Preparing the Implant Abutment

Dr. F. asks:

My dental implant representative recommends that I use stock zirconia abutments and that I prepare them in the mouth. He says that this is just like doing conventional crown and bridge. I agree with him conceptually. I have a problem though with preparing a chamfer 1mm subgingivally. I am concerned about the debris from cutting the abutment. Can this cause a problem with the gingival healing? And then how do you make an adequate impression of the abutment margins unless you pack cord? What happens if you have a titanium abutment? Is this really as easy as conventional crown and bridge?

19 Comments on Preparing the Implant Abutment

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Dr. Michael Weinberg
5/8/2007
Your implant rep couldn't be more wrong! I am being kind as those are not the words I would like to use. I teach surgical and prosthetic courses and I NEVER prep in the mouth. That is what the lab technician is for! You specify where you want your margin ie. 0.5 - 1.0 mm subgingival. Don't pack cord, use EXpasyl by Kerr. If you have never used it then you are missing out big time. I never pack cord anymore and I take beautiful impressions. Stock abutments are on the decline. The implant companies are making abutments with different emergence profiles and margin positions. Take a proper fixture level impression and then let the Lab tech decide from the soft tissue model what the best abutment is. Tell your dental implant rep to e-mail me if he has concerns with what I have to say.
jeff Krantz
5/8/2007
I disagree with Dr. Weinberg. ON A SINGLE UNIT implant case, where my periodontist or OS sends the case back to me with a fixture in it, all I do is create a finish line, IMPRESS and done. I do agree that I do not pack cord because I do not want to disturb the bone, but if the prep was supra-gingival it is obviously NOT necessary. Most of the time, the preps are minimal as they should be. The best analogy I can make is a cast post. We are not supposed to prep them in the mouth although slight alterations are common.
JOnathan Abenaim
5/8/2007
I cant agree more. there is nothing better that having the abutment in hand and casting on milling the crown to it. Unlike teeth implant dont have PDL's and have no give. SO if the fit is not perfect (especially with temp cement ) it will fall off. Hey someone just went through an implant procedure, if it was you wouldnt you want somthing custom for you as opposed to a part out of the box. Atlantis or Procera Abutments are the way to go. More profitable and better clinical results. It is more profitable because the thing that costs the most is reduced "Chair TIME"""
JW
5/8/2007
I bet your rep wants you to buy a kit with 10-15 stock abutments as well because "it's cheaper than the tech prepping it for you" or "if you place an abutment right away, you can preserve the soft tissue". If you prepped in the mouth, you'll worry about disrupting the periimplant complex with cord, or not getting a great impression,junk flying around, vibrating the fixture, heat transfer, and all sorts of "what if's". Let the lab prep or CAD/CAM the abutment and then fabricate the crown to the actual abutment (instead of a die). Just a thought though.
sousadds
5/8/2007
Your rep has never had to do it in the mouth himself. Even if you use a stock abutment it is so much easier to prep extraorally. Zirconia is much harder than tooth structure and it is important to not overheat it (when you see those little sparks while you are prepping they might look cool but they usually are initiating microfractures).The best bet is to do the vast majority on the lab bench and only do minor adjustments, such as droping the finishing line, in the mouth
ImplantPros
5/8/2007
I bet your rep works for Nobel Biocare. They got tired of selling surgical kits to any and all and now they are determined to sell prefabricated Zirconia abutments to those who bought their surgical kits and all the others that did not. Nothing easier than making an implant level impression and letting the lab do the rest of the work. You can also keep an eye on the technology from 3i where you will be impressing the healing abutment and receiving a custom abutment and a cron back from the lab without even removing that healing abutment.
Osseous
5/8/2007
Okay- here's the scoop on why this is a good idea, but is often misunderstood. The kit that is being referred to is from Nobel- it's called the Procera Esthetic Abutment Selection Kit. It contains as many as 16 premade Zr abutments AND a tool or handle to hold the abutments so that they can be adjusted chairside. There are also protection analogs in each platform size in the kit so that you do not inadvertantly grind the interface area when using this handle. Zr abutments do not transmit heat the way that metal ones do- so the chances of causing any thermal necrosis are limited. If you're concerned about that- or the possibility of contamination of the site with the slag removed during the prepping process, just use the handle and protection analog after marking the abutment in the mouth. That's what they're for. Why is this a good technique? Because the best maintenance of bone and tissue happens when you place the abutment early and never disturb it. This is further enhanced with the use of a Zr abutment because of the tissue's cellular response to it. You begin the healing process as early as possible- and you never interrupt that process if at all possible. I've seen implant cases where the results achieved using this technique rivaled the very best esthetic dentistry in the industry. Dr Sonia Lezei from Vancouver has an excellent presentation on this. The esthetics she's getting will blow you away. It's a sound, solid way to achieve the very highest papillae and the least bone loss. The weak point in the other custom options listed- such as 3i or conventional procera custom abutments, is that they all eventually require that you remove one component (healing abutment)to place the final- thus disturbing the healing process, breaking any cellular attachment and beginning it all over again- with the accompanying marginal bone loss each time. I do not work for Nobel- but they deserve credit for bringing this new technique to the market. Based on the results I've witnessed, I believe that in the future you will see this become commonplace in implant dentistry.
JW
5/9/2007
