Bite Point

Dental Pulp Calcification And Changes With Age

The dental pulp, or root canal system of a tooth, is living tissue with a blood suppy and nerves and untold millions of cells.  This tissue is involved in the formation of teeth, and cells in there are responsible for laying down the dentin, the main body of your teeth that lies under the almost diamond-hard enamel:

 
Primary dentin is the main body of dentin that forms when a tooth develops, up to the point where it erupts into the mouth and becomes fully functional, chomping away at things like cashews and crunchy granola with reckless abandon.  The process of forming more hard tooth slows down at this point, and yet the cells continue to produce, very much more slowly, secondary dentin.  This is simply dentin that forms after root growth is complete.  Of course, it's not as if your pulps switch over at an exact time- like, your lower first molar transitioned from primary to secondary dentin on Tuesday, August 1, 1989 at 2:10 in the afternoon.  Still, cross sections of teeth viewed under a microscope do show the transition from primary to secondary dentin, much like the rings of a tree can be seen in its trunk.

Over the course of our lives, secondary dentin makes the pulp smaller, and this can easily be observed on X-rays.  Here is an X-ray from a 9-year-old; we can see teeth at various stages of development.  In all of her teeth, the pulps are very large and account for much of the inner volume of the tooth:

 

Our next X-ray shows the teeth of a 28-year-old.  Even at this young age we can see that the pulps are smaller due to the deposition of secondary dentin; they occupy less of the internal volume of the teeth:

 

 

There is another kind of dentin called tertiary dentin or reparative dentin.  This is dentin that is formed a bit faster again, in response to external stimulation like cavities or fractures.  Even injuries that do not crack teeth cause damage, as they push teeth around in their sockets and injure the supporting bone and ligament.  All of these processes stimulate the formation of tertiary dentin.

The idea behind tertiary dentin from the body's point of view is that it walls off the dental pulp from the source of the injury.  Pulps have a delicate blood supply and are very prone to getting infected if overly traumatized by cavities, injury or severe gum disease.  This circle-the-wagons strategy is a dual edged sword, if I may be allowed to stew such a gumbo of metaphors.  Because you see, as the pulp gets smaller it does recede farther from the cavity, which is laden with harmful bacteria, but the pulp also gets weaker, in part because its blood supply becomes ever more delicate.

It's like running away from a dangerous animal, but running into a canyon with no exit.  Sooner or later, we'd have to face that animal- precisely at the point where we're most tired out.

The more fillings, injuries, or gum disease that a tooth faces, the more tertiary dentin gets deposited.  Couple that with the secondary dentin from normal aging, like in this 84-year-old, and we see pulps- or, to toss up a non-sequitur, we don't see pulps- that look like this:

 
That one lower tooth with the white lines in it has had a root canal treatment long ago.  I do certainly hope that my patient doesn't come to need root canal therapy on those upper teeth where the arrows "point to the pulps that we can't see", though, because the canals will be awfully hard to find and clean and fill.  And the irony remains that these dental pulps are more delicate than ever, as far as they may be from injurious cavities and the fillings that we do to treat them.  So there is a risk...

For more on dental pulp calcification, see:

http://rickwilsondmd.typepad.com/rick_wilson_dmds_blog/2010/09/dental-pulp-calcification-spelunking-in-the-dentin.html

And consider allowing the magnificent Katherine Clark Gray and our clever Caries Clock teach you how to avoid cavities in the first place:

 http://www.smilephiladelphian.com/clock/Caries.php

http://www.katharineclarkgray.com/blog/

Loyalty

What does loyalty really mean?

At its core, I think it essentially involves kindness.  Kindness and a willingness to be giving to the ones we care about.

Loyalty means that we don't walk away.

Loyalty cannot abide indifference.

The other kinds of "loyalty", like the illusion that a professional sports team actually cares about its fans, are fake.  They depend on a monetary relationship.

With loyalty, there can be a monetary relationship- but it can't be the only thing.  True loyalty requires kindness and giving.

 

Dentitions of Senior Citizens

We ran our year-end reports and one statistic in particular set me to thinking.  Woolgathering and mulling, actually.  Taking a snapshot at 2010's twilight we see that 8% of our patients are age 80 and over.

And nearly all of these excellent folks have most or all of their teeth.

Oh, sure, they may have crowns to restore teeth that must have got hit with decay when they were younger.  (That's the thing about teeth- being hard, mostly mineral objects that don't have the healing capacity of tissues made up of living cells, they really show the wear and tear that we subject them to, whether from decay or excessive grinding.  They don't "heal" in the traditional sense of the word.)  Our older patients may also have bridges or implants to replace a number of missing teeth.  Some even have partial dentures because they find it economically challenging to replace a number of missing teeth with "fixed" restorations, bridges or implants that stay in place.  Still, modern partials can be made very stable and esthetic.

Few of our patients, however, have full dentures, especially without implant support.  A denture with implant support is an oral Rock of Gibraltar, an immovable object that is locked and loaded and ready to face that irresistable force of "Lobster Thermidor a Crevette with a mornay sauce served in a Provencale manner with..."  Oh, you know the rest...

When I first started in practice here, though, in (gasp!) 1988, the vast majority of our patients who were 80 and older had removable dental prostheses- full or partial dentures.  They also tended to have breakdown of their bites, crowding, high decay rates, uncontrolled plaque and gum disease... Their dental health was much poorer than the population group who is 20 years younger and is now "coming up" into the eldest age range that human beings commonly attain.  80 to 100!  How fortunate we are that so many of us can live that long these days.

In any event, I remarked on this to Dr. Sukoneck last night and he replied that, although we now make only a few dentures each year, mostly replacements, not new ones- years ago, he made a dozen or more dentures a month!  I cannot even conceive of such a thing happening now.

The reasons for these incredible positive changes in the dental health of American seniors are complex.  One major factor is that in the early part of the 20th century dentistry was often painful and the technology was primitive, even by the overall medical standards of the day.  Sugar was also readily available and awareness of its role in causing cavities was minimal.  Fluoridation of water was still decades away, and in many communities it never happened.  Thus it is documented that from the 1910's to the 1940's, 95% plus of Americans' back teeth had decay or fillings.

Thus the oldest patients that we saw 20 years ago did not, generally speaking, benefit as much from preventive dental care nor from the improved treatments that became available later.  Much progress has been made, and this progress has benefitted the oldest patients that we see now.

In looking for a picture for this post, this one came to mind- my Dad (quite natural-toothed himself) on the wing of a P-47 Thunderbolt.  Just two weeks after his 90th birthday...

 
Casual Insouciance at 90!