Computer Guided Implant Surgery: Is Laying a Flap Really Not Necessary?

I think this is a great question. My personal feeling is that with a CBCT sometimes you can get away with going flapless. The only thing is that the CBCT doesn't give you an idea of the soft tissue. If you don't have enough KG (keratinized gingiva), a flap allows you to manipulate the tissue so that you can surround the implant with KG. How necessary is KG (called Keratinzed Mucosa around implants)? It's up for debate but I know if it was me I would want it. I would highly discourage flapless without a CBCT since you never know how much bone you have just looking clinically. But I'm sure that's up for debate, too.

the main question is if you can qualify the osseous density you can determinate sperimentally when you drill the hole where you will put your implant. i think that any rx digital support can used as a support but the main support for any implant is the taste of the the structure of the osseous side where you want intervenere with your hand and sesibility .

I agree with the two comments above. I really do believe that computer guided surgery are a great method if there is good bone/soft-tissue volume. However in my hands I have had major failures in computer guided surgeries due to inadeqate bone volumes. The disadvantages/risks of guided surgeries (without flap) as I se it are: 1) Violation of the attached mucosa. 2) No grafting possible, no crestal splitting possible. 3) Risk of overheating (cooling is harder). 4) Dose of radiation. 5) Costs. 6) If you lose an implant You might need a new x-ray and surgical stent. Which futher increases costs and radiation. 7) Time (it takes much more time for the surgeon to prepare/perform the surgery. 8) Less "feel" regarding bone quality. I perform about 800 implant surgeres/year and since there are many disadvanteges of guided surgery I perform less guided now than I did previos years. As a conclusion I would like to adress that You need to be a well educated clinician in order to choose the right cases suited for guided surgery. You also need the skills to perform traditional surgery techniqes before You start with guided surgeries. All the best / Erik

Actually the system works most of the time, and you dont really need a flap. Furthermore, most guided systems use a round or circular tissue punch. The problem is that it works in most cases... the rest is the issue, the system is EXPENSIVE for the patient and time consuming for us, I dont really use it anymore, there is no real replacement for experience and skills. by the way 99% of my implants are flapless and one can graft hard and soft tissue, just takes extra work

Hi I think the responses have been excellent. I have been placing implants for 25 years and have found that I needed more experience, not less, in order to do flapless placement. When appropriate flapless placement leads to improved patient comfort. Flapless placement also does not compromise the blood supply. However you will find that flapless placement almost always leads to placing an implant a bit narrower than you would have placed if you opened a flap, (just because you are unsure of the bone width). This may not be a bad thing because there is some data that residual bone thickness around an implant may help improve longevity. At the same time, in the beginning of your learning curve of transitioning from open flap to flappless, you may end up putting in implants 2 sizes too narrow. Cone Beam CT planning and stent guidance is, ( as was said by the other posters), a marvelous tool when you have more than adequate bone. When you have limited amounts even a .5mm misplacement of the guide toward the buccal (quite easy to happen) can mean the difference between success and failure. More and more I am using guides for the pilot drill and perhaps going to 2.8mm osteotomies when I have the bone visualized. You may want to look at the free program Blue Sky Plan from to plan and construct guides in the future. I have a vested interest in Blue Sky Bio, but since the software is free I hope that does not count as promotion.... Best Sheldon Lerner Periodontics

Bone supported surgical guides work quite well and reproduce your CT scan diagnostic plan. You do know the bone density around each implant in Hounsfield units, so there should be no surprise there. When placing multiple implants, the time saving is there however the real benefit is the accuracy of placement. I just finished placing 8 implants in an edentulous maxilla with a Materialise surgical guide. The pin fixation aided the stability of the guides and the time savings was considerable. Much quicker than having to lay flaps. This is my first edentulous guide but my staff and I were impressed at how easy it went. The patient should have minimal discomfort and no swelling. The additional cost for the guide was $650. I believe that most complex cases deserve a CT scan and any risk from the radiography should be offset by the information derived from the study. Hope this helps. GJG

The best computer that processes all the information that you need to know with regards to placement, bone density as well as soft tissue quality and quantity is between your ears. Today everyone wants fast food dentistry unfortunately when it goes wrong are you going to blame the computer. The skill and experience gained by placing implants the old fashion way is priceless. Don't let todays computerization make up for ones lack of clinical experience and ability.

