I think that reliable results could be reached .. The problem that might affect the success of the implant is the perforation that could occur during the process.  However, management of this problem is possible. 

Read the attached article .. It would be helpful tool to understand your concern. 

Best regards

Article Comparison of two different maxillary sinus lifting techniqu...

Thanks for your answer.

It can be very predictable if the implant has been stabilized in the sinus.  Usually this is a function of the type or quantity of osseous structure present.

It depends on the amount of primary bone (not bone graft)in which u have placed the implant.Minimum 3 to 4 mm primary bone with additional graft should give you a torque of about 30ncm with correct implant placement technique

Thank you.

The answer to this question is dependent upon a number of different factors.

Indeed the amount of residual bone through which an implant is placed will determine the initial stability of that implant. Today we know that Implants as short as 4 mm can be used with predictable results.

The question that one should ask is "how do we determine predictable?" By this I mean that using a vague term like "predictable" does not tell you how often something will or will not occur. Something can be predictable at a success rate of 10% or something can be predictable at a success rate of 100%. Obviously you would prefer predictability on the high-end of the success rate curve so when an answer is given, that answer has to be  quantified as well as qualified.

The preliminary studies on 4 mm length implants suggest that osseointegration can be achieved with those implants at a rate that is very similar to that of more traditional length implants. If we put the number of 95% achievement of osseointegration onto the 4 mm implant and the 10 mm implant we now have a meaningful number not just a predictable number. Are you willing to accept a 5% failure rate? Well if that 5% failure rate is the same for implants that are as small as 4 mm in length or as long as 18 mm in length with no variation between the shortest and the longest the conclusion would likely be that there is no difference in the  failure rate relative to length of the implant. But then one must ask when that 5% failure rate is calculated? Is it 5% failure at year zero, year one… Year 20? If we accept the notion that some implants will lose bone height during the initial integration phases and  if we are looking at implants that are only 4 mm in height 1 mm of remodeling bone loss could then be considered to be problematic for the 4 mm implant but may be irrelevant for the six or eight or 10 mm length implant if that remodeling bone loss is the only bone loss that will be seen over the next decade. But if we see progressive bone loss, even if it is a small amount of bone loss on an annualized basis that would certainly be more concerning for a short implant, 4 mm let's say, that it would be for an intermediate length implant of 8 mm or more.

So here I am talking about implant length when the question is about sinus lift. How did I get off topic? Will the answer is that if a 4 mm implant works, works predictably over time, does not lose bone over time, then the sinus lift on an 8 mm implant will certainly also work (assuming that there is 4 mm of residual bone through which the implant passes) because the lift will do nothing but add additional bone if it succeeds and if it fails the original 4 mm of bone that held the implant in place may well be sufficient to maintain that implant. So now the question is whether or not sinus lift gains more bone and that question is only important if additional bone improves the prognosis.

The next question becomes how often does grafting in the sinus improve the bone status of the implant that is placed? We all understand that it won't be 100% of the time. What if the grafting in the sinus improves the situation only 50% of the time? Does that mean that 50% of our sinus lift procedures with grafting will fail? No it doesn't, we're back to the same discussion of the minimum length of the implant that is necessary to sustain function indefinitely into the future.

We know that we can place implants into the sinus simply by elevating the sinus membrane and not placing any  graft but letting the blood clot reorganize, as it will if it is placed under the endosteum, into a fibrin clot followed by  inflammatory cells that will enter the area with neovascularization  formation of bone forming cells that will eventually lead to new bone formation. Does the addition of grafting material improve the situation? This seems to be a question that is somewhat controversial  And the pendulum is swinging further further to the side of the discussion that suggests that the graft itself is not nearly as important as we once thought it was.

What about loading protocols? When can you load this implant immediately?

I think the more important question is why would you want to immediately load any implant that has a small amount of natural, native bone engagement. It's not an issue of cosmetics  (in the posterior maxilla) and more often than not it's not an issue of function because the patient has probably experienced a functional deficit with either the tooth that is missing or the tooth that needed to be extracted in that area otherwise you would not have extracted the tooth. So if there's not a cosmetic issue and there's not a functional issue then why would you want to immediately load a posterior tooth and the maxilla?

