Applying apical pressure to a tooth during an extraction is the act of pushing the tooth deeper into the socket. The tip of the tooth roots is called the apices, hence why it is called apical force.
Did we make you read that twice? Yes, you read it correctly because we really did mean it. During a tooth extraction, you should push it deeper into the jaw bone!
That probably sounds counterintuitive for you since taking out a tooth would logically tell you to pull it out from the socket instead. Well, let me tell you about the story of how I learned to use apical pressure for tooth extractions and why it is important.
During my general practice residency at Lincoln Hospital, we would periodically have rotations into the oral surgery clinic. During those rotations we would set aside our restorative dentistry skills and hone our surgical techniques instead.
There was an unforgettable moment that happened which I haven’t forgotten after all this time because I learned an important lesson.
One of my co-residents was performing an extraction on a maxillary molar (upper molar) but he was experiencing some difficulty. The tooth wasn’t budging and it appeared as if it didn’t want to come out. The attending who was nearby, noticed it and came over to give some advice to all of the young fledgling dentists.
Our attending took his pointer finger and placed it at the very top of the patient’s head, right where you would wear a hat. Then he said, “push towards my finger as hard as you can as if you were trying to reach it.”
The immediate thought and reaction would be, “why?” To extract an upper molar, we should be trying to pull the tooth towards the lower jaw. That would be in the exact opposite direction of our attending’s pointer finger.
That makes sense doesn’t it? If you push the tooth deeper into the socket, it would only get embedded even further into the jawbone. On the contrary if you pull the tooth towards the lower jaw, you would be pulling the tooth out of the socket.
So, why did he want us to push the tooth into the socket rather than pull it out of it?
The Wedge Principle
The reason for applying apical pressure to a tooth during an extraction is to utilize the wedge principle of exodontia. It is an important but often glossed over technique by rookie dentists in removing teeth.
The wedge principle dictates that two objects cannot occupy the same space at the same time. If you try to insert an instrument such as an elevator or forceps into the apical space of the socket, two things can happen.
- Force the tooth out out of the socket.
- Expanding the bone socket.
Forcing the tooth out with apical pressure
If you try to insert the elevator into the socket, the tooth will begin to get lifted out of the socket. There is only so much space inside the socket. If the elevator is going to occupy that space, the tooth cannot be in there at the same time.
You can think of what is happening that is similar to a bathtub that is filled to the brim with water. As soon as you try to step into the bathtub, the water will overflow since it is so full.
The same exact situation occurs when you insert instruments apically into the socket. It essentially forces the tooth out of the bone.
Alternatively what can also happen if you force the instrument apically is that the bone socket can expand outwards. Instead of the tooth getting forced out, you can actually create a larger and wider socket. If the socket is bigger, it will be easier to remove the tooth since there will be less surface friction holding it in.
An analogy would be trying to pull a fence pole out of the ground. It is pretty difficult to do especially if it is planted very deep into the ground. However you can make it easier by digging away dirt around the fence pole. That should make it easier to remove.
Essentially what happens with wedging an elevator into the socket is similar to removing bone around the tooth. It is the same thing that happens with the fence pole.
Tooth extractions have become a lot more pleasant after I’ve been incorporating the wedging principle. It definitely seems counter intuitive at first but if you understand the logic behind it, it actually makes a lot of sense.
What I keep repeating to myself is that two objects cannot occupy the same space at the same time. If I try to insert the elevator apically, the tooth will get squeezed outwards. What it also does is help expand the bone around the tooth which facilitates its removal.
Last but not least there is one additional reason to apply apical pressure but this is for when you’re using forceps. If you push the tooth apically while holding onto it with forceps, it moves the center of gravity more apically. What this does is decrease the chances of the tooth fracturing while you luxate the tooth buccally and lingually.
Decreasing the likelihood of the tooth breaking during an extraction is a big incentive to utilize apical pressure. As all dentists know, if the tooth breaks in the middle of the procedure, it’s going to take a lot longer to get the tooth out. You usually have to break out the high speed handpiece and start drilling away bone once the tooth breaks. That is the only way to remove the tooth if it is broken.
That just adds a lot more time to the treatment and then you’ll most likely have to prescribe antibiotics (amoxicillin) to the patient. If you’re drilling away bone you’re going to have to do that! In other words, the procedure changes from a routine extraction to a surgical one. It means that treatment just got more complicated.