and endodontic literature and in 2005 he received the Louis I. Grossman Award by the American Association of Endodontists. This most prestigious award is given to an author for cumulative publication of significant research studies that have made an extraordinary contribution to endodontics. Dr. Simon was an international authority in the field of endodontics and used to lecture extensively at universities and professional meetings in the United States and throughout the world.

Jim is survived by Helen, his wife of 53 years, his children Jeffrey, Linda and David, and his grandchildren Alexis, Morgan, Jake, Jordan and Jason.

Bacteria Cause Root Canal Failure - Not Separated Instruments

Bacteria are the main cause of endodontic infection and endodontic failure.  If we can remove the bacteria and prevent its re-entry into the canal space, then we can expect success.  Separation of an endodontic instrument does not cause root canal failure, rather the incomplete removal of bacterial causes endodontic failure.  The follow case demonstrates this very clearly. File separation occurred with initial endodontic treatment. The separated file prevented complete cleaning and shaping of the canal.  Upon retreatment, the separated file was not removed, but rather pushed apically. However, the canal was cleaned, shaped and filled to the apex with the separated instrument left in the tooth.  The periapical lesion healed and the tooth is asymptomatic and functional.  I often explain to patients that a separated instrument is not a big problem, unless it prevents us from completely cleaning and shaping the canal.

Prior RCT w/ apical lesion. Small file separation preventing complete shaping and cleaning.

Separated file pushed apically and not retrievable.

Complete cleaning and obturation to the apex. Separated file at the apex.

Removal of bacteria has led to complete healing despite the presence of the separated instrument.

Lateral Portals of Exit

As clinician readers know, the canal anatomy of teeth is rarely simple. Lateral portal of exits (lateral canals) are a significant challenge to clean and are present in many of the teeth we see for root canal therapy. In a previous post, I discussed the use supplemental irrigation and ultrasonic instrumentation to clean isthmus tissue. That post can be found here: http://www.theendoblog.com/2012/07/the-isthmus.html I use these same techniques to address lateral portal of exits. These lateral exits are very common, but with proper irrigation, they can be predictably addressed.

Sometimes, as in this #19 below, the exit can be found at the apex in the form of a sharp distal turn or delta. Direct instrumentation may or may not be possible with small, pre-bent files (6 or 8).

These exits can also be found in the furcation region. If untreated and contaminated with bacteria, they can feed furcation radiolucencies and cause attachment loss (probing). Here is a straightforward #30.

 

 

Untreated, you will see radiolucencies centered on the exit as in this #9 retreated below. I measured to the depth of the lateral canal and focused my irrigation and irrigant activation at that level.

 

 

 

 

Always be aware that the potential for more anatomy exits. With this #28, I found 3 canals splitting at midroot and thought I had found all the anatomy. Fortunately, extensive irrigant activation picked up a lateral exit off the mesial buccal canal in the apical third. Tooth #29 is scheduled for retreatment.

 

In summary, do not believe for a second that sticking a file in a canal completely cleans a canal system.

 

Merry Christmas!

 

Justin Parente

Alpharetta Endodontics

www.Alpharettaendo.com

www.facebook.com/alpharettaendo

 





Why Is It Better to Save a Natural Tooth?

A patient recently asked...

 I'm a healthy 47 year old male. My upper central incisor (#9) was struck (trauma). It cracked vertically to the gum line, and then cracked horizontally to the lateral edge (resulting in an inverted "L" shaped fracture).

My general dentist first tried applying a layer of bonding, which appeared to be acceptable both aestetically and structurally.

6 weeks later, severe pain started to develop. I went back to my dentists and he said that there is no sign of infection, but that the pain is likely from the nerve dying. We agreed that we should go with either a root canal + crown, or implant + crown.

As a mechanical engineer, I'm leaning towards the implant, because it seems more "fool proof", especially considering that the existing tooth has been structurally compromised down to the gumline.

But the one thing that still has me second-guessing the implant option is that endodontists and periodontists both seem to universally agree that "It's better to save the tooth whenever possible."

