Platform Switching: Which Implants are Designed for This?
Dr. V., from Spain, asks:
I am an oral surgeon practicing in Spain. Some of my referring dentists have asked me about platform switching. I am more familiar with the surgical than restorative side of treatment. Do all implant brands have the capability of platform switching or are only some implant brands designed for this? Anything I should be concerned about? Does platform switching increase the chance of peri-implantitis? Thanks.
54 Comments on Platform Switching: Which Implants are Designed for This?
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Kris
4/1/2008
Hi...
If You use for exemple implant 4mm diameter and abutment 3,5 diameter-You have -Platform switching-pseudo platform switching.
Biomet 3i implants-Prevail- are designed for this new concept in implant dentistry.
http://www.ncbi.nlm.nih.gov/pubmed/16515092
Kris
Michael Giesy
4/1/2008
The Nobel Active implant has a built in platform switch into the design and the abutment is platform switched as well. Great implant.
Donald
4/1/2008
Platform switching moves the inflamatory zone of the connection between the abutment and implant interface inward, reducing the distance allows for the hard tissue to maintain a higher level of interface with the implant surface. I've seen a new implant by Nobel Biocare that solves the micro gap issue as well as the platform switching, NobelActive.
Stefan Gollwitzer
4/1/2008
Ankylos Friadent Dentsply ( Real platform switch )
and Straumann Bone Level ( Just really new)
Best regards from Germany
Stefan
JW
4/1/2008
3i, Astra, the Straumann bone level thingy, Nobel Active are all designed to platfrom switch.
Dr Tony Collins
4/1/2008
Platform switching is flavour of the month lately but is just an attempt to overcome a design fault that almost all manufacturers have - namely an "open" interface junction. There would not be an inflammatory zone at the interface if it was sealed. There would not be the bacterial leakage if the abutment was cemented into the implant. Sounds radical but it works with crown and bridgework.
Have been using a British system for 21 years in which the abutment cements into the implant and it works like a charm. Another useful function of thei method is that you do not get screw-loosening under cemented crowns. If anything goes it is just the glass ionomer cement so all you have to do is retract the gingiva and recement (and check the occlusal problem that caused the debonding).
vsmohan
4/1/2008
any comments on the bicon implants.. a good seal is obtained to keep the inflammatory zone away..
SMSDDSMDT
4/1/2008
Dr. V In what situations does your restorative dentists request this medialized abutment connection? When do you feel that this mode of connection is MOSTessential?
michaelp
4/1/2008
Another benefit of platform switching, from a physics perspective, is lateral stresses are not concentrated at the coronal aspect. I believe Astra solves this problem best with it's parallel walled internal connection. I believe Dr. Colwan (sp?) from OK is working on an internal connection collete system and a cementable platform, whereby the implant has ferrule and the abutment (parallel) acts like a post. Thus, all forces are transmitted evenly down the implant.
Can someone clarify my comments?
T.V.Padmanabhan
4/1/2008
On mechanical aspect of platform switching,we have done a stress analysis and found there is a perceivable/significant difference between switched and non switched forces transmitted to the bone interface and with in the implant favouring the switched situation.Most interestingly the angled switched abutment with st.forces is more favourable than the switched st.abutment giving a clinical clue that when ever we use angled abutments, it is preferable to switch platform
KWT_doc
4/2/2008
Hello,
beside some already mentioned systems the 2007 launched German implant "IQ:NECT" (by Heraeus Kulzer) has a real integrated platform- switching built-in as the internal connection of implant/abutment is independent of the diameter.
This screwless system shows a monoblock-analogue connection. The massive abutments can be individualized by the lab to fullfill even difficult esthetic requirements (e.g. high angulations) without the known limitations of the screw channel.
Dr F Claassen
4/2/2008
The goal of platform switching is to prevent the (previously) normal bone loss down to the first thread that occurs around most implants, thus enhancing soft tissue aesthetics and stability. One of the main causes of this bone-loss is the bacteria that lives in the micro-gap between the implant and the abutment and the resultant inflammatory zone (as previously mentioned). Platform switching by using smaller diameter abutments moves the micro-gap and inflammatory zone away from the bone, thus minimizing bone loss. Another method of platform switching and eliminating bone loss is the type of connection. Parallel or tapering implant-abutment interfaces (Ankylos, Bicon, Astra were the first to do so in the 1980's, and since the patent on that type of connection expired, Straumann and Nobel Biocare also have followed suit with tapering interfaces) automatically platform switch providing the the advantageous decreased transmission of forces at the implant bone interface. The other advantage (proven in the older systems, I've not seen independent research on the new ones) is that the micro-gap is virtually eliminated (it is smaller than the bugs that want to live there). This leads to almost no bone loss around the implants resulting in better soft tissue aesthetics and decreased likelihood of peri-implantitis. Is is a huge paradigm shift (it was for me), but the results are mind-blowing.
