Distal Preparations


Okay, so now you have your two anterior sites prepped with the two-millimeter twist drills, right? We're not finishing these preparations or placing these implants until we find the posterior sites and find out exactly where our implants are going to go in these distal sites.

So what you want to do is reflect the tissue back until you find the mental foramen. Now, you can use this periosteal elevator. I prefer to use a bigger periosteal elevator just so you reduce the chance of damaging the nerve. But you can just reflect back, just keep reflecting, reflect until you see that. It's not going to be as distinct on the live patient because you're actually going to have something coming out of there. You're not going to see a hole there. You're going to see some tissue coming out of the mandible. And so you'll see it around this area right here, alright?

And so obviously you want to make sure you avoid compressing or damaging any of the stuff that's in here. And so you're going to be placing your implant distally, right? So it's going to be like this, okay? And you got to keep in mind that sometimes in the mental foramen or inside this area right here, there's an anterior loop. So the nerve comes from back here and exits here. But sometimes the nerve does a little curve anterior and then it comes out. So we want to avoid that. The average anterior loop is like two and a half millimeters, something like that. So you do want to look at a cone beam just to make sure what your patient's anterior loop looks like.

But one rule of thumb that I use is to just place my implant so that it's kind of pointed so that I'm aiming it six millimeters anterior to this, alright? So six millimeters anterior to this. You want to measure that out. If you have a period probe, you want to use that. I'm just going to use this right here. So six millimeters, I can kind of eyeball it. And so what you can use, you can use a pencil, you know, a sterilized pencil. You can use a surgical marker. What I'm going to use right now because I've got it and just to make it really easy for you to see is I'm going to mark with this little round burr six millimeters anterior to the foramen.

Alright, so I marked six millimeters anterior. And so now I know that I want to aim my distal implant towards this little marking, alright? And so what I like to do, if it was an extraction and implant placement site, I like to aim by using the extraction sites. So I might say, okay, I'm going to place it kind of through the extraction site of the canine or into the premolar and then it's going to go through the canine extraction site towards the apical portion. But in this case, it's a healed site. So I'm just going to place my implant straight in here and aim it right there.

And I want to be aware of this angle, the angle between these two. So let's go ahead and prepare this implant site right here. I'm going to switch off my drill. Give me just one second. Alright, so now I got my lance pilot drill. And this part is very technique sensitive. You can use a denture guide. You can use a 3D printed guide. I mean, use whatever you want. I'm just telling you what I do and it's working out okay for me. But yeah, I would use a clear denture guide. If you're just getting started, use a clear duplicate denture with a trough, a lingual trough, and then you're better able to approximate these things.

So here's my side view. So I start it here and then I bring it up here just so I kind of confirm the angle. Alright, if I place it like this, that's like a 15 degree angle. I don't want that. I want a 30 degree angle, right? Because you want to get as far distally as you can. So see right there. That looks like approximately a 30 degree angle. I'm going to get started. Remember, I'm getting started and then I'm going to re-evaluate.

So now that I prepped it, I'm going to put this back in and I'm going to re-evaluate my angles. Okay, that looks like, I don't know, it looks like it could be like a 25-degree angle or something. But I think that's looking pretty good. Let's see if we're aimed towards that marking. Yeah, we're aimed towards that marking. If anything, we're just a little bit shy of, we're like a little bit even further from the mental foramen and the nerve than we need to be. But it's always better to play it safe.

Alright, so I'm going to go ahead and keep preparing. I'm going to angle this just a little bit more because our angle is just a little bit conservative. I find that, at least in my situation, I under-prepare the angles. What I mean by that is when I'm aiming for like a 30-degree angle, I do like a 20 or 25-degree angle.

All right, so let's go ahead and reflect it back so you still see your little markings there. And, all right, ready, let's do it. I'm just going to take it a little bit further. All right, so that's looking better to me. So I'm going to take the twist drill now. And what you should probably do at this point is switch these front ones out. Switch these front ones out to paralleling pins because you need these now. You need the twist drills. So I'm going to take this out and put my little parallel pin in there. Okay, and now I'm going to go ahead and prepare this sight right here with a two millimeter twist drill.

Trying to give you the best angle possible. We're trying to give you the best view possible. All right, I'm going to prepare this one for an 11.5 as well. All right, so now you can evaluate the angle again. What do you think about that? Is that like a 30 degree angle? Yeah, all right. So let's move on to prepping the other side. So now I'm going to take my periosteal elevator again. Let me get this out of here. And take my periosteal elevator again. And I want to reflect this tissue back until I find the mental foramen. Reflecting it back. There it is. It's pretty obvious on this model again, but like I said, in a real patient you're going to have stuff coming out of there and it's not going to be obvious.