So I have to ask: WHY???

Why is it "better to save the natural tooth" if it is subject to future decay (in particular at the base of the crown) and is also subject to brittleness following the root canal?

As a mechanical engineer, I like the prospect of an inert metal or zirconium implant that is not subject to these potential future modes of failure.

Please share your insights in the context specific to my situation described above. Much appreciated. Thank you. 

While it may seem a simple solution to replace a tooth with an implant and then avoid future issues like decay or root fracture, there are some important reasons why the specialists are recommending preserving the natural tooth if possible.

Periodontal Ligament attaches the root to the bone

Teeth and implants are not the same. The main difference between a tooth and an implant is that a tooth has a periodontal ligament. This ligament attaches the root to the bone and acts as a shock absorber for the tooth.  Without a periodontal ligament, when you touch, tap or chew on the tooth, you cannot feel the tooth or how hard you are biting.

The sensory function of the periodontal ligament helps you know when something is wrong with your tooth. If the tooth is hitting too hard, the ligament senses it. If there is infection around the tooth, the ligament senses it. The sensory function of the periodontal ligament is very important to dental health.

The periodontal ligament also supports the surrounding bone. When the ligament (tooth) is removed, bone loss naturally follows. The periodontal ligament also is a home to multiple cell lines which support the bone such as: osteoclasts, osteoblasts, fibroblasts, cementoblasts, cementoclasts, and stem cells. The periodontal ligament allows the tooth to be moved through the bone (orthodontics).

The periodontal ligament has an important role with esthetics.  When the ligament is removed, and bone loss naturally occurs, gingival recession follows. This can change the esthetics of the tooth, especially in the anterior esthetic area.

The periodontal ligament also has an immunological purpose. The ligament and the gingival connective tissue fibers form a barrier to protect the bone from bacterial invasion.

There are times when the natural tooth cannot be saved.  If the root is fractured, then the tooth is not savable.  The endodontist is the most qualified specialist to determine if a root is fractured.  At Superstition Spring Endodontics, we use microscopes and focused field, high resolution CT scans to aid in the diagnosis of root fracture.

The periodontal ligament is the difference!

In these particular cases, a dental implant may be the ideal way to replace a missing tooth.  Marketing of dental implants by manufacturers has made this treatment options well known to the public, however, dental implants are not free of complications or need for revision (additional) treatment over time. By understanding the complications that can occur with implants, it will help to understand why specialists recommend, "saving the tooth if possible".

The ligament is a shock absorber

Many of the complications with dental implants can be associated with the lack of a periodontal ligament. Here are a few of the ways the lack of periodontal ligament can cause complications with dental implants.

The periodontal ligament is the shock absorber for your tooth.  Can you imagine driving a car without shocks? An implant, without a ligament, has no proprioception (sense of feeling). This means it is difficult for you to "feel" how hard the teeth are hitting together. Porcelain chipping, cracking and loosening of implant screws are all common complications with implants, mostly due to the lack of a periodontal ligament and the proprioception it provides.



Fortunately, with implants adjacent to natural teeth, you maintain proprioception from the adjacent natural teeth so your chewing can still feel the same. However, it is difficult to feel if the implant crown is hitting too hard, like you would with a natural tooth. Your dentist must be careful to get the implant crown adjusted just right, and will often times flatten the crown to prevent excessive force on the implant or make the biting contact light.

Bone loss over time is expected

The periodontal ligament transfers the force from the tooth to the bone. That constant transfer of force to the bone, keeps the bone functioning around the root.  When the periodontal ligament is gone, bone loss naturally follows. Some studies say that up to 0.2mm/yr of bone loss can be expected. There are theories as to why this occurs. Some think its simply the mechanical forces on the implant transferred to the bone that causes the recession.

Bone loss in anterior can cause esthetic defects

Loss of bone around an implant can cause unsightly changes in the anterior esthetic zone. While the implant may be functioning, esthetic failure is a well known complication with anterior implants.

