In June 2001, JADA carried Dr. Gordon Christensen’s insightful column, "Cast Gold Restorations. Has the Pendulum Swung Too Far?" (
JADA 2001;132[6]:809–11
). It specifically mentions the technique of using cast gold linguals on maxillary porcelain-fused-to-metal (PFM) crowns to reduce aggressive wear on opposing teeth.
I was somewhat surprised that Dr. Christensen’s September JADA article, "Is the Wide Range in Crown Fees Justifiable?" (
JADA 2006;137[9]:1297–9
), did not mention the impact of various designs on the quality and cost of PFM crowns, especially since the price of gold recently exceeded $700 an ounce.
Per my understanding of ADA procedure code D2750 crown—porcelain fused to high noble metal,1 dentists can use all porcelain over a thin foil of gold, a cast gold substructure covered with porcelain including the occlusal or Dr. Christensen’s above-mentioned design, which is essentially a gold crown with gold occlusion and a buccal porcelain veneer.
It is my experience that there is a significant variance in the lab costs and clinical performance of these three designs. In the last year, I have seen the porcelain-over-gold-foil design advertised for $89 via mail order, and I have had bills from my lab in excess of $350 for porcelain with gold occlusal molars (65 percent Au, 26 percent Pd). Since the goal of Dr. Christensen’s September column was to advocate for the financial welfare of the dental consumer, PFM design is important if it has an impact on longevity. Crowns that fail after a few years are not really cheaper.
Historically, all porcelain posterior crowns, especially molars, have failed at a much higher rate than gold crowns and require more aggressive preparation. Anecdotal information suggests that porcelain-over-gold-foil crowns are following this pattern.
Many dentists, including Dr. Christensen as mentioned in his June 2001 column, have chosen gold posterior crowns for themselves, and often choose PFM crowns with gold occlusals when esthetics is not a problem. These crowns do not exhibit fractured occlusal porcelain, do not wear the enamel of opposing teeth, do not destroy opposing gold crowns, require less vertical reduction (better retention, fewer root canals), are not destroyed by root canal access and are ideal for patients who brux or have poor canine guidance.
I am aware that we now have zirconia and low-wear porcelain, but I find it interesting that dentists often still prefer gold. Every year I see patients collectively spend thousands of dollars because they were not offered the judicious use of cast gold in requisite circumstances, including on the occlusals of PFM crowns. Reasons for this include the fact that insurance companies pay the same for porcelain-to-high-noble crowns, irrespective of the design, lab bills, potential longevity or ultimate cost to the patient if they fail early or damage other teeth. It could hardly be otherwise, since our own ADA dental codes don’t adequately differentiate between all of these different designs.
In the early 1980s, gold hit $800 per ounce. I briefly substituted the perennial "lower cost crown," porcelain/nonprecious. Subsequently, I witnessed numerous porcelain failures and a case of severe nickel allergy. If patients are financially strained, give them a discount or let them make payments. They deserve the same quality lab work we demand for ourselves.
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