H&C

5
Mar
2011

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Case study: Parrot mouth meets horse dentist

Polly's mouth showed a severe overbite

Bill Lomas trained as an equine dental technician in the US before setting up his own business in the UK. Since its incarnation, his practice has continued to grow, and his reputation has spread widely. Here he shares the touching story of Polly, a mare who Bill found in a sorry state.

"Polly is a well bred seven year old thoroughbred broodmare who to my knowledge, has bred two foals. I first saw her whilst working on some horses at a dealing and livery yard. I caught a glimpse of this scrawny little horse in the corner of a stable, and for a brief second I thought it was a donkey. Her body was so weak and frail, but her eyes were so bright and her ears pricked forward.

From just looking at the shape of her muzzle, it was obvious that she had severe overbite, or parrot mouth, as we call it. I mentioned this to the dealer, but she seemed more concerned about whether the mare would get in foal when she was next covered.

Parrot mouth, a genetic dental disorder, is poor head conformation and often easily identified by the shape of the muzzle. Parrot mouth occurs when the upper jaw is longer than the lower jaw causing the upper front teeth (incisors) to overshoot the lower front teeth, making it very difficult for the horse to graze or nip the grass. In severe cases, it can be impossible for the horse to graze.

The distance of the mismatch of the front teeth will be the same distance as the mismatch of the molars at the back on the mouth. A normal horse's mouth is naturally designed to crop the grass with the front teeth, then feed it back to the cheek teeth (molars) to grind and crush in a figure eight motion, until ready to swallow for digestion.

The 36 teeth work together in occlusion (the upper and lower teeth coming together when the mouth is closed), erupting at the same rate as they wear down.

I asked the dealer if she minded me having a quick look at Polly. I was appalled that a horse had been allowed to get into that state - her jaw was in total gridlock - and when I left the yard that day, I was very upset.

In Polly's case the grass needed to be at least four inches long so she could clamp the grass with her lower incisors and the hard palate. Only 20 of her 36 teeth were in occlusion. The remaining 16 teeth were unopposed (malocclusion) and had continued to erupt at a fast rate. This would eventually have caused mayhem to the whole of the mouth and I think Polly would have been an example of death by dentition through starvation.

After two sleepless nights of not being able to get Polly out of my mind, I plucked up the courage and left a message at the yard offering meat money for the mare. I paid £200 for her so as I could take her home and work on her mouth and also take her out of the breeding circuit.

When I work on a horse I usually start at the back of the mouth and work my way out, but in Polly's case I had to work my way in through large focal overgrowths to find teeth part embedded in her tongue, and inside cheek ulcers all over her mouth.

I have done around seven hours work on her so far. It is crucially important that the work needs to be done gradually in one hour sessions, as to reconstruct and release the jaw instantly could be fatal - the jaw muscle would not be able to cope with the new jaw and the horse has to learn how to eat again. You only have to look at the pictures below to see what good progress she is making.

The full mouth speculum (gag) needs to be specially adapted for parrot mouth using a designed upper bite plate softly padded to sit in roof of mouth making it easier for the dentist and comfortable for the horse. I have about another two hours work to do on Polly in the next couple of months. After that she will need to be looked at every six months for routine maintenance. The teeth have now been realigned by around an inch, so Polly finds it much easier to eat, and is putting weight on well.

Polly has been exceptionally good throughout this experience and has required no sedation at all. Her eyes, which were what attracted me to her in the first place, have remained bright throughout, and she always has her ears pricked. She seems to enjoy me working in her mouth.

Amazingly, she loves people, and I am planning on taking her with me on some of my lecture demonstrations to show people what a difference we can make. A parrot mouth does not have to condemn a horse; with good management and routine dental maintenance, they perform as well as any other.

My wife Emma and I are now long reining Polly ready for backing, and we hope to make a nice riding horse of her, with a view to perhaps finding her a nice permanent loan home to secure her future."

Find out more about Bill Lomas by reading his biography.