Основы позиционирования стоматологического микроскопа

So there are three axes of scope positioning to keep in mind. The first is the X-axis, which is side to side, then there's the Y-axis, up and down, and then finally the Z-axis, which is just front to back, and that's it. Those are the main ones to keep in mind. They're important, and we wanna know where the neutral position is in each of these axes, so we can figure out where we're supposed to be most of the time, and then once you get comfortable, you can figure out: "when is it a wise idea to deviate from the neutral position?"

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And there's actually quite a few times. In fact, in the Z-axis, I'm deviating all the time from the neutral position, but it's important to know why. And the reason you do wanna know why is because it allows you to make what I call strategic trades. For example, sometimes for a critical final impression, I will trade ergonomics for a great vantage point and make that trade very happily, as I'll only be in that position for a very short period of time.

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The Y-axis is the first one we're gonna talk about (though I know I mentioned the Z-axis) but let's jump into the Y-axis first. And essentially, it's just your up-and-down axis, and neutral position in the Y-axis is where the oculars come straight out and meet your eyes in a comfortable spot. So this would be neutral, and it offers a really nice blend of light intensity, working space, magnification, and field of view.

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So when you're at the lowest magnification here, [neutral position] gives you a nice reasonable field of view, and it also is very ergonomic, too. So it's a nice place to start, and this is what I would recommend most of the time with the Y-axis.

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Now, the Y-axis will differ with different microscopes in terms of the neutral position. So right now, for the OMS 2050, which I have here, this is neutral position for the microscope, but the OMS 2380 has an angled beam splitter- an upward angled beam splitter. And what happens with the OMS 2380 is that in the neutral position with that scope, [the angled beam splitter] actually forces the scope down for me to have these oculars level [with my eyes].

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And what that ends up doing is it limits the amount of space that you have between the mouth and the objective lens, especially if you add spacers (i.e. ergonomic extenders). Because with each spacer you add to that extension, in order for you to meet the oculars at the same point, you have to move the scope lower and lower and lower.

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So that's one thing I really like about the 2050 microscope, is that the beam splitter is 90 degrees. So even though I've added a spacer here, there's no vertical component to that spacer. It's all horizontal because of this angle here, and that means I have a very, very nice neutral position in this Y-axis. There's lots of space between the objective lens and the patient. So it's a beautiful thing. That's a bit of an aside, but I wanted to talk about it.

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Now, when would you wanna deviate from the neutral position in the Y-axis? Well, sometimes you want a little bit more field of view, and if you think about it, if you move the scope up a little bit, it can give you more field of view. But if you're sitting, you have to start tilting your neck up, and it's not that comfortable.

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So a much more practical way to actually get a little bit more field of view, if you wanna cheat on the field of view thing, is to just stand up, and realistically, I'd move the patient up a little bit, too. But you can actually just have the microscope quite far away from the patient, get a nice field of view, as you can see on the iPhone screen there, and then obviously, I'd tilt the oculars up a little bit, and now I have a really nice field of view.

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This is how you can minimize your lowest magnification (i.e. achieve wider field of view). What is gonna happen, though, when you do this, is the light beam is gonna get broader and dimmer, so you are gonna maybe shine light in the patient's eyes here. Make sure you have good sunglasses for them, and you can also just turn up the light if you need to a little bit, if you feel like you're losing intensity.

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But if you are working on a composite restoration where... the color accuracy is really important, and you wanna maximize your working time, this is a nice way to do it, because by moving the scope further away, you make this light even dimmer. So the lowest setting on the LED gets even dimmer; that's a nice option.

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Now, what's the opposite of moving it up? Well, you can move it down as well. So if I'm sitting and I wanna move the microscope down, I can actually effectively increase my magnification, and this can be helpful.

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Say, you're doing an endo (i.e. root canal). Let me grab a mirror here, actually. Say, you're doing an endo (i.e. root canal) on an upper molar, and it's a retreat, and you broke a file, and you need as much light as possible. Well, say I'm at maximum light intensity. I can just bring the microscope closer, focus with this knob to account for any focus discrepancies, and then when I really zoom in here, you can just see how incredible the magnification actually gets.

