Which teeth are the canine carnassials in dogs, and why are they clinically important?

• A. Lower P3 and upper M2; essential for grinding.
• B. Upper P4 (maxillary fourth premolar) and lower M1 (mandibular first molar); essential for shearing and commonly affected by fractures or disease due to high occlusal loads.
• C. Upper canine tooth and lower incisor; only for aesthetics.
• D. Lower P4 and upper M1; not carnassials.

Answer: (B)

Carnassial teeth are the primary shearing teeth in dogs. In this species, they are the upper fourth premolar (P4) and the lower first molar (M1). Their cusp shapes and alignment create a sharp cutting plane when the jaw closes, allowing a slicing action that efficiently shears meat rather than grinding it.

Their clinical importance comes from bearing the highest occlusal forces in the dental arcade. That heavy loading makes them particularly prone to problems such as fractures from trauma or chewing hard objects, and to periodontal or endodontic disease once damage permits bacterial invasion. Clinically, problems with these teeth can lead to pain, altered chewing, and appetite changes, and they often require careful radiographic assessment to evaluate for root fractures, periapical pathology, or bone loss. Because of their critical role in chewing, preserving them when possible is beneficial, but severe damage may necessitate endodontic therapy or extraction. Other teeth do not form the primary carnassial pair and are not responsible for this slicing function.