Researchers' understanding of how bits and horses' mouths interact is far superior than that of decades ago, but the ideal combination of factors to keep bitted mouths healthy remains just out of reach. According to one equine veterinarian and dentist, however, using gentle hands and bit seats--among other elements--can contribute to a healthy equine mouth.
At the American Association of Equine Practitioners Focus on Dentistry meeting, held Sept. 18-20 in Albuquerque, N.M., Jack Easley, DVM, MS, Dipl. ABVP, a private practitioner from Equine Veterinary Practice LLC, in Shelbyville, Ky., discussed the age-old question of how to best keep a horse's mouth healthy if he wears a bit frequently.
Historical Perspective on Bit Seating
"Oral ulcerations and injuries caused from the bit were recognized and recorded in early veterinary literature," Easley explained. "These were first thought to be caused from the bit pulling the oral soft tissues against sharp enamel points on the cheek teeth."
He relayed that in the past sharp cheek teeth have been blamed for numerous problems including bad behavior, "lugging out," and even some lamenesses. He also discussed research that points to improper (harsh) use of the bit as causing some bitting problems.
"More than 100 years ago, Mayhew1 described injuries caused from the harsh use of the bit in the lip commissures (the corner of the mouth), cheeks, tongue, bars of the mouth, and chin groove," he said. "He recognized early on that all these injuries were not attributable to sharp tooth points."
In the early 1900s, Easley explained, veterinarians began to use the practice of "teeth dressing" on a more regular basis. This procedure entailed using a rasp to dull the sharp enamel points on horses' teeth and "rounding up first superior and first inferior molars" to create a seat for the bit. Not long after, the modern art of bit seating got its start.
"In the mid-20th century, equine veterinarians and tooth floaters described bit seating as the rounding of the first cheek teeth to reduce enamel points and contouring the teeth to decrease cheek pressure and injuries from the bit," Easley said.
He explained that previous research indicated rounding off the buccal (cheek side) and occlusal (chewing) surfaces of the upper molars and the lingual (tongue side) and occlusal surfaces of the mandibular (lower jaw) cheek teeth in addition to the front occlusal surfaces of all four first molars would help reduce potential discomfort induced by the bit. Further, he noted, additional studies have shown that smoothing and shaping the molars located furthest back in the horse's mouth can allow for a more comfortable and relaxed lower jaw.
Another consideration veterinarians need to take into account when floating teeth of bit-wearing horses are the wolf teeth, Easley said.
"The fact that these vestigial (almost useless) teeth do not serve a purpose and may possibly cause discomfort and training issues has resulted in the common practice of extracting wolf teeth," he explained. "Sharp wolf teeth may cause buccal ulcerations and pain when the noseband or bit forces the soft tissues into these teeth."
Easley then discussed some scientific research carried out examining the relationship between bits and equine dental health.
"Studies2 have shown a high incidence of oral ulcers in bitted horses as compared to horses not ridden in bit and bridle," he explained. "A more recent study supported the time-held beliefs that the standard practice of floating teeth to reduce sharp buccal and lingual points (without bit seating), is not effective in preventing oral ulcerations in ridden horses."
Further, he noted that a clinical study3 on 20 horses showed an "improved trainer perception of athletic performance and responsiveness to the bit after dental floating and bit seating," while a later study showed no positive effect on dressage scores post-floating.
Easley also noted that professionals should take care when using motorized dental equipment on equine teeth, as some studies indicate pulp damage is possible even if direct contact doesn't occur. Pulp damage in equine teeth can lead to a host of dental problems down the road.
Where Do We Stand?
So what does all this information indicate about the benefits--or lack thereof--of bit seating?
"The incidence of buccal ulcers can be quite high in horses ridden with bit and bridle," Easley began. "Removing sharp enamel points on bitted horses without contouring the front teeth will not prevent oral ulcerations opposite (some cheek teeth) and in the lip commissures. Further studies need to be performed to determine the effects of rostral contouring (bit seating) on the incidence of oral ulcerations in the bitted horse."
Easley also suggested that some responsibility for keeping the bitted horse's mouth healthy lies in the hands of the rider--quite literally.
"Such findings and clinical evidence has led some to feel strongly that the bit is inhumane, and it certainly is, in untrained hands," he noted.
He also suggested some ideas from past researchers to help minimize the risk of oral ulcers.
"Merillat (1915) mentioned bit gnathitis (jaw inflammation) and recommended better mouthing or bitting practiced by the trainer rather than more dentistry," he said. "Merillat agreed with recent recommendations ... that alternating days in training with a broken snaffle and straight bit and using a lighter hand will remedy most problems. Training in a bitless bridle or hackamore is another practice recommended to reduce or alleviate bitting injuries."
1Mayhew E. The illustrated horse doctor. Philadelphia: JP Lippincott Co 1888;64-72.
2Allen TA. Incidence and severity of abrasions on the buccal mucosa adjacent to the cheek teeth in 199 horses. In Proceedings, Am Assoc of Equine Pract 2004;50:31-36.
3Wileuska KA, Rubin L. Bit seats: A dental procedure for enhancing performance in show horses. Equine Pract 1999;21:16.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.