L. Scott Brooksby,DDS, DI
4/2/2008
Flavor of the month. That sums up the concept. Where are controlled clinical studies that show this to be a valid concept? If my "gap" is .2 mm further in toward the center of the implant how does that make it better? Since when did cement stop bacteria. That is like saying my crown margins are wide open so I fill them with cement and now they are ok. I have had patients that have had wider diameter implants, especially in the molar region, that were platform switched and with the reduced support the crowns kept coming loose. The actual cause was a poor fitting crown, but the point is that this is a theory, not a fact.
There are those that say that the new microthread stops the bone loss. Lots of Theories, but no hard science. Probably because it is next to impossible to create studies that work and get them funded.
Dr. JB
4/2/2008
Another benefit of platform switching, from a physics perspective, is lateral stresses are not concentrated at the coronal aspect. I believe Astra solves this problem best with it’s parallel walled internal connection. I believe Dr. Colwan (sp?) from OK is working on an internal connection collete system and a cementable platform, whereby the implant has ferrule and the abutment (parallel) acts like a post. Thus, all forces are transmitted evenly down the implant.
Can someone clarify my comments?
To Michael P:
Yes, Dr. Callan out of Arkansas has designed a system, PerioSeal, which has closed the microgap up inside the prosthetic by manufacturing a ridge on the implant for the crown to sit on...thus a ferrule attachment (patented in US and Europe). The other aspect of the system that I love is the internal collet locking mechanism...it is friction based and when combined with the ferrule it has given my patients and me peace of mind. This greater surface area of contact and the better distribution of occlusal force create a strong connection without a micro-gap that harbors the periodontal pathologic bacteria. With the ferrule attachment, the dental cement, and the internal collet lock engaging the implant, the connection of the PerioSeal Implant is significantly stronger than any standard external or internal hex connection.
I am not sure if they have any DRs in Europe, however you won't be dissatisfied, and the beautiful thing is I save thousands a year by using PerioSeal and get great results....not to say the other systems aren't great because I really like Straumann too, however I don't have to buy a $350 implant and an expensive abutment to get the results the patient wants. Do your research!
I agree with most of the posts here...I have friends that are trying the platform switching and not getting the desired results....good concept on paper, however show me long term studies and then I might start to believe....MARKETING wins with these companies, because as physicans we have become very lazy in reading the REAL research...
rbk
4/2/2008
Using logical thinking, what is the advantage of the platform switch? If the problem is the level of the biologic width, one gets all of .5mm. That is all the microgap is moved. The change in stress at the crest seems to have some science. However if the previous two piece implant with a connection is a problem, we should have millions of failures. The one piece implant like the Straumann, already has the micrograp away from the bone crest and the polished collar gives you 1.8mm for the soft tissue to attach. My take on this concept and the flavor of the day is that we are looking for a solution to compensate for a design problem when a better design has already solved the problem.
steve c
4/2/2008
Dr. Claassen sums it up nicely. Platform switching combined with a reduced or eliminated microgap does work incredibly well when it comes to improved tissue health and contour and reduced bone remodeling around the neck of the implant. All major systems have these implants now(Astra Tech, 3i, Straumann, and Nobel). Astra Tech has over 14 years experience here and their system seems to be one of the best.
To Dr. Brooksby, I say try it and you'll see the results for yourself. If you're interested in minimal bone loss, less probing depth, better tissue contour and healthier peri-implant tissue, you'll like what platform switching and a tighted abutment/implant seal are capable of providing.
