Trouble Getting Primary Stability

Implant stability is normally assessed as a torque value during delivery of the implant. Arbitrarily, 35N is a value that has been reported in the literature (although other values are found). Most areas with sufficient bone or in D2-D3 bone quality, this value can be achieved. If you are in D4 bone, it may be a good idea to osteotome (condensing the bone)the site instead of using the drills after your pilot. If you can't achieve primary stability in D2-D3 bone consistently, then maybe the implant system or technique you have is flawed. I haven't used Bicon so I will not pass judgment on it but I have found primary stability using Zimmer, biohorizons, Replace, astra, and 3i easier than ITI Straumann because of the thread design. A tapered implant may be helpful to get mechanical locking, helping implant stability. In cases with concurrent grafting, implant stability is more difficult and shouldn't be an issue anyways since you don't want to load these at all. Also, I am interested in your splinting technique. I have not seen implant fixtures splinted to adjacent teeth in a nonortho related case. In my estimation, staging the implant would be more beneficial than splinting the implants in order to achieve stability at Stage II.

Not having used Bicon , but I thought that primary stability was not an issue with their use? Splinting to adjacent teeth is best avoided as the teeth will move in the PDL and lead to micro movement of the implant which is not good for integration..

There are only 3 things that will kill an implant success 1. overheating the bone 2. failure to get primary stability 3. overloading When I developed the Tapered Screw-Vent in 1999, I also developed a specific surgical protocol using straight drills. In soft bone, the protocol specifies that you stop at the intermedite drill, which is wider than the narrow end of the implant, (2.8mm drill for a 3.7mmD implant, 3.8mm drill for the 4.7mmD implant). By inserting the narrow end into this hole, and slowing expanding the bone (implant is evenly tapered from bottom to near top), you expand and compress the bone increasing initial stability. Studies (Shalabi COIR April 06, showed that this will increase initial stability but also increase bone contact and removal torque.) In dense bone, the protocal specifies that you use the final sizing step drill (straight but steps in the bottom 3mm - 3.4mmD drill for a 3.7mmD implant, 4.4mmD drill for a 4.7mmD implant). Since the socket created by the final sizing drill is almost the size of the outside threads, no bone tap is in dense bone. Most startling about this procedure is that the torque generated in balse wood (soft bone) for insertion of a 3.7mm (2.8mmD Hole) is 3.9in/lbs while the torque needed to insert an implant into oak (hard bone), is only 50% greater.. 6.3in/lbs. I have incorporated this drilling procedures in my new Spectra-system implants (7 designs all with the same body) and they can be inserted using Zimmers Tapered Screw-Vent drills (except for 5.7mmD implant). Implants tapered only at the bottom like 3i and Replace have all their taper in the bottom few mm so they may compress the bone too rapidly and excessively. Implants like the Replace also need length specific drills. THE SURGICAL PROTOCOL MAY BE FAR MORE SIGNIFICANT A FACTORY OF SUCCESS THAN ALL THE CLAIMED VARIATIONS IN SURFACE TREATMENTS.

Splinting implants to teeth to achieve primary stability........ is one of the weirdest things I´ve ever heard. It doesn´t make any sense, Do you really think you are getting better stability with this method? A tooth is mobile itself an every time it ocludes it will have 3D movement, so I think you are trying to build a house on a swamp. Whenever you place an implant in poor quality bone you will have some lack of primary stability, you can improve such situation underpreparing the implant bed and leaving the implant covered by soft tissue (2 staged approach). This will be better than using an osteotome technique . "Shalabi MM, Wolke JGC. Histological evaluation of oral implants inserted with different surgical techniques into the trabecular bone of goats.Clin. Oral Impl. Res."

Re: Primary stability when placing Bicon implants. Bicon implants are somewhat unique in that they are a press fit system, which does not utilize a screw for primary retention, thus you can't use the standard torque gidelines for assessing stability. Essentially, if you are not achieving primary stability, your site preparation is too large for the implant diameter that you have chosen and you need to use the next larger diameter implant in your preparation. The preparation needs to be very precise, without allowing the drill to wobble or overprepare the site diameter. If you are working in D3 or D4 bone, there is a greater potential for over preparation and you need to consider underpreparing the site by one drill size (0.5mm). When you place the implant in a properly prepared site, there should be a slight friction fit, but not enough resistance to prevent you from tapping the implant to place. If you are in denser bone (D1 or D2) and the implant does not seat to depth with gentle tapping, you should remove the implant and use a hand reamer to slightly enlarge the preparation to the next size. This should allow proper seating. If the bone is soft or there is any question about primary stability, you cannot do a single stage procedure and should bury the implant for 3-4 months. Initially, I think that placing Bicon implants can be somewhat tricky and technique sensitive. If you don't have a lot of implant experience, you might try finding a periodontist in your area who places Bicon implants, for some one on one mentoring or just refer the case to someone experienced in Bicon placement.