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Now, the problem with doing this is that you'll find that there's less space for your assistant to work because you're bringing the objective lens closer to the patient's mouth, and you're also tilting your neck down. But I will tell you that tilting your neck down is not such a bad thing compared to tilting it up. So I just find that a lot of us are used to that anyways, coming from loupes. So tilting your neck down to meet the oculars doesn't really seem to have that much of an impact on ergonomics, so you could definitely get away with it a little bit easier than trying to move the microscope up, turning the oculars down, and looking up like this. Yeah, it's not comfortable, so, uh, keep that in mind.

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Let's talk about the X-axis next. So with the X-axis, neutral is just straight up and down, and then you can either offset it to the right or to the left like that... different microscopes have different mechanisms. The OMS 2050 does this without moving the oculars. Most of the microscopes, the whole thing (including the oculars) will move as you do that.

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90% of the time, you just wanna be in neutral position, where the microscope is up and down (i.e. vertical). But sometimes you do need to tilt the microscope (to the side) to improve your angle. However, you can usually avoid this by just asking your patient to move their head, as we've discussed in the past.

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In any case, if you do need to tilt the scope, you temporarily sacrifice ergonomics, no matter what microscope you're using. So what I mean by that is that some microscopes try to minimize this, and this is one of them, by having the microscope turn without the oculars turning, too.

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So the idea is, is that by having the microscope set up in this position, my head is still straight, my neck is still straight, but you'll notice that if I'm working in this area, my shoulders definitely are offset, and there's probably gonna be a little bit more tension in here than there would be otherwise. It's still better than tilting your whole body like this, but it's not perfect.

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So if you can stay in the neutral position, you're better off, but it's nice to have an option to be able to move the scope without really doing too much to your ergonomics, and that's where the OMS 2050 really comes in handy.

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Now, there's also other accessories for the other scopes that help you achieve the same thing, but it's just not automatic. So with the OMS 2050, it happens automatically as you move the microscope. With most other microscopes, there'll be a little ring here, a rotation ring, and you'll have to actually turn the oculars once you turn the microscope.

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So what would happen is, you turn the microscope, the oculars would turn with it, and you have to turn them back this way to balance them out. It's an option, right? But I have found that I've never actually used it on any of the microscopes that have had that feature, and I've had two other microscopes that do. I just don't use it. I just find it's one extra thing to do, and yeah. So when it's built in, it's amazing how much more usable it does become.

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Now, finally, let's talk about the Z-axis. So this one will be the one that you see the most talked about in the course, because it's very, very important for positioning, and essentially, there's three main positions to keep in mind. I'm gonna turn the microscope a bit so you can see it better.

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So neutral is when the microscope is essentially straight up and down like this. Obtuse is when the microscope is pointing away from you, and usually the oculars, you have to bring them up a bit; so you can see that there's more of this obtuse angle going on. And then the other one is acute, so like this. The microscope is tilted back at you, and then you bring the oculars down a little bit to meet them.

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So there's different reasons you'd use these different positions. For the upper arch, neutral is usually best. You can get away with obtuse as well, (when using indirect vision). It just depends on what you're doing, but I find that neutral is typically the best for the upper arch, because you prevent yourself from getting in your own way.

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So if I have a neutral scope position, and I'm looking at these upper molars, I can very easily get in here, do my work, and I'm just not getting in the way. I'm very comfortable. Oculars are meeting my eyes.

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But if you don't have a spacer (i.e. ergonomic extender) like I do, sometimes you'll catch yourself, like, leaning forward a little bit to meet the oculars, and in that case, what you can do is just opt for a slightly more obtuse angle here, where you move the microscope a little bit like this. Now you have that obtuse position, and right now, these oculars are too close to my eyes because I have the spacer. But you can use this obtuse position if you wanna be further away from the patient.

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The problem is that a lot of times, if you're working in the obtuse position, and then you're trying to do a crown prep on the lingual of tooth 2-6 (i.e. this first molar on the left) you bring your handpiece in, and the handpiece will block your view. Kinda looks like this. I don't have a handpiece on hand right now, but the idea is that... Actually, I'll stitch some footage over here from one of the live patient demos....