SMSDDSMDT
4/2/2008
Scott is right there! How many angles dance on the head of a pin. How many factors determine where the bone ends up around your implant? How do we best support the biological demension? There are so many co-related factors that at one time or another we were all exposed to that relate to maintaining bone height. What about the skill of the surgeon as a very big factor? Design of the prosthetics? Macro and micro geometric design? Nanotechnology? Patient selection? We enjoy great success already, over 96% where are we taking this to? I am all for striving for perfection and settling for excellence. When you add up all the varriables that affect bone height the medialized abutment has an advantage as described above, but what for; that additional .5mm? Where do you need this? To avoid the little black hole? I "think" that it helps and especially in the area of tooth 8@9 being replaced by 2 implants side by side, and in the esthetic zone you may be able to be a little closer together, again to support the soft tissue. Think about just how vital the concept actually relates to our success along with the other factors.
Dr. JB
4/3/2008
I agree there is not a perfect solution in the market, however I do agree with "rbk"....the problem has been solved for the most part, however there are some other factors that assist in this as well. The PROBLEM again is when a major competitor can't compete by designing an implant to mimic the solution of another competitor...the result is they change the subject and create another topic to add to the confusion and take the physicians focus off the other topic....then to add more confusion for other competitors to compete they have to follow suit....it is a whirlwind of GREAT marketing!!!
Study the body and the way it heals....this will tell you all you need to know on what you need to use in your practice....
Again I will say there is no need to spend $350 on an implant to get a great result....I am certainly not using one, and I am not having these problems!!!
SMSDDSMDT
4/3/2008
AMEN
Dutchy
4/3/2008
I don't think that the seal is perfect for any connection in the two stage implant. Since the biological width is blind for vertical or horizontal dimensions, you get a 1mm extra for the biological width by switching the platform. That is the only trick there is. You can sometimes see teh same trick with normal teeth with underrestored margins that are going unexpected well! By giving more dimension to the soft tissue in this way and the interaction between soft and hardtissue on cellular level you get a strong tissue and the better stress distibution will give less resorption from the bone as well. Otherwise with no microcap all the one piece implats should do far more better then two stage implants
SMSDDSMDT
4/3/2008
I agree that with an interferance fit and virtually no micromovement between the abutment and the platform you will reduce or eliminate hydrolic pumping of endotoxins into the bone otherwise making unfavorable circumstances for the bone. Furthermore, using the medialized abutment moves the microgap away from he bone by some deminsion which again removes unfortunate circumstances for the bone. However, to say that a one piece design implant/abutment will do far better than the two stage design is not logical.Don't we all see 98% success after years of service. Back in the 60's Herb Shielder fromBoston said they were getting nearly 100% success with silver points for obturation. A few years later he stated that they were now using gutta percha cones and even doing better! How good is good enough? There is a time and a place for the switch. Otherwise the value is limited. Its a good thing to be used considering patient selection.
Dr.Serge
4/8/2008
If thinking about an abutment narrower than the implant diameter then you should add the Zimmer Screw vent 4.1mm to the list of implant with the switching platform principle because it use a 3.5 prosthetic part.
peter fairbairn
4/8/2008
Bone loss is a bio-mechanical and stress management issue not bacterial...
Fadi
4/8/2008
it is funny how 3i calls it platform switching and nobel calls it platform shifting...
Dr. Pinto
4/8/2008
Also with MIS Seven 4.2 and 5mm diameter implants you have plataform switching. By the way this implant has a very good design, incredible initial stability.
jrc
4/9/2008
somebody have experience about gapseal? to reduce inflamation arround abutment and top of implant
dr ACatic
4/9/2008
This is a great topic causing significant number of discussions for over a decade now. Platform switching was first designed (by accident, as many other great things in science and practice) by Ankylos (Friadent Dentsply) and is inherent to conical shape of implant-abutment connection. Most of the stuff is already said in this discussion, so I can only add that one more implant system uses this type of connection (true conical) and implant switching, and that is Ospol, designed by a fabulous little NB renegade team in Sweden.
steve c
4/9/2008
To Peter Fairbairn: You seem quiet definite in your opinion of the cause of peri-implant bone loss. I'm not convinced you're entirely correct and I'm not sure anyone has all the answers at this stage. It does make for stimulating discussion!
SMSDDSMDT
4/9/2008
SteveC: Prosthesis overload>Implant body micro-fracture>Nidus for bacterial invasion>hydrolic pumping of endotoxins>bone loss. Overload and the bacteria are secondary in the etiology. Perhaps, most probable cause for peri-implant disease.
