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Orthodontics/Orthodontic extrusion/forced eruption of maxillary molar?

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Question
Hi, I noticed that you mentioned that you are interested in the intersection of orthodontics with other dental specialties, so I hope you might be able to answer my question about orthodontic extrusion versus crown lengthening.

I have a first maxillary molar with a large filling from 7 years ago when I was in my late 20's, which may (if I'm unlucky) end up needing RCT and a crown (it's been sensitive to percussion lately which they're hoping it's just a sprained ligament due to malocclusion that has now been corrected).  The restoration on the mesial side goes all the way down to the gum, and the gum has in fact receded on that side over the years since the filling was placed (I was told the bone has now readjusted to a healthy position there relative to the restoration margin).  Due to poor oral hygiene when I was younger, my gums have generally receded a lot, although even at the lowest level, the teeth aren't exposed below where enamel ends, and due to good oral care in recent years, except for two spots, I don't have any pockets > 3mm.

I was told that to get a good ferrule on the tooth for a crown, I would need crown lengthening of several mm that would also affect 2-3 nearby teeth.  I was told that this "probably" would not affect the placement of an implant in the future.  I was also told that this would expose cementum below the enamel in my teeth.

The dentists and periodontist I've consulted have brushed off the possibility of doing orthodontic extrusion/forced eruption instead as "unnecessary" and "time-consuming".  I was wondering why that is?  It would seem to me that even if it costs more and takes longer, being able to restore the tooth without the loss of bone to adjacent teeth would be a good thing, versus ending up with multiple teeth with exposed cementum that is more susceptible to decay and has less bone support and a smaller crown-to-root ratio; I also would prefer to reduce the odds of problems down the line if I eventually need implants.  Is there a reason why orthodontic extrusion appears to be so disfavored?  Someone said something about the risk of exposing the root furcation point, but isn't that an equally likely possibility with deep CL?  What are the counterindicators for orthodontic extrusion that might make CL a better option?

Answer
Dear Jonathan,

Thank you for your question. I have been actually consulting with three other dentists on this to get more of a collective opinion for you. I appreciate your inquisitive approach in trying to identify possible other alternatives.  

First let me again state, what I write here are only my opinions based on very limited information. My comments should not be viewed as any form of diagnosis, definitive or otherwise, or any form of treatment recommendation.  Indeed, in the ultimate analysis all final decisions, particularly clinical ones, should only be made by qualified doctors who have had a chance to see you in person and who have had an opportunity to take and analyze proper diagnostic records.

The lack of Xrays, occlusal bite information, crown root ratios, and specific periodontal bone topography information somewhat hinders my ability to respond. It was helpful though that you stated:

1)   You said:

“due to good oral care in recent years, except for two spots, I don't have any pockets > 3mm.”

Of course one can have substantial periodontal bone loss and a very marginal crown root ratio, and still.not have any periodontal pockets.   Anyway, this is a very complex question that you have presented and you bring up many complex points. Let us address these one by one.

2)   You also wrote:

“ I have a first maxillary molar with a large filling from 7 years ago when I was in my late 20's, which may (if I'm unlucky) end up needing RCT and a crown (it's been sensitive to percussion lately which they're hoping it's just a sprained ligament due to malocclusion that has now been corrected).”

I checked with a Board Certified Endodontist and large  “fillings“ can indeed sometimes cause “other” issues to develop. First of all if the restoration is large and made of amalgam (silver filling), this older material has a tendency to experience “amalgam creep” . Amalgam can change shape and in fact sometimes expand somewhat, This can cause the surrounding tooth structure to fracture. Amalgam is held in place by a mechanical locking, unlike many more modern restorative materials which are held in place due to adhesive properties and can in fact strengthen a restored tooth. A fracture from a large amalgam can sometimes extend beyond the enamel of the crown and course down into the root. My Endodontist friend advises me that this can in fact cause endodontic and periodontal bone loss. Periodontal bone surgery and  surgical endodontics in fact can overlap in certain areas.

I hope that the “sensitive to percussion” issue is due to a slight malocclusion. I would have your family dentist carefully evaluate the status of this “filling”. If it is only 7 years old then perhaps the material is not an amalgam.