Peri-implantitis is the growth of bacterial biofilms on the implant surface, causing chronic inflammation leading to bone loss.  Many people are not aware that an implant can get peri-implantitis, just like a tooth can get periodontitis, both of which can eventually lead to the loss of the implant/tooth.   The periodontal ligament plays an important role in the preservation of the bone around a tooth.

Historically, implants have been classified as "surviving" or "failed" based upon mobility of the implant. New implant studies have suggested that implant intervention may need to be done at earlier stages before too much bone loss has occurred.  It was proposed that surgical intervention may need to be done when an implant is considered "ailing" or "failing" rather than waiting until enough bone loss has occurred to consider it "failed".

In a recent study published in the Journal of Oral and Maxillofacial Implants, a comparative study between the success rates of implants and root canals revealed no significant difference in the two options and emphasized that treatment decisions should be made on factors other than outcomes.  In other words, neither of these treatment options can claim to be more successful than the other.  These treatments are different, and each has its own pro's and con's.

Implants have an important role in dentistry.  I routinely recommend implant placement for missing teeth or teeth that are too damaged to save. However, implants are not teeth and we should try to preserve our natural teeth if possible.

For more information on the longevity of implants vs. natural teeth, click here or here.

Root Canal Surgery to Repair Post Perforation

#6 Post perforation on a long span (7 unit) bridge. Pt is insistant that she does not want to lose this tooth or bridge at this time.  Lateral radiolucent lesion is present adjacent to the perforation.

CBCT taken to evaluate the position and extent of perforation, bone loss and possible surgical intervention. Given the treatment options, the patient wishes to try and maintain the tooth with surgical repair of post perforation. Pt understands that post repair will not improve coronal margins, but does not wish to replace bridge at this time.

Surgical flap reflected, post perforation located, 2-3mm post resected, lateral root preparation created.

Geristore used to repair root.

Lateral root restoration contoured to adjacent root.

Post Op radiograph showing perforation repair.

6 month recall showing initial healing. Pt is asymptomatic and fully functional.

At 18 month recall, bone has healed completely, tooth #6 is asymptomatic and fully functional.  Tooth #4 is now testing necrotic w/ asymptomatic apical periodontitis. RCT has been recommended.

 This case demonstrates how a skilled endodontist's surgical abilities can save what would seem like non-restorable, iatrogenic damage.

Apical Surgery for Complete Endodontic Healing

Sometimes endodontic surgery (apicoectomy) is required for complete periapical healing - even on teeth with ideal (or close to ideal) non-surgical treatment.  We are not always able to identify the reason that apical surgery is required. Perhaps it is complex apical anatomy and the inability to completely clean, shape & fill it.

The apical third of the root tends to have the most anatomical variation.  For a greater appreciation of the complex anatomy of the apical canal, check out the anatomy shown by Dr. Ronald Ordinola Zapata and others published at the cleared teeth blog.

 The following case demonstrates the occasional need for endodontic surgery, despite adequate non-surgical treatment and retreatment.

Tooth #14 was asymptomatic, but a large pa lesion was noted. Tooth was diagnosed as necrotic pulp with chronic apical abscess (sinus tract present). Note the size of the lesion and its elevation of the floor of the Mx sinus. RCT was recommended.

RCT was completed.

 At 1 yr recall the tooth was still asymptomatic and functional, but the lesion does not appear to be improving as expected and a sinus tract has again appeared.

ReTx completed. No cracks or fractured seen. No additional canals located. No sign of the cause of initial failure.

7 month recall after Retx. Tooth still asymptomatic and fully functional, but sinus tract returned.  Apicoectomy recommended.

 

 

 

 

Apicoectomy completed under microscope with MTA retrofill

6 month recall following apico finds the tooth asymptomatic, fully functional, periapical bone healing.

 The patient was pleased to be able to save the tooth. The periapical bone has healed nicely and the anatomy of the sinus floor once again looks normal.

In this particular case, non-surgical RCT and retreatment - both done with use of operating microscope, failed to resolve the infection.  Apical surgery was required. At Superstition Springs Endodontics, we are committed to saving teeth and have all treatment options available to help people save their natural teeth.