Dr S.Sengupta
4/10/2008
Platform switching is a concept that was accidently discovered by some guys doing research on healing (cant remember the study)
They had inadvertantly left the impression copings on the implants instead of the abutments which are narrower than the implant body..and found some positive results ..so the story goes like all good discoveries !
It addresses 2 issues
1)Medial movement of microgap
Micro gap was historically blamed for bone loss to first thread phenomenon
However ITI had the first one piece implant and claimed no bone loss to first thread ..they seem to have had a point ..however I still saw loss to first thread in many cases?
It may have been due to other factors however
Either way the microgap story in todays hi tech machining is no longer applicable as the accuracy of parts today pretty much eliminated this gap
Its not as if we dont have success with implants with a potential microgap!
2) The second issue is the fact that if the Abutment gets narrow above the bone ..we have more soft tissue
this effectivly allows a good seal around the transmucosal component of the implant
this kind of makes sense as you expose the inside of the body to the outside you want a good seal and a design that encourages more connective tissue is probably a good thing
Bicon have had this concept from the beginning and seem to work well (dont like anything else about their implant though!)
Now it is very fashionable, as it does seem to have a thread of logic
I have no doubt however that this is great marketing material so naturally the companies are seizing on it
For the record IMTEC/Endure also have a platform switch with their new 5mm wide body implant as the same prosthetic components are being used for the narrower implants
Robert J. Miller
4/11/2008
There seems to be a huge disconnect as to what platform is and is not. This term is used collectively to describe both abutment connections and the tissue response. First, let's discuss what platform "switching" really is. When the first Frialit implant was released, it had an internal hex that was interchangeable with all of the diameters. When it became apparant that "accidental" use of a smaller abutment than the desired diameter made for the implant actually preserved crestal bone, we began using this paradigm in select cases. The CHOICE of abutments of different diameters allowed us to switch connections to preserve thin biotype cases in the esthetic zone. The other implants that are characterized as such (i.e. Astra, Bicon, Ankylos) are platform "SHIFTED". There is only one abutment connection at the submergence level and therefore no choice to switch the abutment diameter. The soft tissue response is identical when the implant submergence profile is medialized. I hope that the implant community will begin adopting this new term to more accurately reflect the differences in implant design. RJM
jihad abdallah BDS MDS
4/15/2008
I do agree with dr robert miller where bicon ,astra & ankylos have a shifted platform that really works . I think the reason behind the success is bifold : design of connection + the friction fit joint . doing the switching platform connection with a slip fit joint (where there is space between components leading to micromotion & bacterial pmping ) will not prevent crestal bone loss and will be of no benefit .
Jeff
4/16/2008
The Neoss system has built in platform switching as they have only one platform. All fixtures wider than the 4.0 (4.5,5.0,5.5) by definition platform shift. I pretty much like all the features of this fixture.
Gerald Niznick
4/26/2008
Perhaps the first platform switching implant was the Core-Vent in 1982 because it had a narrow post cemented into a wider implant. The only thing that has changed since then is that 3i, using a wider implant to reduce screw loosening with external hex implants, but not having all the abutments of a matching diameter, started recommending their standard abutment and came up with a story (platform shifting or switching) to claim that this misfit in diameters actually served a purpose of moving the micro-gap away from the bone. The junction between the abutment and the implant, called Micro-gap, by some, is not a problem if the joints stay together. With external hex connections, this was not as predictable as with internal connections and a loose connection can cause bone loss, but really bone loss is more related to how thick the labial plate is at time of implant placement (Proven by VA Study, JOMS Special Issue).
Dr SDJ
5/18/2008
I agree with Dr's "Dutchy" and Dr Robert J Miller's views.
If it was all about just microgaps and pumping of toxins etc, use of "one piece implants" would have been in vogue and two piece out moded as there would have been no connection to speak of.
Obviously the narrowing of the connection creates a thicker gingival collar with greater resistance to masticatory forces and greater resistance to bacterial ingress. Over the years the machining of "hexes" might have undergone huge improvements with many minor alterations in there too.
It's not about "cold welding of implant abutment with zero microgap and stopping of micromovements and bacterial pumping " it all sounds like marketing crap to me.
Platform switch obviously works due to what it allows the gingiva to be rather than the microgap elimination, medialization and stopping of micro pumping of bacterial toxins.