When you are placing an implant in poor quality bone,you'll notice lack of primary stability, you can improve this situation underpreparing the implant site and placing a Nobel Biocare SPEEDY implant. With this implant, You will always achieve primary stability in every type of bone. And you can do Immediate loading in almost every cases where you use this implant. Best to your new Immediat FUN_ction !

Hmmm............not a good idea...........should NEVER be necessary!........something's seriously wrong with this picture..........must research further!

Splinting an implant to a tooth, to increase stability, makes absolutely no sense. I don't understand how you even rationalized this technique. I feel we are being put on... it's just so crazy. If you are for real just bury the implant under the tissue...

I am sure either you are kidding or doing some kind of research work on dogs.Let us know your results and conclusion when you are done.

Mr. Satish Joshi is one hundred percent right and I think that splinting an implant to the adjacent tooth in order to get the primary stability is something that shouldn't be done even in experimental animals, because the teeth move within their socket themselves (sometimes up to 80nm) and this movement is very detrimental to the osseointegration of implant. Of course there are some devices called implant stabilizers (very similar to rigid fixation mini-plates) that are being used when placing implants in the posterior maxilla and into the antrum in cases where the sinus floor bone thickness is not sufficient to give the primary stability to multiple implants in that position.We should never forget that these stabilizers splint the implants to each other and not to the adjacent natural teeth, and they get their anchorage from the bicortical bone that forms the maxillary sinus floor.

I deeply regret the error in the former comment.Something has skipped out from the fourth line between the parentheses. The corrected text is ;because the teeth move within their socket themselves (sometimes up to 80nm is the maximum tolerable movement for an implant within the bone)and..........Please accept my apology.

A number of my colleagues using the bicon implant system have had similar problems when trying to place an immediate function implant. If you look on the bicon website it actually shows many cases where 'stabilisation' is recommended by bonding the provisional restoration of the abutment to the adjacent teeth! In some cases adjacent crowns have even been burred to aid retention of the resin bonded splint. This is very unpredictable 'messy' dentistry and leaves the dentist and patients relying more on hope than sound evidence. In trying to keep up with other systems bicon are recommending techniques to make up for their no screws system. Their system may simplify the restorative phase and work well for a 2 stage techique but if you begin to have failures the use of ligature wire for stabilisation may leave you open to litigation.

this all sounds very scary to me...a bit like a step back in time...back to the 70's!!!

Dear All, I place Bicon implants as well as Astra implants and Ankylos implants. I have placed over a thousand Bicon implants (all documented, so that's a REAL thousand implants). Bicon implants are strange, odd, bizarre and kooky. They are push-fit implants ("hey, didn't they go out with the Ark?") and therefore get no primary stability when you place them - they are all "spinners", in fact they're all "pusher-in-and-outers" (if that's actually a phrase). On insertion you can forget your Ncm - they have effectively zero Ncm.... ...AND YET THEY STILL WORK REALLY, REALLY WELL. Too long to explain why and I'd need diagrams (which you can't post on this site) to help show why they work when according to "modern implant teaching" they "shouldn't". If you think this all goes "back to the 70's" then take a look at their website (and before you ask, no, I do not have any affiliation to Bicon other than I place their implants - and Astra's and Ankylos'). Their website has MANY thousands of photos carefully documenting hundreds and hundreds of cases. THEY ARE NOT HIDING ANYTHING - just the opposite, they have more documented real cases than ANY other manufacturer out there. Take a look at their "case studies" section, especially their "immediate stabilisation" section, and don't post back until you have, (wow, I sound like my mother!) Kind Regards, Bill Schaeffer

Sorry, that should have read "more documented cases on their website than ANY other manufacturer out there". Bill

I would like to add to what Bill Schaeffer has said above: I have placed hundreds of Bicons (all documented)in the last 5 years and have found them to be absolutely indispensable - particularly when bone is in short supply. We also use 3i and Alpha-Bio and have used Astra and Nobel/Branemark in the past. I have never used wire ligatures to gain stability! If I were to have a tooth replaced, it would probably be with a Bicon implant. We have successfully treated quite a few Dentists and their partners with Bicons and they are very happy and impressed with the results. The system is quirky and initial primary stability is zero but the system really does work and the website is a great educational tool - it has a multitude of cases from start to finish and at review. I find it quite amusing that companies such as 3i, Astra, Osteo-Ti, Alpha-Bio and Nobel seem to be replicating design features inherent in the Bicon design into their so-called new products: Platform switching, locking tapers, large fins/plateau design, sloping shoulders on the implant, Nanotite-type surfaces, integrated abutment crowns.... Unlike Endopore and their short implants, Bicons have a macroscopically huge surface area that allows more mature bony contact with the implant. Unlike Endopore there don't seem to be lots of Dentists upset with rapid bone loss seen in some patients due to the unusual surface that Endopore use - now that really is the 70's! I appreciate that many will find the way the Bicon system works hard to understand and some will find the procedure a challenge at first. But work it does, and very very well.

