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Periodontics/Orthodontic extrusion v. Crown lengthening


Dr. Kong,

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 next 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?

Dear Jonathan,

Crown Lengthening and Ortho extrusions are both adjunct procedures to augment the predictability of another definitive procedure in dentistry.  Ortho extrusion is never better than Crown Lengthening and vice versa.  However, Ortho extrusion is more conservative in treatment than Crown Lx. in general.
The reason why your dentist may have 'brushed off' orthodontic extrusion as 'unnecessary' and 'time consuming' is because it may not be very practical in your situation.  The decision to use Ortho Extrusion vs. Crown Lx should be situation based. Is it practical for the patient? And is the procedure predictable for the patient? How much do you have to extrude? Orthodontic movement (extrusion or intrusion) especially on a molar tooth (in your case maxillary molar with 3 roots) is one of the most challenging tooth to manipulate orthodontically; Unless TAD's (Temporary Anchorage Device) are used, they often can lead to significant unwanted movement of the adjacent teeth.

That said, this is something you may need to consult an Orthodontist.  If you have time and money (both of which will be more), Ortho extrusion is an option you might want to look into, but make sure it's fits your needs for your own dental situation. In dentistry, one way is never always better than another.  You have to take into account, predictability, practicality and surgical/non-surgical preference.

Hope that helps.



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John Kong, DDS,


I am a board-certified periodontist and an expert on dental implants. I am currently in private practice at Better Living through Dentistry. I can answer questions related to the treatment of periodontitis (gum disease), dental implants, sinus lifts, bone grafts, gum grafts, surgical exposure of teeth, and minor orthodontics.


I have been practicing periodontics and placing dental implants since 2006 on the Upper West Side, Manhattan, NY and in Forest Hills, Queens, NY at Better Living through Dentistry. I am currently an attending and Chief of Implantology at Flushing Hospital Medical Center.

American Board of Periodontology, American Academy of Periodontics, American Dental Association, New York State Dental Association

Wesleyan University / Amherst College, BA; SUNY Stony Brook Dental School, DDS; University of Medicine and Dentistry of New Jersey, Certificate in Periodontics; New York University, 1-year program in Full-Mouth Reconstruction; Certified in Invisalign

Awards and Honors
Northeast Society of Periodontists Achievement Award

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