So the best way to find it is actually do not reflect here, but reflect in front of it and behind it. And then this tissue is going to reflect fine. This tissue is going to reflect fine. And then you're going to find that tissue right here, it stays kind of stuck. And as you reflect more, you'll be able to see distinctly that that tissue is stuck because it's coming out of the mental foramen. All right, and what did we say our rule was? We're placing six millimeters anterior to the mental foramen to try to avoid any anterior loop complications. But again, I'm just going to say it again just because it's so important, look at your cone beam, see what the anterior loop for your patient looks like. An anterior loop might be three millimeters or it might be one millimeter. So six millimeters, placing implant, sorry, pointing the implant six millimeters anterior is a decent rule of thumb, but it doesn't work all the time.

All right, so let's go ahead and mark that six millimeter point. Remember, you should use like a pencil or a surgical marker. I'm just going to show you by marking on the mandible. All right, so let's do six millimeters anterior. All right, so that's six millimeters anterior. And so now I'm going to aim my implant at that site. So in real life, you're using a Minnesota, right? A Minnesota right here. And your assistant can use a periosteal elevator and just kind of retract the lingual tissue just so you can have a better view. But yeah, so I'm using my fingers right now. All right, so remember, if we place it straight up and down, I can aim it here, but we're not going to get any good AP spread. So we're placing it back here and aiming it at 30 degrees towards that little bullseye that we made. All right, so let's go for it.

All right, so now I'm going to take my Lance pilot drill out of the drill, out of the contra angle. I'm going to put it right here so we can evaluate our angle. So we should look at it like that. How does that look to you? Does it look like 30 degrees? Looks pretty close to me. And does it look like we're aimed at that sight? Yep. Staying away from the mental foramen? Yep. All right, so let's keep going. We're going to take our 2mm and we're going to take that one to depth. So our 2mm long is over here. And this one, I'm going to take a 2mm short and put it in here. You might not have a long and a short in your kit, but it's fine. This one, this one actually doesn't need to be in here right now. You can just, you know what? Why don't we just work with one drill? This one doesn't need to be in here because the angle that I care about is comparing this distal implant angle to this anterior implant angle because we know these two are parallel already, right?

So I'm going to put it back into the preparation and I'm looking again from the side, approximating 30 degrees. And let's go ahead and take it to the depth for an 11.5mm implant. All right, so now I have the two distal sites prepared. I'm going to put that in there. The two anterior sites prepared, the two distal sites prepared, and I'm pretty happy with how it looks. What do you think? Yeah? All right, so now what you can do at this step is if you have a cone beam, you can take an intraoperative cone beam. I think that's a good idea, especially if you're just starting to get comfortable with this procedure. Take an intraoperative cone beam just to triple check where you're at and you can triple check how close to the nerve you are in that cone beam. That would be really helpful. You can also take a pano right now. Just have the patient recover a little bit and walk on over to the pano. That's a way to just feel really good about the sites before you move forward. Right now, things are still changeable, but once you go ahead and place the implants, it's a lot harder to change. Make sure you're happy right now. Switch sides at this point to this side. If you're working on the patient's left, switch over to the patient's right and check the implant angulations. Ask your assistants, ask your friends, so you can see that my angles line up pretty good. That's pretty great. I'm happy with it. Anyway, after some imaging, if you have it, then let's go on to the next step.

Lesson Summary

The process of preparing a dental implant involves several steps:

  • Evaluating the angle of the drill
  • Reflecting tissue to find the mental foramen
  • Marking the placement of the implant
  • Aiming the implant at a specific angle
  • Using a lance pilot drill followed by a 2mm drill to prepare the site
  • Emphasizing the importance of parallel implant angles

It is important to use cone beam imaging to check the depth and proximity to the nerve, and to be satisfied with the site before placing the implants. Switching sides and checking the implant angulations is also recommended.

In the case of two anterior implant sites, it is crucial to locate the mental foramen and avoid damage to the nerve. The presence of an anterior loop should be considered when placing implants. Cone beam imaging can help determine the exact location of the nerve and the anterior loop.

When measuring and placing an implant in relation to the mental foramen, tools such as a perioprobe or sterilized pencil can be used. The implant should be aimed six millimeters anterior to the foramen, and the desired angle should be achieved. Cone beam imaging is essential to confirm the patient's anatomy.

Precision and caution are emphasized throughout the implant placement process. Imaging techniques like cone beam scans should be used to triple-check the placement before proceeding. Reflecting the tissue to locate the mental foramen and avoid damaging the nerve is also important.

Overall, the text provides detailed instructions and suggestions for the preparation and placement of dental implants.

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