As with most things, this is a tool. You have to have enough experience when the tool is needed and how you will utilize the tool. Often times, in my opinion, these tools are used in lieu of experience and the technology can give one a false sense of security. As with most medical technology, try and find a situation or the proper application to use the tool. However, sometimes tools are created......then people try to apply them to many situations and use the tool as a panacea. This technology is no different. There are indications for its use and other times when it should not be use or is overkill. One should have a good grasp on the indications for procedures and then apply the proper tools to maximize a successful outcome.

I agree with most of what has been said. One issue though is the misconception that you cannot reflect a flap with a guide. That is not true. In a dual scan system (such as Nobel Guide) you simply tell the computer to make the guide to fit on top of the bone. I don't know if Simplant or Blue Sky allows the same thing but I wouldn't be surprised.

I am totally agree with Erik Lennartsson..CBCT scan is a planning device so after you set proper plan you should consider if possible to do guided surgery or not..if not you can go the conventional methots.Computer planning also needs proper education.So I do belive computerize planning of implantology but still using conventional technics as well... Good luck

The concept sounds great. It is possable to trap some epithelial tissue in the osteotomy which will cause the demise of the affected implant.

In the original question you wrote: "Is computer guided surgery always successful to the extent that laying a flap is really not necessary"? Lets be clear - nothing in medicine or dentisty is "always successful". Every new technological advance is a tool to be used within the framework of our evidence based knowledge, learned and aquired skills and experience of what works clinically. I have been using computer guided surgery for the past two years. Today I use it for almost all my implant cases (which is the bulk of my work). I have always worked with a surgical guide stent so the only difference now is that I prepare the implants first on the computer. I come to the surgery "with my hands in my pockets", since I have already planned the surgery, seen inside the bone and done much of my thinking long before an anaesthetic is administered. One of the things that seems to be confused in your question and some of the responses is that computer aided planning and surgery is not synonymous with flapless Minimally Invasive Surgery (MIS). They are mutually exclusive concepts. We know that there is at least a 25% failure rate for MIS so why even attempt it. Surgery is surgery any way you look at it. Lets not work on such a high failure rate. Failures are worse than the discomfort that most patients experience from conventional flap-raised surgery. Raise a flap, work efficiently and be well planned and everyone wins. In summary computer aided surgery is only another tool in our armimentarium. It is not expensive if used correctly. It is not synonymous with MIS. It has numerous advantages for those doctors that are prepared to invest time in the learning curve Have fun using this amazing tool.

computer guided surgeries are safe accurate reliable and easy to perform even for a beginner in implants. A dentist with not so much experience in implant surgeries will not be confident of doing full mouth rehab cases...but the simplicity of the guide with adequate lab support can encourage him to do that.

Dr.Hatchuel, Can you please inform us about the article which states 25% failure for Minimally Invasive Surgery?

I have never performed a Minimally Invasive Surgery. It looks interesting. As per to comment from Dr. Hatchuel experience with failures with MIS,I have no comment other than the failures may be due to the usual causes ie. excess heat, epithelial tissue contamination, over loading, occlusal parafunction, poor bone quality and quantity, implant surface. Perhaps grafting to osteotomy site with osteogen prior to implant placement will improve the success rate and paying attention to temperature, implant design etc.

Regarding the figure of 25%; I am quoting the speakers on the subject at the AAP meeting in Orlando about 3 or so years ago. They were graduate students doing there research on the subject. Okay so that is not that relavent. In fact we know that most of the implant literature (except for a few limited studies) are based on only short term results 1-3 years maximum. That is not good research upon which to base ourselves as a profession. We should be basing ourselves on no less than 5 year follow up studies (not that many are there?) This returns me to the original question asked above and again I want to stress that computer guided surgery is not synonymous with Minimally Invasive Surgery (MIS). In fact one should be differentiating between full cross-arch surgery/implants and localized areas of rehabilitation such as a posterior sextant, anterior sextant or even a single tooth. Each one has different paramaters. Implant dentistry is not carpentry. It is a complex issue with multiple factors to consider. Therefore computer aided implant planning and placement is only another tool in the full spectrum of what we are doing. Lets keep it in perspective and use whatever tools are available to give the patients the best end result without putting them at risk. Thanks for the opportunity to air my views and if they help one dentist or one patient I have achieved something positive.