3) You also wrote:  

“ The restoration on the mesial side goes all the way down to the gum, and the gum has in fact receded on that side over the years since the filling was placed (I was told the bone has now readjusted to a healthy position there relative to the restoration margin). “

Periodontal attachment is generally lost when restorative material such as gold, composite, porcelains, amalgam, or other materials are places where heretofore there had been the natural surface of the tooth. The gum receding is one issue, but equally if not more important is the extent of hard tissue or bone recession. Envision a tooth which vertically from top to bottom consists of a crown (the white enamel) and  a root (embedded in the bone). There is an important Crown/Root ratio which influences the stability of the tooth. A 3 to 1 ratio means that there are three units of root dimension for every one unit of crown length. Teeth sometimes experience changes in the actual root length due to root resorption or blunting of the apex ( end tip) of root.

A tooth’s stability is affected by its crown root ratio, as well as the amount of actual bone encircling the root. Imagine two compromised teeth,  each with a  1 to 1 crown root ratio, namely the length of the root and height of the crown are identical. If one tooth has the entire root length covered with bone, and the second tooth has only half the  length covered, the former is likely to be more stable.

Stability is critical in terms of considering restorative options such as crowns or dental implants. It is also critical in terms of surgical crown extension procedures, or orthodontic procedures to further erupt/intrude  a tooth, change it’s axial inclination, or to bodily move it laterally.

As you can begin to see, assessing you situation without detailed records is difficult.

4)  You also wrote:

“ Due to poor oral hygiene when I was younger, my gums have generally receded a lot, although even at the lowest level, the teeth aren't exposed below where enamel ends. “

This line of demarcation is known as the cemento enamel junction or CEJ. If the bone level has not receded below this, then hopefully there is no profound loss of supportive periodontal bone.  What I hope I am able to succeed in explaining is that there are many factors here dictating the stability of a tooth, and whether orthodontic assisted eruption is viable.

5) You also wrote:

“I was told that to get a good ferrule on the tooth for a crown, I would need crown lengthening of several mm that would also affect 2-3 nearby teeth.  I was told that this "probably" would not affect the placement of an implant in the future.  I was also told that this would expose cementum below the enamel in my teeth. “

I have had many patients who have had crown lengthening procedures, and this is certainly a viable option. I have also undertaken minor orthodontic movements to improve the position of a molar or premolar. I have worked with periodontists and general dentists using both approaches. Exposing the cementum of a root while not optimal is sometimes an acceptable option given the overall risk/benefit of such a procedure. Likewise, orthodontic movement of a tooth sometimes may result in some cementum exposure, but in moderation this is not necessarily unacceptable.

6)  You also wrote:

“The dentists and periodontist I've consulted have brushed off the possibility of doing orthodontic extrusion/forced eruption instead as "unnecessary" and "time-consuming".  I was wondering why that is?  It would seem to me that even if it costs more and takes longer, being able to restore the tooth without the loss of bone to adjacent teeth would be a good thing, versus ending up with multiple teeth with exposed cementum that is more susceptible to decay and has less bone support and a smaller crown-to-root ratio; I also would prefer to reduce the odds of problems down the line if I eventually need implants.   “

Well needless to say I concur completely with your line of reasoning, but don’t take it from me.  I would recommend that you schedule a consultation with a local orthodontist (or two) and afford yourself the opportunity to hear a different perspective. Please note that I am not implying that orthodontics is the only option, nor that it is necessarily the best option. I can not say given no clinical records. If extreme blunting of the root apex is present, or the anatomical crown of tooth is extremely fragile, then an orthodontic approach MAY be contraindicated, but this seems unlikely.

I am quite frankly very favorably impressed by your layperson’s perspective on what are some very subtle  issues. I always advise patients to seek other opinions when they have concerns. I think you can call and schedule a consultation with a local orthodontist. Moreover, although I also treat many patients with clear aligners rather than braces, in this case I would probably recommend traditional braces for added control and precision. Again, check with an Orthodontist, just don’t pick one who claims to use primarily of not exclusively clear aligner therapies.

Also, sometimes orthodontic movement can in fact enhance the bone support of a tooth by improving some of the irregular topographies in the alveolar bone which surrounds the root of a tooth.  Again, without detailed X-rays I can not comment, but your local Orthodontist will be able to provide as assessment.

7)   You also wrote:

“.  Is there a reason why orthodontic extrusion appears to be so disfavored?  Someone said something about the risk of exposing the root furcation point, but isn't that an equally likely possibility with deep CL?    “

Well, I am not sure why orthodontic extrusion (or intrusion) would be disfavored. Although I am a dentist, I am not a Board Certified Periodontist, and therefore can not speak from a Periodontist’s perspective. Likewise, perhaps if a clinician is not an Orthodontist, they may feel uncomfortable providing or recommending certain orthodontic procedures. I have intruded incisal teeth that have over erupted and extruded molars which needed to erupt a little more. Each tooth required a crown for s final restoration. Orthodontic intrusion and extrusion of teeth is a viable option given the right circumstances and health of a tooth.


