Maintaining healthy tusks in captive Pacific walrus (Odobenus rosmarus divergens) has been challenging for many institutions. The wear and trauma associated with these animals’ captive behavior of grinding their tusks on exhibit rocks, cement block walls, etc., has been thought to be a contributor to the tusk pulpal problems that affect these animals. A technique of placing (and replacing as needed) sacrificial metal crowns on Pacific walrus tusks has been effective in slowing the wear of the tusks and allowing tusk growth.
An impression of the tusk tip is made with alginate dental impression material and a stone model is poured. This technique requires the animal to be trained to remain relatively motionless for 1.5 minutes. An alternative technique for those younger or less-trained animals is the use of warm modeling clay in a specimen jar. A light layer of mineral oil is placed on top of the clay and the specimen jar is then forced over the tusk and removed immediately in a parallel path with the tusk to minimize distortion. Since most tusks have almost an ideal crown preparation taper, no tusk preparation is necessary (an occasional undercut can be blocked out in the lab). Crowns are then fabricated out of a removable partial denture material (Ticonium). The crowns can then be tried on the tusk for fit and placed with glass ionomer cement without anesthesia. Depending on the aggressiveness of the tusk wearing habits of the animals, the crowns have been reported to last for 6–12 months (or longer) before they wear through and need replacement.