Dental-crown alloys -
There are 3 kinds.
In general, there are 3 basic categories of dental alloys that can be used. They are: high noble, semiprecious, and nonprecious. This classification system is based upon the metal's composition.
Each is different.
Each type has its own specific advantages and disadvantages, including: cost, insurance coverage, color (yellow or "white"), as well as general physical properties.
This page discusses each of the above considerations. However, if cost is not a factor, the alloy having the highest precious metal content typically makes the best choice.
Crowns that have a metal component (all-metal and porcelain-fused-to-metal ones) are made using specific types of alloys. No pure metals are used, not even gold. This is because for dental applications, the physical properties of alloys are superior.
Here's the formal classification system that is used to categorize dental alloys.
1) High noble alloys (Precious metal)
This group has a composition that is over 60% noble metal (gold, palladium and/or platinum), of which more than 40% must be gold.
These metals constitute the "gold standard" of dental alloys; all others are compared to them. High noble alloys are the easiest type of metal to work with (for both the dentist and dental laboratory) and create the most predictable bond with porcelain.
2) Noble alloys (Semiprecious metal)
These alloys have a noble metal content that is, at minimum, over 25%.
3) Non-noble (Nonprecious metal)
Why should you care what alloy is used to make your crown?
There are several reasons why you should care what metal is used. Some of them will affect you directly. Others will be more of a concern to your dentist, or the dental laboratory that makes your crown.
a) Costs - High noble metal alloys cost more.
The "noble" dental metals are gold, platinum and palladium.
Nowadays these metals are pricey. And the greater the percentage of them found in the composition of an alloy, the greater its cost will be.
With some applications, the overall price difference between using a high noble or base metal alloy might be small. But in the case where an all-metal crown is made for a large molar, it might be a factor in which you choose.
b) Dental plan and insurance policy limitations.
If some type of dental plan is paying a part of your bill, you might check to see if there are any limitations as to the type of metal that can be used for crowns.
The policy might state that they do not cover the cost of high noble alloys. Or the level of coverage might change based on which type is used.
This gold crown has a yellow color.
c) Color - Dental alloys can be white or yellow.
In those cases where an all-metal crown is being placed, you might have a preference as to whether it should have a yellow (like gold) or silver ("white," white gold) coloration. The alloy's composition determines its color.
d) Some people have metal allergies.
Studies report that about 10% of the female population and 5% of males have an allergic response to nickel, chrome and/or beryllium. These metals are often found in the composition of nonprecious (base) alloys.
A porcelain-fused-to-metal dental crown (the metal is "white").
e) The physical properties of the alloy are an important consideration.
Dentists and dental laboratories often have a set opinion about which types of dental alloys they will consider working with. This is because their goal is getting the job done right, the first time.
They know that any difficulties or problems experienced will just end up costing them money. So, if choosing a certain type of alloy makes getting a positive result more likely, then that's the one they are probably going to want to work with.
The advantages of precious dental alloys.
In general, dentists and dental labs prefer to work with high noble alloys. These metals are easiest to cast, provide the most accurate fit on the tooth, offer some degree of malleability (so the fit of the metal can be adjusted, if needed), and offer the most predictable bond with porcelain.
Which type of alloy should you choose for your dental crown?
As mentioned above, assuming that cost is not a factor, high noble dental alloys makes the best choice.
Full menu for topic Dental Crowns -
- Dental crown ("cap") basics - What are they? When is one needed?
- Applications / Advantages -
- The steps of the dental crown procedure.
- Common problems and complications.
- How to sell old crowns.
- Assorted FYI facts about dental crowns.