When making treatment or surgical plans in medicine you always have to have a contingency plan, or two, or five. I say medicine because I do not think this is exclusive to veterinarians, I am confident that human doctors experience this as well. You can have a Plan A Gold Standard, “this is what the textbooks say should work” plan but you had better have a Plan B, Plan C, and maybe a Plan D for good measure. There are few areas where this is more necessary than with dental extractions. I’m not sure if human oral surgeons experience this to the same degree that equine veterinarians do. Sometimes in equine dental planning, you need the whole alphabet of plans.
Why is that? Let us look at all of the different factors:
Horses have (mostly) hypsodont teeth that slowly erupt over their lifetime. This means that each different stage of their lives they have different amounts of tooth hiding under the gum line, into the jaw bone or sinus cavities.
I won’t get into the development of horse teeth from embryo to adult – that would take too long. You’ll just have to believe me that the teeth are made up of different materials all folded together. Sometimes during development, there can be pockets in the teeth that didn’t fill in properly – making a section of the tooth that is weaker than the rest, one that might not show up until that portion of the tooth erupts sometime during adulthood and is then at risk of fracture.
In order to keep these teeth healthy they have live pulp horns that travel the length of the tooth, from just below the grinding surface down to the roots. These pulp horns can be a highway for bacteria that would love to set up an infection in the root of the tooth.
Depending on the horse’s age that root could be anywhere from just below the gum surface (very old) to just under the skin of the jaw (very young lower jaw) or deep in the sinus cavities (very young upper jaw).
So now you have to get a tooth out – why? Is it fractured? Diseased? Infected? Did it grow in the wrong place? If it has fractured, how much tooth is actually exposed that you could potentially grab with a tool? If you can’t grab it, how are you going to pull it out? If it is fractured, it is weakened, will you be able to get all of the tooth or just parts of it? If it is infected how far has the infection spread? Into the sinus? Into the surrounding bone? You don’t want to go pulling on a tooth which then disturbs an infected jaw bone and causes a jaw fracture! If the sinus is infected it will need to be flushed and you will need to make sure that food and bacteria from the mouth can’t get up into the sinus once you take that tooth out, opening up a tunnel. What does the root look like? Sometimes even with normal development the roots splay outward and the tooth is wider at the root than at the chewing surface! It’s like the childrens matching game – the star shaped peg can’t go through the square hole!
Thankfully, we have a lot of different techniques and approaches to achieve the desired outcome. Radiographs have helped immensely in surgical planning so that we know what we are getting into before we start, for the most part. However, the reality is that sometimes you don’t know exactly what the tooth is going to do until you start and you need to have those back up plans in place in case Plans A, B, or C don’t work! I know I have overwhelmed people when discussing the plan for their horse’s dental extraction but I think it is so important for everyone to understand that if Plan A works, GREAT, if it doesn’t, we have a plan for that too!