I absolutely agree that if you place an abutment in the mouth and let it integrate you will get the best results. However, you should do it right at the time of fixture placement, when you have highest fixture stability, otherwise you have to prep the abutment in the mouth. remember, the article should that repeated manipulation of the peri-implant tissues leads to loss of 1-1.5mm of tissue height. Unless you are going to place the abutment and torque it to 35Ncm at a point where fixture stability is less than optimal (remember our stability vs time graph), you need to place and torque the abutment at fixture placement or full integration. So by that reasoning, one should not remove the abutment to prep it out of the mouth if it is after integration so as not to disturb the peri-implant tissues. And if you are not comfortable prepping in the mouth, you might want to consider a custom abutment. Nobel should get the recognition they deserve for bringing this technique to the market...like Nobel Perfect, Nobel Direct, All-On-Four, Nobel Guide, Teeth-in-an-Hour (should we go on). All of these techniques showed one common theme, they are technique-sensitive and should be used with caution.
JW
5/9/2007
Sorry about the poor typing ;)
Osseous
5/9/2007
That's why you get the big bucks!~ "Technique sensitive" i.e. being able to properly use a torque wrench? How many highly trained specialists fail at this most simple of tasks? Everything in dentistry is "technique sensitive"... yet it's quite difficult to get folks to simply follow the protocol as it's laid out. If you're going to place the abutment at the time of surgery, you'd damned sure better know what the placement torque value was for the implant- and not exceed it when torqing the abutment screw. 45 is considered optimal for implant placement with Nobel's system, 35 ncm for the abutment screw.- yet based on my observation I'd wager that most clinicians are under the mistaken belief that tighter is better. I see so many tighten the implant way beyond that value~ There is simply no way to mushroom the head of even a narrow platform fixture if you're properly using the torque wrench- yet you read about implant fracture on here all the time. Yeah, I'd call that "technique sensitive"! The clinician was insensitive to the technique!~
JOHN ACKLEY
5/10/2007
Combine the best of the past with the best from the future and you've got the hottest technique going on right now. Pre op models, immediate index, CAD/CAM duplicate abutments, lab processed temp. At stage 2 place abutment and temp to create the ideal sulcus. Upon maturation replace the temp with final crown that was fabricated on the duplicate abutment. Fast, easy, beautiful. SIMPL in titanium or nitride coated surfaces are available as duplicates. As for prepping of zirconia, this is a BAD idea as it introduces microfractures which dramatically reduce end strength. Sure you can do it and lots of people and companies do but the smarter ones have found a way to safely give you exactly what you want and need without field modifications. The Atlantis abutment in Zirconia places your margins at your requested tissue depth by following the exact topography of the tissue and creates the optimal emergence profile with the appropriate taper based on the axial wall height. Parallelism for multiple abutment cases is also flawless. If Zirconia abutments are what you want and you need to sleep at night there is no other way to have them fabricated. When you look at time savings and the results achieved with this abutment it is probably not only much better than what you do now but it is actually available at a similar cost. Don't be fooled CAD/CAM is not CAD/CAM and Zirconia is not Zirconia!! Software for design and proper materials handling seperates the pros from the posers. Try it, you'll never go back!! These abutments are available for the vast majority of platforms on the market.
Osseous
5/14/2007
Wow- there's an add for ya!? You can get a custom Zr abutment from Procera/Nobel via wax-up or cad selection of the various marginal heights and angles. I think you'll find the lead times and cost to be favorable as well. The thread was about the immediate placement of a Zr abutment, however- not second stage as suggested in the previous post. These pre-fab Zr abutments are $289~ I haven't seen Atlantis provide Zr for anywhere close to that cost.
JOHN ACKLEY
5/14/2007
And that is OK that you haven't seen one for that price, and it is OK if you are willing to settle for a "stock" abutment for your patients, and it's OK if you are willing to settle for ballpark placement on a Procera cad abutment or be limited by the technicians experience level on a copy milled Procera abutment because that is what you are willing to settle for. And it is even OK if you want an external hex abutment that uses an adapter to make it fit the tri lobe interface. But if you are someone who wants precision, predictability, strength and versatility then Atlantis is the only answer, and for Atlantis the choice is SIMPL. Make your choice or make your compromise but realize that once you make your bed, you need to lie in it. Keep in mind, haste makes waste.
Albert Hall
5/14/2007
oooooooooooooooooh dear coleague, is your rep who tell you what to do? Why don`t you send the patient to your rep?
Intagrayted
5/14/2007
Wow is Osseous your Nobel rep too? I didn't know he saw patients. Although it does make sense they are trying to do everything else, why not have reps see patients also, after all they say that anyone can place fixtures with a little training, right??!
DB
5/16/2007
Osseous....when last have you had a good look at your periodic table? Do you not know that Zirconia is in fact a metal?
Richard Urban
10/9/2007
Zirconia is a ceramic (Zirconium Oxide). It's Zirconium that's the metal.
dr. nik
2/11/2009
i have used nobel direct and not been happy with it. u prep the implant and make an impression...it can get messy at times. i prefer to use an impression post and send the abutment to the lab tech. the fit that u get on those crowns is beautiful. u can actually probe the crown abutment interface outside the mouth and assure your patient that there r no macro gaps. the gingiva has healed beautifully till then and there is no bleeding on cementation. i dont personally see any advantage in direct one stage implants or preping abutments in the mouth. a two stage technique gives you a lot of prosthetic flexibility too...you can use angled abutments and correct angulation according to the occlusal loads.
S N Nik
3/12/2010
We need to approach it in two angles. 1.evidence-based: the reaction of soft and hard tissue 2. The dentist: we do many types of treatments which other collegues do not agree and vise versa. it realy depends to the type of education of the dentist and the patient needs.So I believe it is not wrong and if you can prepare it in the mouth and use the advantages, why not do it? S N Nik PhD (Dental Implantology, UK)

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