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Now, this is a common problem with obtuse scope positioning, is your handpiece will get in the way on the lingual. So to overcome this, you wanna be able to see over it, so I need to move my microscope further away from me, so I can see over this. So I'm gonna do that. And now, when I'm looking at the lingual, I can see over my handpiece. I got this little window to work, right? Now, big stretch open there for a second, Jeff. Good deal.

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You'll see how the handpiece just gets in the way of what you're trying to accomplish, and it's a pain, and I find that the neutral scope position overcomes that. It allows you to see over the handpiece.

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So I prefer neutral scope position for the upper arch when you're working with indirect vision. Get a spacer if you need it. I'd say thirty-five millimeters is a good spacer for most people. You also can opt for a fifty millimeter, like I have. Just means you have to make things a little bit more tense on the knobs to balance everything- that's a bit of an aside here.

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What about acute positioning? Actually, before we move on, I wanna mention one other thing about obtuse positioning, is that it's very good for direct vision on the lower arch. So if I wanna look at the lower teeth directly, I would do that with an obtuse microscope position. This just gives me a beautiful view of those lower molars.

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Now, how could I improve this even more? Well, I could actually lift my patient up, and then they will be situated in a way that allows me to almost have a top-down view of these molars. So I'll actually do that. I take my patient, lift them up a little bit, drop them down a bit more.... and then I go back into that same obtuse position- you can see just how nice of a direct view I have.

So keep that in mind: with a semi-supine patient and a obtuse microscope position, you get a really good direct view. I use it all the time for exams- not so much for restorative in the lower arch, but I'll use it all the time for exams where I'm just doing a check of the lower vestibules, and I'll use this obtuse scope position. So that's a nice option.

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I'm gonna move him back down to a semi-supine- sorry- a supine position. And now let's move to the acute microscope position.

So for the acute position, what we're doing here is moving the microscope away from us and then tilting it back towards us. And by doing that, we can get a really nice view of upper arch direct vision, say, for anesthesia. So, so for example, if I wanna freeze up in the upper vestibule here, we've got a really nice view, right? [the acute position also allows us nice] indirect vision of the lower arch.

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Now, this is something that a lot of people aren't really used to in the sense that you normally don't have that great of a perspective with loupes to use indirect vision on the lower arch. But with the microscope, your perspective now has the ability to start here instead of at your eyes. So instead of my perspective starting here and seeing from this angle, I'm seeing from this angle, and that's much, much more favorable for indirect vision on the lower.

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And that just makes things way easier in terms of being able to move the mirror. You can see exactly what you need to. You can see straight down the tooth when you're doing endo or prepping proximal boxes, and it's a beautiful, beautiful thing.

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What I will tell you, though, is that the, the scope position in the acute Z-axis is harder to reach ergonomically. So what'll happen is: say, you don't have a spacer (i.e ergonomic extender) here, you'll have to actually lean quite far to reach the oculars, and it can put a little bit of strain on your lower back. And that's why I'm such a fan of these extenders...

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Yeah, I have to lean forward a little bit, but I'm very comfortable, and I can get a beautiful view. Look how far my mirror is away from these teeth as well; there's gonna be way less water splatter because I've got this acute angle going on.

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It's hard to simulate on a mannequin, but when you're working on a real patient, if you try to use your mirror at an obtuse angle or a neutral angle, it becomes very challenging to get that mirror far enough away from the patient's tooth such that it doesn't get splatter all over it. And especially when the patient has a little bit of a limited opening, it's very hard to get the angle of what you need to see.

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So those are really the reasons why I'm a strong advocate of the neutral or the acute scope position when you're doing indirect vision on the lower arch. You'll also see me use it quite often for impressions on the upper arch.

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And to give an example of that- if I wanna take an impression of this molar here up on the top left, I like to be able to see the buccal and the lingual of this tooth, and I'll just position the microscope like so, and I can very, very easily do my impression here, and it's all direct vision. I know that I'm capturing the entire, the entire prep as I do that.

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So I tend to use acute just as much as I use neutral- obtuse position I use a little bit less because I'm not doing as much direct vision, but for exams, it's invaluable.

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So with the Z-axis, be prepared to learn all three positions, and the Z axis, I would say, is the most important of all the three axes.