Re: What to do? Root canal or not?

Amatus Cremona wrote:
You are allowed to disagree with me.

Most teeth getting a crown for the first time, have thick axial walls on the buccal or lingual (or both) near the CEJ. Because the tooth tapers and becomes more narrow towards the root tip, the average crown prep removes a lot of tooth structure to get adequate thickness for the crown margins at the CEJ. You cut away the thickest part of the tooth -- a few mm coronal to the CEJ in order to get your converging axial walls to the crown prep and still get adequate reduction at the margins. If the tooth had a wide amalgam or composite through the center of the tooth, the resultant vertical wall of dentin left after the crown prep, may be very tall, but is also very thin.

A better way to restore the tooth would be to simply cut off the coronal 1/3 of the tooth, clean out the caries and old restoration, smooth the internal walls, and fabricate something which can be bonded to the inner surfaces and the top of shortened cusp tips. You would be left with 3 times more original tooth structure, and more of the inherent flexibility of the tooth would remain -- abfraction would not be localized the CEJ, but could spread out a few mm in both directions. If you bond the restoration, choose color of Porcelain and adhesive properly, and finish the margins on the tooth, the line will not be visible beyond 1-3 inches away.



I think that sometimes we are biased by the results of our own techniques. By this I mean that the clinical sequellae of what we've done in the past often reinforces our restorative decisions.
The biggest example that comes to mind to me is the use of amalgams. If we are in a fairly working class environment, proximal caries often gets restored as amalgam (or resin, but I don't have the years of experience here to comment). So after years and years of doing this, you can imagine I have seen a lot of upper premolars with old MOD amalgams where either the B or P cusps have fractured. More often than not, the fracture is close to or under the gingival margin. Even someone as thick as I am knows what this means--I have pushed the restorative material past the point at which I can reasonably expect it to work well. The result is a lot of upper premolar (and other!) crowns with subgingival margins. I may have saved patients a fee with the amalgam, but there's always a piper to be paid.
Looked at this way, your greater use of onlays doesn't look like an extravagance--it looks like a good long-term clinical decision based solely on my experience. My biggest objection is that in patients with high caries rate, I am not thrilled about giving them restoration with miles of supragingival margins. But even so, the example I've given you of the upper premolar with the too-wide MOD may very well be in a patient who is no longer a high decay risk. Clearly there is something to be said for case selection, and especially onlaid restorations in cases where I (perhaps shortsightedly) will place a large amalgam.

Steve

--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001
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