Primary stability is desirable, but not always achievable or necessary. We have achieved osseointegration in numerous two stage cases without any primary stability. Avoid micromotion and leave nature take its course.

...LET nature take its course...

Hmmm.. splinting with adjacent teeth seems to be "strange" but however, as long as it can help the prognosis and received prior consent with the patient, this "procedure" is somewhat better than doing nothing and saying "it will be fine later..." to the patient. Bicon is simple and dentist-friendly (especially to general dentist). In my limited experience as a general dentist.... regarding the stability, 2 stages procedure is recommended. Under-one-size preparation with tapping in soft bone or "old" extraction site can help. This website is a good place to share experience in professionals. We learn as we earn, we earn more as we learn more.

Bicon implants are very interesting,but i am very skeptical about the crown and implant ratio.Secondly cross arch stabilization of implants is well documented but stabilization of implants with natural tooth for primary stability can cause micro motion because the natural teeth has peridontal ligaments

Bicon has been my main implant system when I first started. I had quite a large number of successful cases with this system. Some were very challenging. Surprisingly, they worked. However, I also had quite a number of unexpected failures. I've come to realise and accept (perhaps a little late) that majority of these failures are due to flaws and limitations in the system. True, Bicon implants do not require primary stability to integrate. It almost never fails to integrate as long as you cut the healing plug and achieve primary closure. Even in areas of large bony defects, as long as you cover the graft and implant with a membrane and get good closure, a Bicon implant that is just hanging in there will most likely integrate when other systems won't. However, the same rules apply to Bicon if you do a one-stage surgery. Many people who have done one-stage surgery with Bicon are shocked that their implants fail even in excellent bone. Most of these failed implants are short 6mm implants. It must be noted that the osteotomy one prepares is the same size as the implant. When you do a 1-stage procedure, you knock a healing abutment into the implant well. What does a knock like that do to an unintegrated implant? It may cause it to lose whatever stability it had. That's why so many apparently straightforward cases done with Bicon can fail. A short and wide Bicon implant is almost like a ball of titanium. There is not much physical retention in the shallow osteotomy. A knock will easily displace it from the original position. Without primary stability and primary closure, soft tissue will infiltrate and cause the implant to fail. 1-stage Bicon procedures only work well with long, narrow implants which are not displaced when knocked with a healing abutment. I seldom use Bicon nowadays after having horrible experiences with it in cases involving ridge splits and sinus lifts. My cases are now more complex and the Osstem GS II is my most used system these days.

One can splint implants to teeth for primary stability. This is an old technique. The Bicon works best if burried and exposed later. I like the implant, but you should not try for inital stability with this implant exposed. You want inital stability by way of a good implant to bone interface. One does not usually get this with the Bicon.. Look at Dr. Niznick's remarks. He is on the money.

I think Bicon implants should carry a warning label that says no one-stage surgery for implants shorter than 11mm. This will curb a lot of the unexpected failures. Another problem lies with the restorative aspect. Restoration of upper anteriors is very technique sensitive. If you have to use angled abutments, it's one major risk of abutment dislodgement if you do not tap accurately along the long axis of the implant. With tight proximal contacts, it's another risk of abutment loosening. Protrusive movement is also a problem. Most patients will try to avoid contact with the new crown when you're trying to check for protrusive, giving you an underestimation which can have disastrous results when the patient grinds his teeth in sleep. When you pull and push the abutment in and out of the well to make adjustments and the soft tissue bleeds, you have another problem on your hands. With a rather crude abutment orientation gig, it may not be easy to seat the abutment exactly in the position as that on the model. With conical abutments anteriorly, it's not a problem. The crown still fits. With much wider abutments in the posterior, a tiny, undetectable 1 degree error in abutment seating (which can occur since the abutment can rotate 360 deg and seat in almost any orientation) can result in a less than ideal fit for the crown. It's not like implants with a hex system where errors in abutment seating are obvious and easily corrected with a small turn to the next notch. This problem may be solved with extraoral cementation. However, another problem - proximal contacts will prevent the abutment from seating completely. Checking for proximal tightness in the anterior is quite simple. Doing it for posteriors is a nightmare unless you have tiny hands or very long fingers. Bicon worked for me when I had few implant cases and a lot of time to spare. Not now.