Likes : 0
Bernard Jin Replied at Thu, Feb 24, 2011 2:45 AM
Hi Sean In this case, my under prep would apply to both the depth and width of the osteotomy. Undersizing the osteotomy width-wise would aide in achieving better stability. Undersizing the osteotomy depth wise would help avoid an unintentional sinus perforation. Note: the word unintentional. In the SA-2 approach, my goal is to stop short of the sinus floor. My rationale for undersizing the osteotomy depth wise actually has to do with the 'up-fracture' of the sinus floor (whether with an osteotome, implant or other apparatus); it provides me with a 'buffer zone' with which I can safely compress and expand the bone. I have seen several methods of performing the SA-2 sinus lift - and it depends on operator preference. I don't think there's any one method that is superior. If you are already placing Nobel Active implants, you would develop the 'feel' of bone compression upon placement. This 'feel' comes in handy when performing an SA-2 using the implant only. In cases such as these, I also place a membrane (bovine type IV collagen membrane or PRF) prior to performing the upfracture with the implant. That way - with the upfracture, I feel more confident that the implant has not completely penetrated beyond the Schneiderian Membrane because the membrane I introduced acts as an additional barrier. If/when I see/feel the schneiderian membrane through the socket.... My reaction/decision largely depends on the amount of bone around the schneiderian memb. exposure (and the size of the exposure, whether the memb. is torn or not, etc.) Assuming a small exposure, no tear, and still significant bone height present, I might approach the way I described above. If the bone is minimal, then I would approach it as a possible SA-4 - such as close the exposure with a membrane and/or laterally rotated gingival flap. I would then possibly revisit the sinus another day (weeks later) to perform a lateral window approach. I realize I didn't fully answer your question - especially to the detail I think you are asking. But there are many 'avenues' we can take - depending on the situation. I hope that helps answer a few of your questions, though. Regards, Bernard
Likes : 0
Sean Bicknell Replied at Wed, Feb 16, 2011 7:01 PM
Thanks for the info! Bernard, one quick question. When you say undersize the osteotomy do you mean depth wise or width wise? Or both. I know I've undersized osteotomies width-wise in soft bone situations. In this circumstance above I believe you mean to underprep depth-wise to allow the sinus floor to be "pushed' apically by the implant and remaining bone, as per an SA-2 apporoach with an osteotome? You would do this without an osteotome? Can you walk me thorugh your technique? If the sinus floor is at the apex of the tooth (i.e you can see/feel the membrane through the socket), how do you treat? Thanks Sean
Likes : 0
Mark Kwon Replied at Sun, Jan 30, 2011 4:26 AM
I do agree with dr. Jin. I would recommend CT scan. Find out location of the roots. Whatever you do avoid buccal perforation. Stay palatal. If palatal socket exist, you are safer there than in buccal socket.
Likes : 0
Bernard Jin Replied at Fri, Jan 28, 2011 3:17 AM
Hi Sean, Thanks for your post & encouragement for the forum. Regarding the exo of 25, if left unattended (i.e. no ridge preservation), the bone will likely resorb significantly. Especially if left for months, the resorption of the alveolus will occur, in addition to pneumatization of the sinus. Not recommended if you want to place an implant in the near future. I would approach it with one of two options - both of which you had already brought up: - exo & perform ridge preservation with either an allograft or autograft; or - exo and perform immediate implant placement. I would be more inclined to perform the latter (exo + immediate implant placement). And yes - if I did choose this route, I would prefer to use an nobel active implant where possible (for the same reasons you brought up - bone compression & engagement). Since our treatment site is the posterior, I would certainly recommend undersizing your osteotomy (with or without SA-2 approach) prior to implant placement. 2 Reasons for this: the apical portion is deficient in bone volume; and the fact that you are in the posterior maxilla (typically d3 bone or softer). You may have to 'jiggy-jack' the implant a few times to get it to the proper level esp. if you under prep the osteotomy site. In my experience, if a nobel active implant is used, you needn't use an osteotome; the implant takes care of that. I would also try to fill the socket up with as much of the implant as possible (i.e. err on larger diameter than being too narrow). Lastly, if the implant does not give you primary stability, you can always do it as a 2-stage approach. On the other hand - if you do get primary stability - then all is well! Hope that helps, Sean! Good case! Keep us posted on its progress! Cheers, Bernard Jin One more thing: if you look closely - you'll notice that the root is bifurcated. For implant placement, the inter-radicular septum can often deflect your osteotomy drills. Recommend: Precision Drill (avail. from nobel) prior to pilot drill. Cheers!