If the posterior tooth and the maxilla is part of a multi-implant retained fixed immediate provisional restoration then the connection of that implant to the rest of the fixed prosthesis may well reduce micro-movement on that implant and thereby improve the prognosis of that implant. Conversely if you are looking at a single implant that engages a minimal amount of bone, let's say 4 mm with the provisional restoration that is 2 to 3 times longer than the implant in the residual bone this situation will result in a condition that is likely to have micro-motion and that micro motion is likely to be above the threshold that will prevent the implant from  gaining secondary stability which we could think of is biologic stability.

So considering loading protocols there has to be a very good reason for loading a posterior maxillary implant immediately. With the exception of the multiple implant supported fixed dental prosthesis we can go out on the limb and say that the prognosis is almost always compromised when you immediately load a posterior maxillary implant and the less bone that you have on that implant, the higher the crown to implant ratio becomes, the higher the risk of micro motion, the higher the risk of implant failure.

These sort of questions are intriguing. At the same time they are questions that cannot be answered in a very simple or concise way.

The biology of bone regeneration under der (intact !!!) sinus-membrane is well known:

http://www.hindawi.com/journals/ijd/2012/576238/

(further investigations: just google for "Sennerby", "Kahnberg" et al. (sinuslift + implant placement without graft, experimental studies, clinical studies)

In everyday praxis the most important issue is on the other hand: the INDIVIDUAL prognosis for the treated patient. We want to KNOW how the state of bone regeneration is on an individual basis. Thus a 2-stage-approach seems to be favourable because at implant-insertion in the augmented site by judging the drill-torque-value and the consistence of bone/graft-compound removed by the drill You will KNOW the individual "maturity" of the regenerate  (which will widely differ between young and old, sporty and "couch-potatoes", Vitamin-D-status, nutrition = McDonalds vs. Vegetarian vs. mixed healthy food).

http://www.nature.com/articles/srep05877

To judge the individual prognosis for each patient (which is our duty as doctors) a two-stage-approach seems mandatory (see reference list in article). If You want to rely on statistics, this might be nice for success-statistics of the doctor but always keep in mind: when YOU insert 100 implants and loose 5, Your success-rate is 95%. For a patient receiving ONE implant in a molar-site with sinuslift and losing it, the failure-rate is 100% ...............................

Well said, Agreed with you Dr. Angelo Troedhan.

 Two stage surgery is always better in the cases of sinus lifting followed by bone grafting.

 I forgot: Thanks to Prof. Eckert for his brilliant considerations in practical implantology...... I apologize in advance that I will cite his considerations in one of my next publications .............  :-)

The prognosis of implants placed simultaneously with sinus augmentation is well established and documented.You can go to our first publications in 1998-1999 and later on 2006 in JOMI showing data of 731 sinuses with more than 2000 implants placed simultaneously regardless of the residual bone height ..It was shown again by Testori and Del Fabro in their publications.The only factor is achieving primary implant stability. 

Thanks Dr. Ziv Mazor, Will go through your documentation.

The unique important factor to achieve implant osseointegration simultaneous with sinus lift  is primary stability. If you add some autologous bone taken ie with a scraper from the sinus window, you can reduce the time for loading

 Agreed with you Dr. Luis But in such cases there wont be much of compact bone at the apex of the implant immediately place after sinus lift. It will be surrounded with fresh bone graft only.

The prognosis of implants placed simultaneously with a direct lateral window approach to the sinus lift bone graft is dependent on pre-surgical assessment with CBCT, precise execution of the sinus lift with an intact membrane avoiding over dissection and encroachment on the lateral nasal wall. The lateral sinus window should be located at least 5-7 mm above the sinus floor facilitating the condensation of the graft in the area of implant placements covering the apical portion of the implants. Use of a composite graft consisting of a bone graft substitute( Bio-Oss) in combination with autogenous trabecular bone or the bone graft substitute alone is documented to have the highest success in the literature. The graft should be contained within the lateral window as excess graft material can result in complications such as superficial graft infection. Use of PRP twill improve the handling of the graft and stabilize the graft inside the sinus cavity. A non-cross linked membrane is recommended to cover the grafted window. Use of blood component therapy such as L-PRF can be used as a substitute for a collagen membrane for stabilization and containment of the graft and will contribute to an improved soft tissue cover. Within 4 months, the graft will be matured enough to support implants loading. Long term success depends on a protected group function occlusion. I have been performing the above described procedure since 1989 with up to 27 year follow up of stable cases. I wish you success using the protocol described here in.