From: Tommie Van de Velde
Sent: Friday, January 05, 2007 4:30 PM
To: implants@rximplants.com
Subject: [implants] perforating mini implants
Hi everyone, this is my first case that I post on this newsgroup. I got this addicting forum from a collegue endodontist.
Congratulations for this initiative!
The case is a medically compromised 74 year old lady who had problems with her lower denture. She didn't? want to undergo
general anaesthesia for a bone augmentation procedure. She visited several implantologists who didn't want to proceed with
regular implant therapy being scared of fracture of the lower jaw.
I decided to go for those mini-implants (Imtec) to allow a maximal bone conservation around the implant body. Crestal
incision and installation of the 4 implants went smoothly. Unfortunately the shortest implants were 8 mm so I had to
perforate the lower cortex. Distal implants are a little inclined to obtain a longer bone- contact and a wider spread
in prosthetical attachment. Uneventful healing and patient is restored with her prothesis at this very moment.
Pressure on the lower mandibular border is sensitive but not painful.
As soon as available I can send the recall radiographs. I have no long-term experience with this mini-implants
(did some 10 cases) but up to now I'm quite happy with the result - Tommie Van de Velde
Tommie, I have a patient similar to this. You encourage me to look at her differently. So far, we told her she would
need to see an oral surgeon for bone grafts.
Now, I must look at her again. I have seen the oral surgeons perf the mandible on purpose to fix some type of implant.
I can’t remember what it was though - Deanny
Interesting case., Do they NOT make shorter implants? Even by another manufacturer? - Joey D
In such cases I prefer press fit implants they have 6mm too and i guess the cutting edge of the threads are too sharp
at the end - Boeu Maghoul
problem with a pressfit in this type situaiton is you wont get primary stability and a threaded implant will offer
this place increase in % surface area in contact with bone. problem also with pressfit is they dont handle shear
load well - Gregori Kurtzman
Only thing I would recommend is make sure you have the area on the denture inferior to each "O" ring housing relieved
so that the denture doesnt contact it when inserted or you may find that the mini's will become mobile. I dont think
perforation of the inferior cortex an issue in this case and should heal with bone formation over the apical as
initiated from the periosteum - Gregori Kurtzman
two comments here tommie. #1. the overextension should be of no consequence, unless the patient can feel the "points"
under the chin. however, an option you have is to cut off a mm or two of the apical portion before placement. #2.
i hope this works out long term, but i think you would have been better off placing the distal fixtures more parallel
to each other. the divergent path of insertion is going to place a lot of lateral stress on the distal fixtures during
insertion and removal, potentially increasing wear on the attachments, and more importantly, potentially hastening their
demise. how long has this case been in function? - gary
With that I agree, Gary. I've seen these mini implants placed directly into the sinus with not lift. The claim was that
the perf was so small that it would heal without a sinus lift. I struggle with that. Guy
Actually, we use a fair amount of the transitional/ mini types of implants, and in the situation tommy was faced with,
the only way to do anything else was large scale grafting. If the patient declined and was a poor candidate, the minis
are quick easy, and don’t produce massive defects if they fail - Gary
Believe it or not guy, we probably perforate into the sinus more than we realize with 3rd molar surgery and implant
surgery, and most of these are without clinical significance. Take a look at this nobel guide case we have in the works.
This is a sinus side view. Note the 3 silver dots poking through. Those are 3 of the 7 implants we will be placing,
and technically all of them will be a perforation without sinus lift. From an engineering perspective, engaging the
cancellous bone at both the crest and at the sinus border provides more support and resistance to lateral movement than
ending the fixture in medullary bone alone.
Having said this, one has to be careful about taking this to an extreme. I put a 2 inch nail into a wall and do not
catch a stud, I basically have ½ inch of nail stuck in drywall and an inch and a ½ in air space behind the drywall.
By the same token, I place an 8mm implant without lift penetrating 2mm into the sinus, I now have in essence a 6 mm
implant - Gary
That' s it. I don't want to pose this as the treatment of choice. The patient was completely informed and agreed about
the whole procedure with all consequences. This is not something which floats in Europe but came in handy in this case.
Just wanted to post this case as my controversial introduction and start some discussion.
As a matter of fact there is this study in monkeys showing that after perforation of the maxillary sinus floor implant
apices are covered with bone. Can someone help me with this reference? I lost it.
As a matter of fact, we always try to engage the sinus floor with the first drill. Then lift the the membrane by
installing the implant. I ll attach a post-op x-ray of one of those cases: no bone graft used - Tommie
Hi Tommie ,Look at this article in the latest issue of this very good journal- Jacques Bernier
Clinical Oral Implants Research : Volume 17 Issue 6 Page 679 - December 2006
doi:10.1111/j.1600-0501.2006.01264.x Volume 17 Issue 6
Osteotome sinus floor elevation without grafting material: a 1-year prospective pilot study with ITI implants
Rabah Nedir1,2, Mark Bischof1,2, Lydia Vazquez2, Serge Szmukler-Moncler1,2 and Jean-Pierre Bernard2
Abstract
Objective: The aim of the present pilot study was to evaluate: (1) the predictability of an osteotome sinus floor
elevation procedure with ITI-SLA implants without placing a bone grafting material, and (2) the possibility to gain
bone height without filling the created space with a bone grafting material.
