Originally published on TheHorse.com
When discussing our dental health, we are familiar with commonly used terms such as plaque, cavity, or root canal. But discussing our horses' teeth can be a bit more confusing: Mesial. Occlusal surface. Interproximal space. What does it all mean? Fortunately, at the 2013 Western Veterinary Conference, held Feb. 17-21 in Las Vegas, Nev., Cleet Griffin, DVM, Dipl. ABVP, a clinical assistant professor in the Texas A&M University College of Veterinary Medicine and Biomedical Sciences, reviewed the basics of equine dental anatomy, beginning with common terms and their definitions:
During his lecture, Griffin described some interesting and important points to remember about horse teeth.
He explained that horses have hypsodont teeth, meaning they have long crowns divided into two regions: the clinical crown (the short length visible in the mouth) and the reverse crown (the longer portion located under the gums). The reverse crowns are situated in sockets called alveoli, he said, and the surrounding gum prevents feed from accumulating in tiny gaps between the teeth and the alveoli.
"An important anatomic concept to remember is that the horse is anisognathic, which means the upper and lower jaws are different widths," Griffin said. The maxilla (the upper jaw or cheek) is about 30% wider than the mandible (the lower jaw), and the maxillary teeth are slightly wider than the mandibular teeth, he said.
"The differing width of the jaws and the chewing motion of the horse leads to formation of sharp enamel points along the buccal edge of the upper cheek teeth and the lingual edge of the lower cheek teeth," Griffin explained. "These sharp areas can cause discomfort to the horse when eating or when bridled and working."
Horses' cheek teeth (the premolars and molars) are tightly wedged together to prevent feed from compacting in the interproximal areas, Griffin explained. Additionally, each row of cheek teeth has an angled grinding surface (generally about 10 to 15 degrees) to help break down feedstuffs, he said.
Horses' teeth grow and erupt continuously throughout their lives, generally at a rate of two to three millimeters per year, Griffin explained; this continues until the horse has aged into his 20s. This continuous tooth growth is needed to counteract dental wear resulting from "long hours of consuming tough, fibrous feedstuffs," he said.
Griffin explained that young horses develop and erupt 24 deciduous (or baby) teeth, including the incisors and premolars. Starting at about one year of age and continuing approximately through age five, horses sequentially erupt 36 to 44 permanent teeth, including incisors, canine teeth, wolf teeth, premolars, and molars. "The total number of permanent teeth depends on the presence or absence of canine teeth and wolf teeth," Griffin noted.
Griffin reviewed how the horse's teeth are organized within the mouth:
While equine dentistry can be complicated, having a basic understanding of dental anatomy and terminology can help owners better comprehend this complex and important topic.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.