FIND OUT WHY
Dogs deserve the same straight, engaging smile we humans seek, right? OK, that may be stretching it a bit, but what our patients do deserve is a bite that’s comfortable. This article highlights the classes of malocclusion in dogs. Future articles in this series will address individual cases that fall into these classes and show what can be done using both common and uncommon techniques to resolve problems.
Photo 1: Normal occlusion of the incisors in a dog.
Although preventing permanent teeth malocclusions is ideal, most of the cases veterinary dentists encounter consist of traumatic tooth-on-tooth or tooth-on-tissue disease in an adult patient that might otherwise have been prevented. Many patients present with severe tooth wear, fractures, endodontic disease and trauma to the palatal and lingual floor soft tissue or bone. So knowing normal anatomy is the first step in recognizing abnormal occlusions that can progress to more serious disease.
The American Veterinary Dental College (AVDC; www.avdc.org) describes dental malocclusions as follows:
Photo 2: Normal occlusion of the canines in a dog.
Photo 3: Normal occlusion of the premolars in a dog.
Three classes of symmetrical malocclusions occur in dogs.
Photo 4: A class 1 malocclusion.
Neutroclusion (Class 1 malocclusion; MAL/1): Jaw lengths are normal, but one or more teeth are in an abnormal position (Photo 4). Examples include lance canine, rostral crossbite, caudal crossbite and level bite.
Mandibular distoclusion (Class 2 malocclusion; MAL/2): The mandible resides distal (caudal) to its normal location in relation to the maxilla (Photo 5). This often results in mandibular canine teeth traumatizing the palate.
Photo 5: A class 2 malocclusion.
Photo 6: A class 3 malocclusion.
Mandibular mesioclusion (Class 3 malocclusion; MAL/3): The mandible resides mesial (rostral) to its normal location in relation to the maxilla (Photo 6). Although considered normal in brachycephalic breeds, maxillary incisor contact with the lingual floor or canine teeth can cause significant trauma and discomfort.
According to AVDC, maxillary-mandibular asymmetry describes skeletal malocclusions in dog that can occur in one of the following directions:
Rostrocaudal: A MAL/2 or MAL/3 malocclusions in dog is present on one side of the face while the contralateral side retains normal dental alignment.
Side-to-side: Loss of the midline alignment of the maxilla and mandible.
Dorsoventral: Results in an open bite, defined as an abnormal vertical space between opposing dental arches when the mouth is closed.
Wry bite is a nonspecific layman’s term used to describe various unilateral occlusal abnormalities, so its use isn’t recommended.