Dear all: First of all the concept of using CBCT must be realized. its worthy to note that no information regarding soft tissue tickness or shape can be withdrawn from CBCT machines. although several attempt has been made to overcome this issue but to my knowledge we cannot rely on the soft tissue details come from CBCT. it means that several thing must be considered before any flapless surgery; specially in case of using Computer Assisted Surgical interventions(CAS). in order to overcome this problem we need to get soft tissue information in some form i.e. by impression making and overlap this data to the CT data by means of a sophisticated manner.without this we cannot make any surgiguide based on soft tissue at all. in case of density we also need to know that CBCT's cannot determine Bone density like CT's! That means we cannot rely on the data aquired form CBCT's regarding bone density. The density data usually drawn form CT by means of Haunsfield Unit measurement. this mesearment cannot be withdrawn from CBCT data. so it must be noticed that if you want to use flapless surgery by using CAS, you need to send the patient for CT aquisition not CBCT.i hope in near future the problem of soft tissue information gathering be wisly overcome in scientific manner.

Dr Azari - My lab constructs a radiographic stent using a recent impression of the soft tissue surface. The stent has Barium Sulfate mixed with denture acrylic so it can be seen in outline form on the CBCT scan. Then, using Simplant or other virtual image software you can see clearly where the soft tissue is in relation to the bone. Also, the I-Cat CBCT (the only one I am familiar with) also gives the user HU readings on any section of bone you desire. Maybe not as accurate as CT (I've never used a CT, so I don't know for sure), but at least it gives relative density readings so you can compare several areas. The continuing education we all get from this site is terrific - keep up the good work.

OK, I'll jump in one more time. I know most of the dentists on this site don't "believe" in mini implants. However, using the I-Cat CBCT and radiographic and then surgical stents specially designed for the mini implant system I use has given me great confidence that the minis are in the precise correct place with maximum bone volume, even if the volume of bone is minimal. I'm not trying to sell the mini over the conventional, just saying that technology can improve dentistry for any of us willing to try new stuff.

Dear Azari, As Ken Clifford mentioned, one can get the mucosa anatomy by help of a radio-opaque scan prosthesis. Besides, one can get the Hu value from CBCT like CT. Hu value is nothing more than a complicated calculation of grayscale value. However, both CT nor CBCT Hu values are not "very" dependable. They should be used just for an idea of the bone quality; not the exact value. Hu is a machine based calculation system so it can differ from machine to machine, technician to technician, calibration to calibration etc.

Dr. Clifford, just wondering, you mentioned a few days ago that you didn't have god success with using mini implants to stablize upper full denture. Was that with the use of CBCT? JUst curious.

Indeed a lot of good information and comments in this discussion trail. I cannot and shall not comment on any of the clinical aspects surveyed here, but I feel that I need to contradict and rectify some of the statements from Dr. Azari – because they are frequently-heard urban legends: “No information regarding soft tissue thickness or shape can be withdrawn from CBCT” and “Haunsfield Unit measurement … cannot be withdrawn from CBCT data”. As general statements, they are quite untrue - nowadays. It may well be that (i) older versions of Cone Beam Volumetric Imaging machines were not always performing optimally with soft tissues, and (ii) calibration and software of CBCT machines is frequently optimized for bone tissues rather than soft tissues (because that is what most users are most interested to), and (iii) visualization of both soft and hard tissues implies methods and adjustments that (currently) may require mastering the technique above the average skills, and (iv) metal artifacts in the dentition area may confuse the visibility of the gum line, and (v) … (etceteras). But in general detection, visualization, and even segmentation of soft tissues is well within the capability of Cone Beam 3D Imaging technology (a.k.a. CBCT), and is implemented and easily demonstrable in equipment of the last generation. Unfortunately, in this blog it is not possible to post images (an image is worth one thousand words – or more), otherwise I could have shown here images (obtained with our last generation NewTom VGi - on patients whatsoever and without special settings), where not only the soft tissues contour is very well visible, but it is also clearly possible to segment/discriminate among different types of soft tissues (e.g. fat versus muscle). (To be clear, I am not claiming that our machines are the only ones with such capability; competitors’ machines might also have it. But I can only speak for ours). There notwithstanding, the urban legends referred to By Dr. Azari have some ground … in that there are no well-established, consolidated, universally-recognized standard protocols for detection of soft tissues with CBCT in combination with the realization of surgical masks - yet. Surgical-planning software companies, implant vendors, and CBCT vendors are actively working at defining, improving, and standardizing such protocols. Surely the presence of metal and beam-hardening artifacts at the gum line level poses a significant challenge, and the professional will have to use his/her skill and ingenuity to overcome them … as outlined e.g. in Dr. Ken Clifford’s comments and suggestions. As to the accuracy of Haunsfield Unit measurements, I completely agree with what Dr. Ayberk Yagiz wrote - but development work is in progress, and in future we may see CT numbers = local (volumetric radiographic) density in CBCT datasets expressed as H.U. with controlled and good consistency/accuracy. Roberto Molteni, Ph.D. Chief Technical Officer of QR/AFP Imaging/NewTomDental (The first company world-wide to develop, produce and market a commercial dental CBCT)

