Hi. My first lower molar has a large, @20yr old amalgam filling. I'm keen to protect it from possible fracture/decay. My dentist has suggested a crown but without removing the old filling. Is this a wise and usual course of action? The filling isn't obviously cracked but it there is a gap between it and the tooth. Thanks for any advice. Martin
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Crown over old filling
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2 UpVoted this answer
Have the dentist remove the amalgam. A small gap for you is the grand canyon for bacteria. Amalgam restorations block x ray beams so if you are developing decay the dentist won't be able to see it until it is too late. Remove the entire restoration and place a new one followed by the preparation for the crown. If you are near Oxon Hill MD stop by for a complimentary consultation and I'll take a look at it.
Peter Merai DDS, FAGD
Peter Merai DDS, FAGD
2 UpVoted this answer
I would remove the old filling entirely. Fillings shrink over time (referred to in dentistry as "creep"). This allows leakage into the filling, which allows bacteria to get inside the tooth. The durability of a leaky filling is questionable. Removing the old silver will allow the opportunity to clean any cavities that formed. The silver filling should be rebuilt with resin composite (or in layman's terms "tooth-colored filling"). Unlike silver, tooth-colored filling actually sticks to the teeth.
The risk with keeping the old silver is it could displace at anytime and could destabilize your new crown. In my practice I never leave silver on a tooth being restored with a crown. Your crown will have a better chance of fitting for a long time if the silver is replaced.
The risk with keeping the old silver is it could displace at anytime and could destabilize your new crown. In my practice I never leave silver on a tooth being restored with a crown. Your crown will have a better chance of fitting for a long time if the silver is replaced.
2 UpVoted this answer
The most common reason for replacement of all types of restorations in permanent
and primary teeth is recurrent caries. Recurrent caries, also know as secondary decay would be highly suspect in a 20 year old amalgam filling. Prior to placing a crown, it is critically important to insure that no bacteria reside in the underlying tooth structure. The only definitive way to verify this is to remove the old filling, disinfect the tooth and replace it with a new restoration.
and primary teeth is recurrent caries. Recurrent caries, also know as secondary decay would be highly suspect in a 20 year old amalgam filling. Prior to placing a crown, it is critically important to insure that no bacteria reside in the underlying tooth structure. The only definitive way to verify this is to remove the old filling, disinfect the tooth and replace it with a new restoration.
2 UpVoted this answer
Amalgam fillings should be replaced about every 10 years so you are way overdue in having that filling completely removed. Micro-leakage at the interface between filling and tooth cause bacteria to invade that space that can lead to recurrent decay. Sometimes a sound filling is not completely removed during crown preparation but that is a matter up to the clinical judgment of your provider.
1 UpVoted this answer
Dental crown over an old filling is not a good practice, I personally like to take all the fillings out, make sure there is no caries, then build up tooth with dental composite and after place your porcelain crown. There is possibility of recurrent decau under old mercury fillings!
Since you have been protecting the tooth for such long time, and I believe you want to be conservative, the least invasive dentistry it is the best dentistry, ask your good dentist if you can have porcelain inlay onlay rather than porcelain crown, it is less invasive and your tooth does not need to be cut 360 degrees.
You can read inlay onlays vs dental crown in my website!
Best of luck to you!
Since you have been protecting the tooth for such long time, and I believe you want to be conservative, the least invasive dentistry it is the best dentistry, ask your good dentist if you can have porcelain inlay onlay rather than porcelain crown, it is less invasive and your tooth does not need to be cut 360 degrees.
You can read inlay onlays vs dental crown in my website!
Best of luck to you!
1 UpVoted this answer
In my experience, large amalgam fillings are the most common reason why a tooth would need a crown since they expand and contract with hot and cold temperatures and many times introduce stress fractures into the tooth that then cause cusp fractures. With that being said, if a crown is indicated on this tooth and there is a gap between the amalgam and the tooth, I think it may be warranted to remove the amalgam first and clean up any recurrent decay around it. A composite buildup would most likely be necessary afterwards to replace missing tooth structure before the crown preparation. Sometimes it is possible to prepare through the amalgam, but most of the time I prefer to remove it to make sure the underlying tooth structure is in good shape without any recurrent decay which could cause trouble later. I have seen many crowns break off of the tooth at gum level because the previous amalgam restoration was very large and weakened the tooth. These crowns have small amounts of tooth structure inside them with large amalgam remnants.
1 UpVoted this answer
Every case is different, but if your dentist thinks this specific situation is appropriate to leave the previous restoration in place then it probably is.
If during the preparation of the crown there is no leakage or potential visible cavities then it might be ok to leave the existing filling in place. It might also be the case that the existing filling is very deep and close to the nerve and he doesn't want to disturb it. Having said all that ideally yes everything should be removed and new restoration placed just to be sure that the crown is placed on a solid foundation.
If during the preparation of the crown there is no leakage or potential visible cavities then it might be ok to leave the existing filling in place. It might also be the case that the existing filling is very deep and close to the nerve and he doesn't want to disturb it. Having said all that ideally yes everything should be removed and new restoration placed just to be sure that the crown is placed on a solid foundation.
1 UpVoted this answer
If there is a gap between the old mercury filling and the tooth, I would remove the whole filling while paying particular attention to the pulp of the tooth. I would consider placing a Fluoride releasing liner over the pulp of the tooth if there is recurrent decay. That adds protection to the nerve of the tooth. Then do the bonded new build up on top of it. That is what i would do before the final crown preparation.
1 UpVoted this answer
If it was my tooth, I'd feel better if the 20 year old filling was removed first, to insure the tooth underneath was sound. An exception to this would be if the potential danger of damage to the tooth from removing the filling outweighed the potential danger of leaving undetected decay.