Thanks to Dutchy to bring in the most convincing arguments I have seen in a year over this platform switching issue.
Dr. Vijay Armitraj
5/21/2008
So the question is: if platform switching or shifting works, will it prevent the 3i implant from losing bone to the first thread?
The platform switching on the 3i is a stupid design, because a 4.1 mm implant has a 4.8 mm platform (and a 4.1 mm abutment), which in my opinion has to looked as 4.8 mm implant, because that is the measurement that I use to determine if the implant is adequate to the site. Why not use the Frailit concept where the platform of the implant and the diamenter of the implant are the same and just use a smaller abutment?
Dr. Mehdi Jafari
6/6/2008
Hello everybody. Has anyone of you gentlemen or ladies have any information about a new brand of implant made in South Korea by the name Implantium or Dentium. Some people who have used it are very satisfied with its handiness, low cost and predictibility. I have heard that it is using the platform switching in its design but I am not so sure. Thanks.
Dr.Sazvar
6/9/2008
Dear Prof.M.Jafari
During last 2 years I have been inserted 20 fixtures.
It works good.In september,2008 the main company will provide an apportunity for teaching this systems in Seoul.If you like to participate in this ferrum,I can tell some information.
Best Regards
Dr.Sazvar
Don Callan
6/30/2008
To Dr peter fairbairn, Bone loss is Bacterial, There are other factors, but the # 1 cause of bone loss is Bacterial!
PJ
7/14/2008
Dr. Niznick,
I like your implants and agree with you on most issues but I think you're wrong on the platform switching concept. Sure, the thickness of the labial plate is very important and probably helps to minimize bone loss of implants that are not designed for platform switching. But, there are many cases where there is a lack of B-L width and, in those cases, I want every advantage I can get. What I'm really asking is "When will you include platform switching abutments for the screwplant so we don't have to buy the legacy abutments just to platform switch?" I hate paying 85 bucks for a separate abutment and throwing away the other one.
IMO, you would have the best implant system on the market if you did this. And, yes, I only want to pay $150. Thanks in advance for making this change :-)
Dr. Xabier Arevalo
8/28/2008
I think there is another important factor that is not metioned , and that the most important factor to maintain bone be it with platform switch o with any other is tissue thickness and hieght , be it hard or soft tissue, hard tissue is very clear to everyone a thick bucal plate is a dterminant, but even with a thick bucal plate , bone will be lost if there is aleast 3mm of gingiva, a good example is that if we place an implant be Astra or 3I or what ever in the partially edentulous posterior mandible o a patient that uses a removable prosthesis ,where there is normally very little attached gingiva, Ive noticedthat as soon as you uncover it , and load it , bone is lost if there is not 2,5-3mm on top of it. Platform swithching dose help in "augmenting" the thickness of the gingiva around the implant caused by that extra space left by the swithching that is filled by soft tissue, there is also some gain in the height of the area of tissue around the implant and thus augmenting the " ring" of tissue that seal the implant, yet if this height is less than 2,5-3mm bone will be lost.
P.S totally in accord with the opinion that bacteria is not the only answer to bone loss, if it were true hte problem would have been solved already with onepice implants.
Peter Fairbairn
8/29/2008
Dear Don that is like the kart coming before the horse.
Carlos Rico San Martin
5/18/2009
Aqui en america del Sud, especificamente e Curitiba Brasil, tenemos un implante con esa excelente plataforma "platform switch" + coneccion "cone Morse"; se trata del Implante Friccional Biológico Kopp desenvuelto pelo Dr. Gino Kopp; aconsejo viditar su pagina...www.implantkopp.com.br
ERCÃœMENT
6/5/2009
AB DENTAL is platform switch implant and this is very good implant and good choice for AB DENTAL
Dr fereshte
5/17/2010
What is the causes of over loading implant?
Dr fereshte
5/17/2010
switching platform can reduce bone resorbtion due to micromovements also. Beveling the border of the plat form improves the bone gain . It is present in Astra system.I am using Biohorizone lazer lock system . Igot very good result by this system .
Richard Hughes, DDS, FAAI
5/17/2010
Dr.fereshte, The cause of overloading is due to hyperocclusion, occlusal parafunction and cantilevers (mesial, distal, buccal and lingual).
Dr fereshte
5/17/2010
Thaks Dr Richard Hughes
Do you know about implant loading time?