Sergio - My successful upper removable palateless cases have been in really good bone, using 15mm and 18mm length, 2.5mm diameter minis. placed without CBCT. This was around one and two years ago, and I wasn't using CBCT regularly yet. You are correct in assuming that the failures could have been caused by inaccurate placement rather than micro movement caused by the appliance. What we need are accurate clinical trials with enough patients for scientific validity, not just case studies which most of us are presenting here. I hope some school or clinician somewhere is doing that. Mini implants are not inherently dangerous!

Dear all: it seems that some companies be aware of their pitfalls! frankly speaking CBCT's has never and ever like the competitor CT machines. the concept of these two are very different. although we can extract the sandwich space between Scannoguides and bone( if we called soft tissue) but frankly speaking if we have one or more metallic restoration the CBCT's be in trouble a lot and nothing can be correctly withdrawn from CBCT images. in case of bone quality i must confirmed that HU is the best measurement till today that one can rely on regarding bone density. this is the best method for representation of the quality of bone in the market. The density value's achieved by CBCT's is only derived from some mathematical estimation!. The problem of FOV is another problem with DVT machines. all of these topic must be considered in taking our patient to get CBCT instead of CT. for the time being and for the best result in common dental practice; the patient always have some metallic restoration; and if we want to get the best result with flapless surgical intervention the CT is the best choice. the segmentation process, the quality of density measurements,the possibility of having the best possible output data;i.e. softness for Steriolithographic guides,..... must be considered.although as my colleagues stated these problems can be overcome in near future but today the CT is still better than CBCT for flapless surgical procedures.

Dr I, Read all the comments above, there are some very good ones. There are many factors to consider. Do not rely on just one tool in your practice. There is not one answer for all cases.

Technology cannot replace clinical experience and know how. It is a very usefull tool, however. I am still amazed at how some "simple implants cases" can really turn out to be quite challenging. If you cannot repair a buccal dehiscence with a guided bone regeneration technique or split a ridge, than computer guided surgery may not be for you. Just a thought.

Eric Wallace, You took the works right out of my mouth.

I ve been doing flapless implants,in the majority of cases, for the last 7 years,with great success rate, which the same as when I were reflecting a flap. from my expiriance when it is done with an expert hands,with good paitent selection,flapless implant are great for paitent and doctor. how great it is to finish a full arch implants for an old or medically compromised paitent ,with only 20 minutes,and with v, minimal side effects. this is like magic. bare in mind that in each case when in doubt ,you must immediatly reflect a flap,and never leave it to chanse,but this cases are v,rare.

There is never a time for "flapless" surgery, even if there is a ton of bone, raise even a small flap so that you can see the bone surrounding the entire implant, Buccal, Lingual etc. It won't be any less painful for the patient and really does not cost you more time or money, but it gives you more confidense that you have bone surrounding the entire implant. And more importantly that you are not doing anything blindly. Do it right lets keep a good name for our discipline and keep you liability down.

if you really want to get advantage of your CBCT and want a flapless surgery at most of the time my advice is to use robotic navigation instead of navigation with plate.you may visit monadent web site and understand better

What about systems like easyguide keystone dental whist acuracy seems to be higher and ver Moreau reliable than simplant and Nobel guide concept ? What about strauman or med3d concept where the radiographic guide is preserved to be modify to a surgical guide thanks to a milling machine. Reliability is known to be 100% with such systems ! Then, I use to do 100% flapless surgeries for at least 4 years and almost 100% of sucess. But it seems to be a european , furtermore, german concept !