So, in summary, what is the “Plan” you may ask.

1) Identify two local orthdontists and schedule a consultation  appointment with each.
2) Visit your family dentist, periodontist, etc. to gather copies of your clinical records. Alternatively you can ask them to forward records to the Orthodontist(s) you have selected.
3) Specifically ask each Orthidontist if eruption and any associated axial inclination changes are feasible so as to meet the needs of the general dentist who will be providing the final restoration.
4) Whereas a dental implant does provide a solution, albeit one which is costly, like all dental therapies, they are also known to have failures.  ( A 2010 publication suggests a 7.4 % failure rate in molar implants . Link:

http://www.ncbi.nlm.nih.gov/pubmed/16945030

Here is an additional citation which may be of interest:
http://www.ncbi.nlm.nih.gov/pubmed/20452257

I would very much enjoy hearing back from you, and reviewing any clinical records you may wish to share. Thank you for writing Jonathan, and please stay in touch and let me know how all this works out. Your question was very complex, and I hope I have at least given you a sense of direction of what to do next.

Paul Supan, DDS, MA, MPH
Board Certified Orthodontist

Specialist in Orthodontics
Specialist in Dental Public Health
http://www.braces.com
http://www.leesburgbraces.com

Please allow a week for a reply. I am in full time Private Practice, lecture on occasion, and am involved in many volunteer activities. I am therefore not always able to respond to questions straight away. I also will sometimes consult with other doctors on complex questions. This if course takes time.  Your understanding is appreciated.  

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Paul Supan, DDS, MA, MPH

Expertise

First may I say please set your questions to Public so other readers can benefit from the response. Also, if you look at my comprehensive answers, they are not short 1 or 2 paragraph quickie replies that anyone can type out in < 5 minutes. Instead I often will ask other colleagues in other specialties for their advice in order to provide you the questioner with a more interdisciplinary perspective. This all takes time. I ask for readers to therefore allow 5-7 days. You will be rewarded with a very detailed response.

Because of the nature of Orthodontic questions, any pictures of the teeth and X-ray images would be very helpful. If you write to me and explain that you have crooked overlapping front teeth can be interpreted in many many ways, and my goal is to provide a specific response that meets your needs.

I hold double specialty credentials. I am Board Certified in Orthodontics and Board Eligible in Dental Public Health. I welcome questions regarding Braces, Invisible Braces, & Invisalign, as well as issues involving combination Cosmetic Dentistry and Orthodontic treatment. Orthodontics alone sometimes is not enough to achieve that perfect smile. Gingival (gum) re-contouring, tooth reshaping, bonding and other services are sometimes needed. I also have substantial experience in the areas of Infection Control and Sterilization in the Dental Environment. My personal websites braces.com and Leesburgbraces.com are non-commercial for information purposes only and may provide you with some background to more precisely frame your question for allexperts.com.

Please allow a week for a reply. I am in full time Private Practice, lecture on occasion, and am involved in many volunteer activities. I am therefore not always able to respond to questions straight away. Your understanding is appreciated.

Experience

Board Certified Orthodontist (ABO Diplomate) with over 25 years of Private Practice experience. Second Specialty Certificate in Dental Public Health with research experience at NIH, and Epidemiology Training & Research at Harvard, NIH, and the Centers for Disease Control (CDC) in Atlanta. Postgraduate Masters degree from the Harvard School of Public Health, as well as a Master of Arts Degree in Education.

Organizations
American Dental Association, American Association of Orthodontists, Academy of General Dentistry, College of Diplomates of the ABO, OSAP - Office Sterilization & Asepsis Procedures Organization, Others

Publications
Available upon Request.

Education/Credentials
BS College of William & Mary, DDS Medical College of Virginia, Masters of Public Health (MPH) Degree Harvard School of Public Health. Dental Public Health Specialty Certificate from NIH. Orthodontic Specialty Certificate from University of Rochester Eastman Dental Center. USPHS clinical research experience at NIH, and Epidemiology Training & Research at Harvard, NIH, and the Centers for Disease Control. Fellow of the Academy of General Dentistry (FAGD), and Fully Board Certified Diplomate of the American Board of Orthodontics. Board Eligible in Dental Public Health. Visiting Adjunct Associate Professor at the Meharry Medical College School of Dentistry, Nashville, Tennessee.

Awards and Honors
Available upon Request Please see my personal websites braces.com and Leesburgbraces.com for further personal background.

Past/Present Clients
Available upon Request

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