[Surgery]  All-on-4 Surgery - Initial Implant Stability and implant lengths

Hi guys


Hope all is well with you!  


I have a question regarding All-on-4 surgeries and initial implant stability.   I have been doing some All-on-4 cases over the past 6 months, trying to keep the cases straight forward and simple at this point.  What an amazing treatment treatment option for our patients, really unbelievable!


I have a more challenging case that the patient wants to go ahead with, my concern is bone quality and bone volume.  I exo'd the remaining Maxillary teeth about 8 months ago and grafted the site (used a particulate graft, was before my PRF training), there was a significant defect in the 22/23 area due to advanced perio.  You looked at her original CT for me and recommended grafting first as opposed to the immediate all-on-4 at time of extraction due the huge void in this area.  


Looking forward, it appears from the CT scan that my maximum implant lengths (I usually use Speedy) for the procedure would be an 4.0 X 13.0 for the #15 (tilted), a 5.0 X 11.5 for #25 (tiilted), and the anteriors would be 4.0 X 8.5.


So I have three questions for you, the experts!


1)  Do you feel these implant lengths are sufficient for an all-on-4?  Her Mandible is restored with an All-on-4, just so you know opposing occlusion.   I am thinking that perhaps a third anterior implant would be a good idea?



2)  If I decide to place three anterior implants (All-on-5 instead?) would the third implant go right in the midline?  I have never placed an implant directily in the midline, what do I have to do to be cautious of the nasopalatine/incisive canal?  On the CT there is sufficient bone anterior to the canal, do I just be cautious of not entering the canal?  Do you get overly concerned with the nasopalatine nerve and vessels when working around them, wether reducing bone or placing a midline implant?


3) The guidelines are not to load an All-on-4 case without initial insertion torque of 35 N/cm, I am concerned about the large grafted area, although it appears to have healed well on the CT....    I have heard you and others mention gaining stability by 'biting' into the cortical plate of the floor of the nose.  I have not tried this to date, my understanding is that you take the 2.4 drill into the plate slightly, and allow the tip of the Speedy to engage the plate?  My question is what is what if you perforate the plate, which obviously isn't what you try to do but as with any surgery you have to be prepared for the possibility....  Would you still place the implant?  Would you be able to give me some insight into this approach of entering the cortical plate and how technique sensitive it is?   The last thing I want to do is get in over my head attempting something like this.... I routinely drill up to the floor of the nose and can feel when I'm there, but have never required to 'bite' into it for stability.  Do you estimate off the CT the thickness of the plate?



Thanks so much!  As always it is very much appreciated!




by Sean Bicknell at Thu, Feb 9, 2012 3:03 AM

1860 Views | 2 Replies


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Mark Kwon Replied at Mon, Feb 27, 2012 10:45 PM

Hi Sean, My apologies. I confused myself thinking that i have already emailed you the replies. My mistake. 1. Whenever, im forced to use shorter implnts, especialky in the upper jaw, i like to put more implnts, Allon5 or Allon6. Yes, i agree w your decision. 2. I like to avoid incisive canal, not because i worry abiut entering the canal, but more likely i eont get stability and will not get integration. Often the positions are : 5,3,1,3,5. Or 5,3,1,1,3,5 3. "grabbing the nose technique" - something i need to do often in extreme cases; very technque sensitive. Be careful! The idea is to perforate the floor without perforating the nasal membrane. Remember, nasal cavity is full of bacteria! You need to exactly drill to just shy of 2.4mm not more, or else, you will lose engagement often times. Hope this helps, - mark

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Mark Kwon Replied at Wed, Feb 15, 2012 6:28 PM

I believe that i've answered these questions. thx.