VN January 2023

Vetnews | January 2023 35 The clinic is often contacted for advice regarding maxillary 4th premolar (carnassial) tooth fractures. Apart from the canine tooth, this is the biggest tooth in the maxillary arcade. Together with the maxillary 1st premolar tooth and the mandibular 1st molar tooth, it forms the carnassial apparatus. This apparatus is very effective when carnivores need to crunch or break anything they can get that far in their mouths. Bite force measured at the carnassial teeth is 330 – 1100 N (depending on the breed, Kim SE, et al., 2018). When a dog bites down on a very hard object (like a bone or cow hoof), the forces generated on the carnassial teeth will either overcome the structure of the object and break it, or the force may shear a part of - or fracture the tooth. Due to this, I do not advocate the use of bones or cow hooves for dogs. Dogs may present with a sagittal slab of tooth still in place, which usually extends below the gingival margin (Fig. 1). On clinical examination in the awake dog, it would not be easy to evaluate pulp exposure. The presentation can also be more obvious with the sagittal slab of tooth lost from the oral cavity (Fig. 2). In these cases, it is easier (depending on the amount of calculus on the tooth – i.e. chronicity of the fracture) to see if the pulp is exposed or not. Figure 2. A sagittal (slab) fracture of a right maxillary 4th premolar tooth. The slab is not present anymore, and the large pulp opening is clearly visible. Calculus has already accumulated on the tooth, suggesting an older fracture. In acute fractures (1-2 weeks), the pulp might still be bleeding or have a red colour to it. Older fractures are usually darker in colour due to necrosis of the pulp. What to do with the dreadedmaxillary carnassial tooth? Dental Column Prof. Gerhard Steenkamp Figure 1. A sagittal (slab) fracture of a left maxillary 4 th premolar tooth. The slab is still in place, and it is not possible to know if the pulp is exposed. A draining tract opened at the gingiva-mucosal junction. Figure 2. A sagittal (slab) fracture of a right maxillary 4 th premolar tooth. The slab is not present anymore, and the large pulp opening is clearly visible. Calculus has already accumulated on the tooth, suggesting an older fracture.