Material and methods: Seventeen patients received 25 implants protruding in the sinus. Most implants (21/25) were 10 mm
long, eight were inserted in type 2 bone, 12 in type 3 and five in type 4 bone. At implant placement, the mean residual
bone height (RBH) under the maxillary sinus was 5.4±2.3 mm; it was 5.7±2.6 mm on the mesial side and 5.1±1.9 mm on the
distal side. Nineteen implants had less than 6 mm of bone on at least one side and six implants had less than 6 mm on
both sides. A healing period of 3–4 months was allowed before abutment tightening at 35 Ncm. The percentage of stable
implants at abutment tightening and at the 1-year control was calculated. The endo-sinus bone gain and the crestal bone
loss (CBL) at the mesial and distal sides were measured.
Results: Abutments were tightened after 3.1±0.4 months. All implants but one (96%) resisted the applied 35 Ncm torque.
At the 1-year control, all implants were clinically stable and supported the definitive prosthesis. All showed endo-sinus
bone gain; the mean gain was 2.5±1.2 mm. The mean CBL was 1.2±0.7 mm. Endo-sinus bone gain and RBH showed a strong
negative correlation (r=-0.78 on the mesial side and -0.80 on the distal side). A good correlation (r=0.73) was found
between implant penetration in the sinus and endo-sinus bone gain.
Conclusion: Elevation of the sinus membrane alone without addition of bone grafting material can lead to bone formation
beyond the original limits of the sinus floor. Despite a limited RBH at implant placement, a healing period of 3 months
was sufficient to resist a torque of 35 N cm and to lead to a predictable implant function at the 1-year control.
you get every bit as much bone as you would have placing material into the space. the latter statement you made is the
most correct, the growth related to the amount of membrane release. it is the creation of a space for clot formation,
followed by subsequent mineralization, that does the trick. the implant is irrelevant other than as a support..
having said this, i most always implant "stuff" to hold the space since that is the way i was taught and the way with
which i am most comfortable.
perhaps this reference, which i have somewhere in full pdf and if i find it i shall post, will help. note no difference
between the grafted and the tented side - Gary
Tommie: Your theory is absolutely valid. A number of authors have indicated that they have had success in maxillary
sinus augmentation with a number of materials. Why? Recent research suggests all the material needs to do is prop up
the membrane, create a voide between the osseous wall and the membrane for clot formation, and viola, you get bone.
Terry, if you are still on the list, please repost the case where you did nothing but tent up the membrane with the
implant itself. I think he got 5 or 6 mm of bone formation in that instance.
Graft material are much more like space maintainers and accomplish the same thing. Are those iti’s ? - gary
I'm having an implant in the site of number 3. My surgeon had planned to balloon the sinus membrane and raise it at the
time of surgery. Problem....about three mm's of the floor of the sinuses came out with the palatal root. Had to do site
preparation. Damn, an oral/atrial fistula is no fun. We finally got it closed with bone and membranes. Got about three
more months before implant placement. Guy
Gary, Oxidized implants show a stronger bone tissue response than turned implants in sinus floor augmentation procedures.
Stupid question time-----"oxidized" versus "turned" implant? yo no se lo que esto significa? - KendelG
never a stupid question buddy, you know that. this reference is from the era where branemark was using pure machined
titanium, not used much at all today. virtually all implants are now titanium alloy, and the outer surface, with certain
manufactures exceptions, are titanium oxide, which is in essence a ceramic for which bone has an affinity.
so turned=initial milled or turned on a lathe types like the old mark ii and iii - gary
Thanks Gary! I have to be careful how much I learn, cause then I'll want to be sinkin' 'em ;-)) - Kendel
Gary, You may have answered my question. How much bone can you get by tenting the membrane?
It would be interesting to see post op CT scans of those cases to see how the bone forms in 3D.
Is it a cone right around the implant? Or is the bone growth related to the amount of membrane release?
Any ideas or research on this? - Arturo
with all due respect to whomever commented, the science doesn't bear that out. tatum is only one of several who have
written on it. the entire concept of a gtr membrane is the same, the creation of a space beneath the membrane allowing
for clot formation and subsequent bony fill. if the membrane collapses into the defect, you will gain little. if it
bridges over, or is tented up by a screw head or similar to prevent its collapse, one can expect bone formation.
again, before anyone gets the wrong idea, in my office in my hands, i find the best way to accomplish this elevation and
maintain it is to shove "stuff" in the hole. but i'm using it simply as a space maintainer - Gary
