If your patient is complaining that they cannot fully occlude their back teeth together on one or both sides, there could be a few different factors causing that symptom. Dentists in our clinic will sometimes order a CBCT or MRI scan in order to assess joint integrity, disc placement, and to discern whether there are some bony changes that could be causing the malocclusion. If pain is present, then we usually suspect either joint inflammation or muscle tension or a lateral pterygoid muscle spasm. And those are the two conditions that I most commonly treat in the clinic related to a posterior open bite with pain. When patients are wearing a mandibular advancement device, this is actually one of their complaints in the morning. And when they take that device out, if their muscles are tight, they may have a hard time using that morning repositioner to get back to the right position, and they may find they can't get their teeth together. So if my patient is complaining that she cannot fully touch her back teeth together, in this case we're going to say it is on the left side, I'm going to start by determining is this a joint or a muscle concern. So I will palpate right over her joint, finding that spot in front of the ear. All right, any pain there? A little bit of pain. Is that your familiar pain? Okay, so that's starting to make me think, all right, we've got something that's affecting the joint. For the muscle palpation, I'm going to save that until I'm going inside her jaw. So next I'll look at her range of motion in lateral trusion and protrusion, because the lateral pterygoid is active in both of those motions. So I will get my ruler. Okay, can you show me your teeth? Okay, good. I'm going to line up with her midline of her upper teeth. Drop your jaw slightly open, please, and then move to one side. Okay, she's moving just fine to the left, ten full millimeters back to the middle. And then when she moves to the right, it's maybe not moving quite as far. Maybe it's only five millimeters. And that tells me the lateral pterygoid is not moving as well as it should. Same assessment with protrusion. So start with your teeth together, please. Good, and then bring your jaw forward toward me. Okay, oh, it's not moving too far. It's only about three millimeters, and I see it swinging to the left-hand side. Can you relax? Any pain with that? No. No? Okay. So then I'm thinking, all right, she's not protruding equally with those condyles. Next I will move to my static and dynamic testing. So for the static testing here, what's most important for us to assess is the side-to-side lateral trusion and the protrusion. So I'm going to have you move your jaw. I'm going to start away from this side toward my fingertips over here on the right side. Good, and then don't let me move you. Any discomfort or pain there? A little bit. Okay, is that any of that familiar pain? Yep, so familiar pain. It's the left lateral pterygoid that moves off to the right-hand side. Now I'm going to do resisted static protrusion. Bring your chin forward toward me, okay, and as I'm resisting protrusion for my five seconds, any discomfort or pain there? No. Okay, not too bad. You know, sometimes they might have joint pain, sometimes not. For the dynamic testing, now I'm going to ask her to move to that same side, away from the joint in question, into my finger, one, and then back to the middle, and again two, back to the middle, and three. And if she's having a little bit of a hard time coordinating, I'm suspicious that the muscle's not working properly. And then finally, forward three times into my finger, one, and back, two, and back, three, and back. And sometimes adding a cue, she moves straighter, which makes me think that the muscle is involved. So after going through all this for her, I'm thinking, all right, she's got some joint pain. I'm seeing some signs that her movement is limited. Now I'm going to do some intraoral testing. And so for this, I am going to use a different glove, since I'm going inside her jaw. I'm going to stabilize with the pillow, okay, and then I'm going to be feeling right over her joint, so I can tell how well it's moving. Okay, now for this, I'm going to have my thumb on your lower teeth. I'm going to be wiggling up and down. You raise your hand if it's painful or uncomfortable. And I'm trying to assess for how well the joint itself moves. So go ahead and open just a little here. Good. Keep your jaw as loose and floppy as you can. Take in a breath for me. Nice big exhale, and I'm just going to wiggle up and down. And I'm finding that her joint is bouncing up and down just fine. Good. All right, the next test is I'm going to see if it lets me pull you slightly forward toward me. So now I move my hand up here to stabilize her head. Good. Nice and floppy and relaxed. Take in a breath for me. Nice big exhale. And as she's coming forward, it's just gliding just fine. So I am not suspicious of her capsule limiting her. The disc isn't really in the way. So now I do think it's a muscle problem, not a joint problem. That lateral pterygoid muscle, when it goes into spasm, it will affect how she can move her jaw, and it can prevent us from fully touching our teeth together. Sometimes when I'm doing that movement, the muscle fights back, and it feels like it doesn't let me go, but I can still move it compared to a joint restriction. So this is how I start to differentiate between some of those pieces. The last intraoral part is palpating as close to the lateral pterygoid as we can get. I use my thumb for this, and I'm going to be going up on the outside of her teeth as close to the ear as I can get. So you raise your hand and let me know if this is too painful. Okay, go ahead and open your jaw slightly. Good. I'm going on the outside of her teeth, running back up until I can't go any further. This is getting close to that lateral pterygoid area. Yep, and uncomfortable. When people are in spasm, I feel like I stop