Richard Hughes, DDS, FAAI
5/18/2010
Dr. fereshte, The loading time can be variable. I know immediate loading is in voague, but tincture of time is better.
Dr fereshte
5/18/2010
Thanks Dr Hughes Yesterday I study about Time of loading
I am practicing in Iran . After only two days learning I put one implant in lateral incisor after extraction I never used any bone material . ( oseocare implant one peice ). It is interesting that after two years not only implant is in good and healty situation but also I can see bone gain around it! and After two years study about implantology and attending different work shop in different country I got lot of experience about this course .I am using Biohorizone lazer lock implant .There is no any connical connection but I am very happy about tissue attachment around fixture it is exellent.
Dr jafari I heard about That implant made in korea But I think long study require to prove efficiency of each fixture. After visiting proff jan lindeh in sweden Astra companny .I think at persent Astra Implant Is the best But If Biohorizone think about changing to conical connection and Astra thinks about Lazer lock technique it will be better.I am thinking about my first implant it was one piece I load it after week my patient is happy with a good papilla situation.Just I insert that implant in a anatomic situation of extracted teeth with less injury during Extraction .Dr jafari You can contact Dr ketabi in azad university of khorasgan in Esfehan he knows every think about this type of implant.
Richard Hughes, DDS, FAAI
5/19/2010
Dr. fereshte, I am glad you are having success and fun. You may want to consiter placing a resorbable graft material such as Osteogen in all osteotomy sites, prior to placing the implant. You will have a greater implant to bone interface and you do not have to worry about jumping the gap in extraction sites. I know some people do not like Osteogen, but I have the histology, from a university dental school, to proove that it does turn over to mature bone with time.
K. F. Chow BDS., FDSRCS
5/20/2010
The term "platform switching" may be a misnomer. Misnomer means using the wrong word to describe something. The platform that we are referring to is the round surface area on top of the fixture in which the screw hole for the abutment is located. Branemark set the trend by making sure that the abutment fits exactly over the top-surface of fixture, with the periphery flush with each other......which is a logical decision at the time....and everyone copied him.......which always resulted in a "normal" resorption of the bone away from the junction.
The advantage of "platform switching" was discovered when a dentist did not have the right sized abutment to fit flush with the fixture and inserted an abutment whose circumference/undersurface area was smaller than the platform/topsurface area of the fixture. This happily and unintentionally took the junction/microgap/microorganisms away from the bone and thus to the pleasant astonishment of the dentist after reviewing the xray, showed that the so-called acceptable normal resorption of the bone away from the implant ceased!!
Thus "platform switching/shifting" was born. The platform however remained the same and was never switched or shifted. That is why i think that it is a misnomer, i.e. wrong word. What changed was the circumferential size of the abutment. An abutment with a smaller circumference than that of the fixture was then resting on the top-surface of the fixture.
Maybe the right term should be "abutment downsizing" or "footprint reduction" or just simply "platform mismatch" or "margin shifting" or "green technology" or ..."gum friendly"...or "shy margins"........ oh hack...just call it "platform switching" to comply with the aura of mystery and awe that implant dentistry should continue to have for old times sake!!!!!!
If you understand the concept, then you can easily see which implant system is platform switching and which is not.
There are 3 critical margins in implant dentistry. The abutment-fixture margin, the crown-abutment margin and the emergence margin...altogether is found within the transmucosal passage of the implant.
Platform switching has solved the problem of the abutment-fixture margin. Most savvy manufacturers are all moving towards this design. The crown-abutment margin is still unresolved whether you screw or cement, it still poses an inflammatory problem.
As for the emergence margin.....one solution may be to reduce the circumference by reducing the diameter of the emerging dental implant. But with our emphasis on the "emergence profile" for the sake of aesthetics, it is unlikely to be practiced widely. As the Chinese have a saying.."Oi lang...Ng moi mang"...which translates as wanting beauty even at the expense of life and health.
'Nuff said.
soumya
3/2/2011
Source of micro-organisms and thereby resulting inflammation is definitely one of the causes of bone loss along with biomechanical reasons... lets not forget the role of chemical mediators of inflammation like PGE2 , TNF-alpha and IL-1beta and the like in bringing about bone resorption.
cheenu
9/27/2011
what is size of platform switched abutment in MIS sytem of implants.