As I addressed in the July 2024 column, dogs can generate large amounts of force when they bite down on an object. When a tooth fractures, treatment includes restorative dentistry. Sometimes, prosthodontics (placement of crowns) is an important consideration for restoration and protection of the tooth. Police dogs, for example, likely put the most strain on their teeth with daily bite work and apprehending perpetrators. Plus, they are often trained utilizing bite sleeves. During training and working, large canine teeth can fracture from force and leverage placed on these teeth. However, pets can also break teeth by chewing on hard objects, such as bones, antlers, nylon toys, cow hooves, and ice cubes. In these cases, the maxillary fourth premolar receives the brunt of the trauma. When a tooth becomes fractured or worn due to forces placed upon it, a prosthodontic crown may be warranted. Endodontic options Fracture of a tooth often results in pulp exposure. Endodontic options for a pulp-exposed tooth include root canal therapy or vital pulp therapy (partial coronal pulpectomy and restoration), Total pulpectomy (root canal therapy) is usually a better option in the mature permanent tooth, since concussive pulpitis may silently fester within the remaining pulp after vital pulp therapy. In humans, nearly every tooth receiving endodontic therapy will receive a crown due to concerns of the tooth refracturing and due to the amount of tooth structure removed when gaining access to the human endodontic system. In veterinary patients, dental specialists have varying views on which patients should receive a crown to cover their endodontically treated tooth. Some veterinary dentists recommend a crown for every endodontically treated tooth. Other dentists consider it important to place a crown for every endodontically treated carnassial tooth, but not necessarily every canine tooth. It is safe to make the following generalization: if the patient will continue to be exposed to the item that caused the tooth fracture in the first place, placement of a metal crown is a good idea. Below are three real-world examples: The previously mentioned police dog that fractures its tooth while doing bite work. Bite work will certainly be a part of this dog’s future after having root canal therapy, so a crown would be a good idea. If a dog broke its tooth by chewing on something hard, and the offending item is not able to be completely removed from the environment (such as rocks). Dogs with separation anxiety that chew on cage bars, where a functionally important tooth has fractured, and a pet owner wants to save the tooth with endodontic therapy. A metal crown may protect the investment in root canal therapy by decreasing the chances of repeat fracture of the tooth. Why not place a crown on every endodontically treated or worn tooth in our veterinary patients? The two main reasons are administering anesthesia and cost. Placing crowns requires at least one additional anesthesia to cement the crown on the tooth after it returns from the dental laboratory. Another reason could be because crowns can be expensive, especially if multiple teeth are fractured or worn. There are many cases where pets may benefit from placement of a metal crown. Placement of a crown can provide a full metal jacket on top of the remaining tooth structure (Figures 1A, 1B). A titanium crown has been placed on a maxillary fourth premolar tooth (Figure 1A), and a canine tooth (Figure 1B). Photo courtesy Dr. John R. Lewis Crown preparation procedures require a steady hand and an artistic perfectionist’s mentality. The end result is a thing of beauty and functionality. Amazingly, the crowns stay in place quite well if you adhere to important considerations during the procedure. This is true even in those police dogs that test the crowns every day with bite work. Though police officers do not seem to mind the “bling” that a metal crown provides to their working dogs, some pet owners opt for a tooth-colored crown. We rarely use porcelain-fused metal crowns since more tooth structure must be removed to allow the layers of porcelain and metal to be flush with the tooth, and porcelain can chip off when repetitive behaviors put forces on the crown. Tooth-colored zirconia crowns used in humans do not always hold up to the forces that dog can generate. In some cases, it may be advisable to place a crown on a worn vital tooth to prevent further wear or tooth fracture. Dogs that chew on cage bars develop a characteristic wear pattern on the distal surface of the canine teeth, which over time, may result in a severe fracture of the tooth. To prevent this, a ¾ crown may be placed, which covers the tip, back and sides of the tooth. Extra care must be taken during the crown prep procedure of vital teeth to ensure that no excessive heat is generated (which can result in pulpitis) and only the necessary amount of tooth is removed to make room for the crown. John R. Lewis, VMD, DAVDC, Fellow, AVDC OMFS, practices at Veterinary Dentistry Specialists and teaches at Silo Academy Education Center, both in Chadds Ford, Pa.
