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Prosthodontics - Crowns (Metal and white)
Working dogs – mainly Police, Military and Search & Rescue dogs – have been having crowns fitted to root filled fractured teeth for some time. These animals require the use of a full length metal crown to contunue working. We will recommend the use of a crown if it is te only way of protecting a vulnerable tooth from fracture damage.
Currently we use Talladium Tilite as we feel it provides excellent strength, superior bonding to the tooth and a good appearance. These metal crowns are strong and durable but they do make the dog look fierce! White crowns are possible in some circumstances - see below. They look more natural but do not have the strength yet to be used in canine or carnassial teeth. Technology improves all the time and we monitor this One major restriction is the need for at least 4mm of tooth to attach the crown to. If we have less than this it can make keeping the crown on a real challenge.
This left lower canine was badly fractured but the pulp was not exposed. A full metal crown will protect it from further damage and the subsequent need for root canal treatment. The tooth is "prepped" to accept a crown so it is no wider than the undamaged tooth. Impressions arer taken for a lab to fabricate a custom crown. In the meantime a temporary crown is placed to protect it for the two weeks in between visits.
The Talladium tilite crowns are delivered back to us on custom stone models of the original impressions and are ready to place. The temporary crown is removed and the tooth cleaned.
The crown is trial fitted to ensure it covers the prepped tooth without any defects and also to ensure te mouth will close without any abnormal contact with the upper teeth.
Low gold alloy crown ready to fit to an upper carnassial.
Some vet dentists advocate the use of a post to improve retention. Whilst this helps it can also increase the strength of the crown to the point where, under hard biting stress, the dog may severely fracture the remaining cropwn or even pull the whole tooth out of the socket - rather than just lose the crown
White Crowns
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In the last few years we have been able to obtain white crowns made from Zirconium. or Lava Rock. These are not as strong as full metal crowns and we do not place them on canine or carnassial teeth currently. There has been a recent trend to do so but long term reports are not encouraging. CaniZ is a milled zirconia restoration which may hold promise for the future - see http://www.pcdl-usa.com/veterinarians/
Fractured upper right incisor (202) following root canal work. Tooth now stable but not good enought for show purposes
Same tooth with zirconium crown placed
Partial Crowns and Onlays
Another application for the protection offered by crown is for teeth damaged by heavy abrasion such as Cage Biter Syndrome (CBS). This syndrome is common in Police and other workiing dogs (e.g. guard dogs) that spend time in cages during work. They grip the cage bar or fence wire with their canine teeth and rub up and down. It is cosidered a behavioual vice and is hard to stop. The result is heavily worn canine teeth, mainly on the distal aspect, and eventual fracture and pulp exposure due to the weakness.
Crown damaged by Cage Biter Syndrome
Partial onlay to protect tooth from fracture
Metal onlays can help protect the teeth before they fracture. The worst case of this we saw was an explosive sniffer dog that was bound for the Falkland Islands with the RAF. In his two year tour of duty he managed to wear through the titanium crowns to the absolute disbelief of the dental laboratory!
| Common case types |
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Click the following links for more details on the most common referral case types. |
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