Bite Point

Frisbees

I would like to talk about a teacher. There are many I could riff on. I will choose Dr. Byron Kern because I just saw in the Pennsylvania Dental Journal that he passed away recently. He was 94.

Dr. Kern was one of those many practicing dentists who (as I have done) gave of his time to teach part-time in a dental school or residency, for little or no compensation. He had the knowledge and patience to teach full dentures exclusively. This is a very subjective and demanding art; it was expecially so in the days before implant support made firm anchorage possible.Dr. Kern taught me that humor was an excellent addition to all the science, art, and human relations we must know so much about in order to treat our patients successfully.

When I was delivering my very first completed full denture to a patient, it fit ideally. This had a lot more to do with Dr. Kern's guidance than with my skills at that point. He had taken me to the end result with all the thrashing at the beginning, which as many of you know is the best way to go on any project. My patient was pleased, I was pleased, and Dr. Kern said, "It's a Frisbee!" This, from a man who was hitting seventy! I was tickled denture-base pink with the idea of calling dental restorations that fit ideally with no adjustment "Frisbees."

To this day, in our office, Frisbee is the word we use for things that fit without adjustment.

After that time, a new patient was scheduled with me who had an unusual request. She was an Eastern European woman who wanted a gold-based denture. This is a denture with a cast gold alloy internal portion that fits against the gum tissues. Up from that comes the pink acrylic and then the artificial teeth. They are very accurate, these gold-based dentures, just rare to make because of the added expense. Mind you, the gold is to be very thin, and it's an alloy, but still: expensive.

So we got the base back from the lab as a first step and someone there had lost their mind. The gold base we recieved was massive. It must have contained an entire one of those ingots that you always saw referred to in 60's sitcoms and Bugs Bunny cartoons along with a reference to Fort Knox, an entity that many young people today are probably completely unaware of. In any event, this denture base could have been a buttressing member for the Market Street El, it was so big and heavy.

I showed it to Dr. Kern with marked trepidation. He took one look at it and then uttered those immortal words: "Rick, if we made her a denture with this base and she went swimming, she'd sink and drown."

And with that hilarious comment we sent it back and had it remade- too small the second time. Finally, on the third try, the lab techs solved this gnarly variation on The Goldilocks Problem (dentures and porridge!) and we were off to make the best-fitting denture made at Penn Dental that year. Yes, I am convinced of it.

Dr. Byron Kern was a gentleman and a gentle man. He knew the science and the art that forms the foundation of our field, and understood the art of dealing with human beings in a respectful and goal-oriented manner. He also knew the value of laughter- how it healed, how it helped get a patient through a complex course of treatment. I thank Dr. Kern for teaching me the value of striving to create something that fits exceptionally well. I thank him for all the things he taught me. 

And for the Frisbees.

Memorial Day Post: Captain Ben L. Salomon

Thank you to all who have served, from our Revolution to the present day. And particular thanks this day to Captain Ben L. Salomon, September 1, 1914 – July 7, 1944, who posthumously won the Congressional Medal of Honor "For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty." He saved more than 30 wounded American's lives at the cost of his own. To my knowledge, he is the only dentist ever to have received our country's highest military honor.

http://en.wikipedia.org/wiki/Ben_L._Salomon

Composite Resin Longevity

There are still rumblings in some quarters about how composite resin restorations don't work very well, don't last very long, and get all kinds of recurrent cavities underneath them. 

First of all, it's dental amalgam (which dates from at least 1833 in the U.S.) which fails from the inside out. Composite resins usually have the excellent feature that if they fail, it's from the outside in. They give us notice.

More on dental amalgam here, if interested:

http://rickwilsondmd.typepad.com/rick_wilson_dmds_blog/2009/11/amalgam-politicians-and-all-the-pink-trees.html

Composite resins can be extraordinarily successful if the enamel and dentin are treated properly. For back teeth, this requires the use of self-etching primers, careful placement of flowable composites as first layers that intimately adapt to the dentin, placing increments of the main composite so as not to let curing stresses pull the materials away from the surrounding tooth structure, and finally a great wedging and contouring system.

More here:

http://rickwilsondmd.typepad.com/rick_wilson_dmds_blog/2010/11/enamel-bonding-dentin-bonding.html

Let's look at a practical example.

These three restorations were placed six years ago, in 2007. For various reasons my patient has not elected to restore the center tooth with a crown, which, speaking ideally, is indicated. The support pins show at the surface intentionally, because the material is less likely to break that way, at least according to one study.

Six years. No recurrent decay, no symptoms, no root canal necessary, reasonable wear of the restoration surface. And yes, a sample size of one is merely anecdotal evidence. So I read the literature and also watch hundreds, perhaps thousands, of these restorations year after year in my practice and can never blame problems directly on the materials themselves. It's either me, or the patient if they have poor oral hygiene and excessive sugar intake in their diet. Even then, if there are new cavities, they form beyond the composite resin restoration, on the root surface. 

The materials we used were:

Bonding agent: SE Bond

Flowable composite Resin: Flow-It

Composite Resin: Heliomolar

Matrix: Bitine Ring

This system works because the best self-etching primers work. I'd only use two brands as of 2012: SE Bond from Kuraray and Prelude SE from Danville Engineering. These two products minimize problems including transudation issues, which means water moving up from the dentin in the tooth and pushing bubbles into the resin-tooth interface, weakening the bond. This is kept to an absolute minimum with these two products.

Thus, so far as I can tell, in practical terms, this restoration is as fine at the five year point as it was when I placed it.