TRANSCRIPT:

In this scenario, we only have 4 millimeters of bone height available from the alveolar crest to the sinus floor. In this situation, I myself would not do an indirect sinus lift and it's not something I would recommend without extensive experience and confidence in what you can consistently achieve because literature shows us that it is difficult to achieve a consistent bone growth of more than 3 to 4 millimeters, and predictably we can do about 2 to 3 millimeters.

For me, placing an 8 millimeter implant, I want to illustrate why doing an indirect sinus lift with 4 millimeters of bone would be difficult for me. Let's plan our osteotomy here. I'm going to drill that osteotomy and take it to 1 millimeter shy of the sinus floor, so we've got 1 millimeter here, and I'm going to do a 5-millimeter width. Now this osteotomy is only 3 millimeters in depth.

Then I'm going to take my 5-millimeter osteotome, sometimes they're slightly undersized, like 4.8, whatever your kit is, but you're going to want to use that osteotome. We're going to place it apically. I like to do just a gentle tap here with my osteotome, keeping a finger rest on the osteotome, keeping a finger rest on the tooth to prevent displacement of the osteotome into unwanted territory.

I'm going to gently tap apically and I'm going to actually up fracture and displace this sinus floor bone, which is 1 millimeter in height, and I'm going to get that about 2 millimeters up. So I've gained an additional 2 millimeters here and 1 millimeter in bone. Now I know that from this crest I actually have, from here to here is 4 millimeters, I've gained 2 millimeters that I'll pack with bone, and I have 1 millimeter of bone height.

So I actually have a total of 7 millimeters of bone availability, which is great, however, my implant is 8 millimeters. Now when I place my implant, it's going to actually go through that graft by an entire millimeter, and actually if this hard piece of bone is intact, it may even push, the apex of the implant may even push that harder bone stop up into the sinus and create a perforation, or the implant itself could create a perforation.

If none of those things happen, this implant will, in a best-case scenario, have a millimeter of exposure that is not covered in bone. Again, does that mean that that implant can absolutely not heal? Not necessarily, however, I'm starting off at a disadvantage with an implant that doesn't have apical bony coverage, doesn't have a bony stop, has a higher risk of implant failure, and I've created a situation where I have a higher risk of perforation, whether via the apex of the implant or via dislodgement of that bony stop apically through the membrane.

This illustrates why even though it might seem like, well it's only another millimeter, maybe I can just do an indirect lift anyway, that extra millimeter or two can really create a difference in the ability to effectively elevate the membrane without perforation and place an implant that has adequate bone at the apex and bony coverage. Keep that in mind when you're planning an indirect versus a direct implant placement.

I will say again that there are practitioners with many, many years of experience and many, many sinus lifts under their belt that can get more than 2-3 millimeters, but doing so predictably is difficult and takes a lot, a lot of experience. So this kind of number here, this 2-3 millimeters, is something that I think all of us, and I still do myself, is what I shoot for and what I know I can predictably get with an indirect sinus lift.

Lesson Summary

In this scenario, there is only 4 millimeters of bone height available from the alveolar crest to the sinus floor. However, it is difficult to achieve consistent bone growth of more than 3 to 4 millimeters with an indirect sinus lift. Placing an 8 millimeter implant with only 4 millimeters of bone would be difficult and risky.

Reasons why an indirect sinus lift with 4 millimeters of bone would be difficult:

• The osteotomy would only be 3 millimeters in depth.
• Fracturing and displacing the sinus floor bone would gain an additional 2 millimeters, but still leave only 1 millimeter of bone height.
• Even with a total of 7 millimeters of bone availability, the implant would still go through the graft by 1 millimeter.
• This could result in the implant pushing the remaining hard bone up into the sinus, causing a perforation.
• In best-case scenario, the implant would have a millimeter of exposure not covered in bone, which increases the risk of implant failure.

In conclusion, an extra millimeter or two can make a significant difference in the success and predictability of an indirect sinus lift. It is important to carefully consider the available bone height when planning an indirect versus a direct implant placement.

Note: While some experienced practitioners may be able to achieve more than 2-3 millimeters of bone growth with a sinus lift, it requires a lot of skill and experience. Therefore, aiming for a consistent bone growth of 2-3 millimeters is recommended.