almost instantly because there's so much tension in there. The muscle, the masseter muscle, can get in the way, but when the lateral pterygoid's in spasm, that muscle is also tight and activated. So I have determined that this patient has a left lateral pterygoid spasm, and that is interfering with her ability to fully occlude her teeth. This was perhaps triggered by mandibular advancement device use because her pterygoid was tired of being pulled forward all night long. Because it is a muscle spasm, we have some really great ways that we can treat it. Our treatment strategy will be determined specific to each patient. One of the first things we do is to use some ice intraorally. Ice is great at stopping a muscle spasm, but the lateral pterygoid is too deep for us to be able to get at it just using ice on the outside. So at our clinic, we have these little test tubes that we fill with water, and we freeze. And so I will give them to the patient to take home so that they can freeze it and reuse it. I'm going to remind you where you want to put the ice. So go ahead and open your jaw slightly, so outside of your teeth, up as close to your ear as you can. You do not need to torture yourself. So go ahead and take that ice, okay? And then you can put it inside your jaw on the outside of the teeth. Yep, like you're just trying to angle it up inside your ear. Angle it down just slightly, like you're bringing it this way. There you go, going up as high as you can. You don't have to push, but can you feel how that's icing those muscles in there? If it's cold on your teeth, if it's numb, you can take breaks. Take it out, give yourself a few seconds, go back in. It doesn't take very long before it starts to get numb. This is the closest we can get to icing the lateral pterygoid. The patient can take this home. They can use it two, three times a day, and it's a really great way to get that muscle to relax, which will help them to get their teeth back together. So I will encourage people to do this as many times as they need to. Of course, they'll have to refreeze it. People can also freeze water in a rubber glove, tie off the wrist, break off those fingers. You can use the flower tubes once they've been cleaned or sanitized if they don't have access to test tubes. The other ways that we can get a muscle spasm to decrease are using range of motion exercises. These range of motion exercises can also help decrease any muscle inflammation or muscle tension. We can use trigger point release, and then we can retrain movement. So first, I'm going to teach you how to retrain your movement so that muscle doesn't keep overworking for you. And to do this, I will have you put your fingertips right up in front of your ear on that side. Yep. And then I'm going to have you put your other hand on your chin. Yep. Your tongue goes up on the roof of the mouth. As you open, you'll only open as far as your tongue allows. Imagine. Yes. Beautiful. Your hand is just guiding it down and back, and then let it float back closed. You should feel no forward movement clicking or popping under your finger. Then again, drop it down and back. Beautiful. And close about three, four, five times. Good. This is just like if you have a sprained wrist, you pump your wrist. Pumping the jaw works any joint inflammation out of there. So if I had determined, you can put your hands down, if I had determined that she had inflammation preventing her from getting her teeth together, we're going to definitely jump right in with that intraoral ice as well. And I'm going to have her do this pumping motion with her jaw every hour throughout the day to decrease inflammation. This also decreases our muscle tension in the lateral pterygoid and the masseter. So it's a great exercise all around. Five or six repetitions. Try for every hour as much as you can. It should not hurt or cause any pain, noise, discomfort, any of those things. My other manual interventions are either trigger point release. So that's going in where I was before with my thumb, kneading and massaging those muscles. I'll demonstrate it one more time. So go ahead and open your jaw and then you can let your jaw relax just a little bit and close slightly. There you go. And you can teach people to do this on their own at home with clean hands in the shower. You do not need to torture yourself. There is no point in making it hurt because that will trigger the muscles to clench. Good. And there's no magic amount for the massage until those muscles feel soft. I can do some joint oscillations. So going back to my stabilized position, I'm just going to wiggle your jaw slightly up and down. Imagine putty, marshmallows, whatever relaxing image you've got. Okay, good. And then you just breathe normally. And so with this, I might oscillate a little bit. This opens up the joint, makes some room if there's inflammation. I'm not mobilizing her because her joints not tight, but there's a little bit of oscillation will help to decrease the muscle spasm as well as open up the joint space if there's any inflammation. And then finally, the last activity that I like to have people do is to retrain their side to side movements and their forward movements so that they're not shifting to the side. And this is easily done with a clean pinky. So go ahead and just lightly rest that between your teeth. Yep. Good. And then I want you to slowly roll your lower jaw side to side on your finger. Yep. And you can keep those teeth contacting it. Beautiful. That gives the body some awareness of where you are in space, provides a little stretching as well as retraining. Good. You can take your finger out and then we can use a mirror for the protrusion motion. If she's shifting off to the side, go ahead and bring your jaw forward and back. So if she does that in front of a mirror, she'll be able to see if it's straight and she can correct it if it's not.

occlusion

CBCT scan

muscle tension

muscle spasm

treatment options