Evaluating Occlusion of the Incisor Teeth (Prior to Speculum Placement)
● When the horse’s mandible is in a centric po- sition, normal occlusion between upper and lower incisors when viewed frontally is a level bite.
● When the profile of the incisor teeth is exam- ined, the labial edge of the upper and lower incisors meet evenly in normal occlusion; how- ever, this is somewhat dependent upon head position in that the mandible retracts when the poll is extended and protrudes when the poll is flexed.
● Lateral excursion can be assessed to document the extent of molar occlusion using the meth- ods of Rucker.7
Evaluating Occlusion of the Cheek Teeth
● The horse’s anatomy results in a sloped chew- ing surface with enamel points on the buccal aspect of the upper cheek teeth and the lingual aspect of the lower cheek teeth.
● The mandible and maxilla have differing width (anisognathia), and the mandibular cheek teeth appear slightly more narrow than the maxillary cheek teeth.
● The rostral portion of the left and right upper rows of cheek teeth curve slightly toward midline.
● There is a normal upward curvature of the occlusal surface of the caudal aspect of the upper and lower dental quadrants (Curve of Spee).
Fig. 2. A, Extraoral finding: bony swelling associated with non- vital teeth (arrows). B, Extraoral finding: nasal discharge associ- ated with secondary dental sinusitis. C, Extraoral finding: draining tract on a mandible associated with a nonvital Triadan 307.
Descriptions of Malocclusion
There are several descriptive terms for malocclu- sions in the horse. Malocclusions are often de- scribed when there are overlong portions of the
