Equine Veterinary Dentistry - from the Bronze Age to the 21st Century

Last week Jenquine were one of the sponsors for a 5-day equine veterinarian training course at Equine Veterinary and Dental Services in Grafton, and we were lucky enough o be there in person. The course was led by Dy Oliver Liyou, along with visiting professors and the outstanding experienced EVDS staff and tutors, now running for over 16 years to more than 600 equine veterinarians. From essentials through to advanced dentistry, these workshops carry on the tradition of equine dentistry, that began in the Bronze Age.

Horse dentistry was developed by nomadic pastoralists living on the steppes of Mongolia and northeast Asia during the Late Bronze Age, in response to the use of a metal bit. By increasing horse survival and reducing behavioural and health issues caused by horse equipment, innovations in equine dentistry improved the reliability of horseback riding for ancient nomads. However, many of the procedures were rough, slow and tedious (brutal even) and would cause the horse to bite and kick – a sort of experimentation with dental treatments rather than sophisticated knowledge of equine dentition.

 Equine veterinary dentistry is not limited to the late 20th century, and works from the 12th and 13th century reported treatments for inflamed gums, ointments to cure loose teeth and recommendations for the use of files and floats for trimming unequal teeth. The beginning of structured written documentation about “horse medicine” occurred in the reign of Emperor Friedrich II of Hohenstaufen (1212-1250) in Italy, and in 1559

the first pre-university structured education of “scholars” in veterinary medicine was established. The first government university veterinary schools opened in France in 1762 and 1766 — both schools still exist today and in the 19th century knowledge about veterinary medicine grew rapidly, especially in surgical matters. Since many infected or traumatized teeth needed to be extracted, various options of extraction techniques and appropriate tools were developed. English equine veterinarian Edward Mayhew published “The horse’s mouth showing the age by the teeth” in 1845.

 Other veterinary pioneers of equine dental surgery were a father and son team (JH Friedrich and Karl WA Gunther), who both had excellent education in human and veterinary medicine and agriculture and became famous professors at the Hannover Veterinary School in the 1840’s. They developed almost 40 very innovative instruments for dental surgery. Published in 1879 by William H. Clarke, was another foundational book that included detailed case descriptions and reviews of the science of 'odontology'. One page in his “Dentistry of the Teeth” - chapter is headed: “Skill versus Brutality.” While floats and files can be found in numerous textbooks, the use of traditional chisel and hammer was cautioned against due to possible damage to the teeth, gums or alveolar bones. This ‘old way’ practiced from the 1600s until the 1800s by those who ‘…chiselled away without use of a speculum lacking proper sight and control and causing disastrous damage and even resulted in jaw fractures causing death of the patients…’ In 1889 an equine veterinary professor in Indiana produced “Veterinary Dental Surgery” a 256 page textbook dedicated to the comprehensive description of the anatomy, physiology, pathology and therapy of the equine dental system.

 During the 18th century, science, rather than folklore and superstition, came to the forefront and the first veterinary school opened in Lyon, France in 1762. Oral ulcerations, lip, cheek, bars of the mouth and tongue injuries caused from the bit were recognised and recorded in early veterinary literature of the 1800’s and the development of floats, gags and extraction instruments progressed. In 1805, the first report of tooth repulsion is provided by Hanover veterinary school. Veterinary education was established later in the US with the first veterinary school opening in 1875, which further advanced knowledge and available instrumentation. In 1889, we see the first reports of filling teeth, and an early indication of dentistry for the improvement of performance, when a veterinary professor in New York reduced the first lower molars so they were not in apposition with the upper molars for horses that pulled on the bit.

Dramatic changes and achievements in science and technology combined with anatomical, embryological and pathological research in the late 19th and early 20th century have changed the face and clinical practice of equine veterinary dentistry. In 1922, Ernst Joest (Professor of Pathology at the Veterinary School in Dresden) released his studies on the postembryonal development of equine molars; in 1926 Joest dedicated an important chapter of his handbook on ‘Pathology’ to dental abnormalities; in 1936 Sir Frank Colyer in England, published “Variations and Diseases of the Teeth of Animals” with more than 1000 photos, many of them equine, and in 1937 Swiss Anatomist Max Kuepfer published “Backzahnstruktur und Molarenentwicklung bei Pferd und Esel” in which almost every moment of the embryological development and structure of equine molars is meticulously documented. A dental clinic had already existed at the Vienna, Austria, Veterinary University in the 1930’s, and has continuously developed this field in equine dentistry.

One of the most amazing lives of contributors to modern equine veterinary dentistry was that of Professor Dr. Erwin Becker (1898-1978). Mechanically and technically skilled, he planned to study civil engineering after serving during WWI in the French campaign. Unable to afford to study, his uncle Helmar Dun, a successful veterinarian near Hannover, agreed to pay for his education at the Hannover Veterinary School. Helmar Dun was a cavalry veterinarian for draft horses during WWI and recognised the need for routine dental checks and hence every horse that came to his clinic was given a thorough dental exam.

In the early 20th century, dressing of teeth became a common procedure and in the mid-20th century, equine veterinarians described bit seating, improving veterinary dental care and knowledge. In 1970, a human dentist opened an equine dental facility in Switzerland veterinary faculty, and intensive equine veterinary dental courses, where experienced lecturers and professors shared their experiences with equine practitioners, increased dramatically world-wide. The mid-1990s saw an upsurge in research and knowledge of equine dentistry, primarily led by the University of Edinburgh and we are lucky to have improved power tools and diagnostic imaging techniques.

Equine dentistry is about optimising performance, mastication and, above all, the welfare of the horse. It involves consideration of the tooth, horse, equipment, intended use of the horse, diet and environment in which the horse lives and performs. It requires an understanding of anatomy, equine clinical nutrition, infectious, exotic and zoonotic diseases, general and local anaesthesia, imaging, medicine, physiology, pharmacology, pathology, radiography, sedation, surgery and systemic disease. Overall, the importance of a thorough oral examination with appropriate diagnostics and consideration for the horse as a whole cannot be overstated. Oral examination, done correctly with a light and mirrors, is essential for the accurate diagnosis of dental and oral pathology – and non-dental diagnoses and causes must be considered.

Guided by The Hippocratic oath ‘..Primum non nocere (First, do no harm), Hippocrates (circa 460–377 BCE)..’ our true mission as veterinarians is to help prevent disease and protect the welfare of the horse. Increasing amounts of research allow equine veterinarians to base our techniques on evidence-based medicine rather than folklore and anecdotal information. Training for many years, equine veterinarians are uniquely placed and now — thanks to Dr Oliver Liyou, his peers and colleagues – highly skilled in the long history and 21st century practice of equine veterinary dentistry.

EQUINE CLINICAL NUTRITION
Dr Jennifer Stewart