Surgical Stents for Implant Placement

Harold, a dentist, asks:

I have begun to make surgical stents for my surgeon to guide the placement of dental implants in the maxillary aesthetic zone. There is some controversy over where to place a dental implant for a maxillary central incisor and what inclination to use.

I am making the stent to place the long axis of the dental implant so that it
passes through the cingulum. I am locating the dental implant to the lingual
of where the natural tooth was located to preserve the
buccal cortical plate.

Some authorities, though, recommend orienting the implant so that it passes
through the incisal edge of the natural tooth. What are you all doing? I’d appreciate some thoughts on the proper technique here. Thanks.

29 thoughts on “Surgical Stents for Implant Placement

  1. The only reason you should be placing the long axis through the cingulum is for a screw retained restoration in minimal interocclusal space. We have been placing our long axis through the incisal edge or even slightly facial for over a decade. You will find that there are fewer perforations of the facial plate and, with a properly milled abutment (either Ti or Zir), you will get outstanding emergence profile. This is because the implant top is rotated facially and you will have more abutment shoulder to work with. We also exclusively use tapered implants to provide more latitude in angulation of the implant.

  2. as an oral surgeon I have been placing implants in the esthetic zone in the cingulum area and fine much more predictable long term esthetics. Also misch who advocates placing them in the incisal long axis is not showing you his complications of recession of gingival margins and bone loss. the margin of error is too small when aiming for the “incisal edge” and will sometimes result in implants too far labial with the consequences that result. There is more room for angulation correction too when near the cingulum. I think a screw access point though the cingulum has stood the test of time….

  3. According to the latest studies, it is actually recommended to leave at least 2mm of bone facially, if at all possible. There are many reports of late in the literature that indicate that the more facial and facially inclined implants are placed, the more they tend to loose soft tissue facially over time. If at all possible try and place your implant, as your original statement said: Long axis of the tooth and through the cingulum. It allows you the flexibility of making a cement retained restoration, or better yet, a screw retained one which will allow you to “push” the facial tissue and support it with proper emergence profile. Just remember, there is no right or wrong here, just a clinical situation. Do what you are comfortable with and always try to have as much bone on the facial as possible.

  4. I agree with the last post totally. You can go either way, screw or cement retained, with cingulum placement and this method of placement will usually put your facial implant margin 2mm behind the facial edges of the adjacent teeth. This is in agreement with the ITI consensus conference.

  5. and on another note. nobel biocare should not be pushing general dentists to place implants. the complication rate will go way up. Leave surgery to the surgeons. a general dentist doing surgery is a novice playing with surgery. bad bad news for all of us….

  6. As for the surgeon who said that GP’s shouldn’t be placing implants “leave surgery to the surgeons.” The reason for GP’s doing implants as of late is due to the very fact that we have left it to surgeons. I can’t tell you how many times I have to cover up for the surgeon cowboys who misplace fixtures. Your colleagues freehand placement without surgical guides and it is us “novices” who are left with the mess. Why not have better control over the case from the get go. We will be going through the same learning curve as you did only the end result will most likely be more esthetic and have greater longevity.

  7. A well edicated surgeon is a well educated surgeon. The key word being education. Please remember, dental implantology should be prosthetically driven and planning for the long hall. Please review Tarnow’s numbers and remember that bone loss around implants is 3 dimensional, not 2 dimensional!

  8. I was enjoying the posts until I read the uncalled for attack by the so called oral surgeon again and again reminding us how ignorant & unskilled us poor general dentists are.You must really have a chip on your shoulder because the surgeons I know are not intimidated by the implants I place or the impacted 3′rd molars I remove or the sinus lifts that I perform or the soft tissue grafts I place.Frankly my work is judged by my peers & colleagues that often complement my work as perhaps looking better than the cases they get back from their surgeons.The top two graduates one being myself in dental school chose to be general practicioners not because we could’nt get into surgery but we loved all aspects of dentistry.So please do not post that only surgeons should do this and that ,there are believe it or not dentists out there far more skilled than you and I.As far as the original question is concerned,you should place the implant where your diagnostic wax up dictates,and if this compromises the facial plate you may consider bone grafting.

  9. The last post regarding Tarnow’s numbers… is indicative of most of the literature which relates the levels of bone, or implant-to-tooth, or implant-implant relationships using two dimensional radiographs. As I have stated many times, “there is a danger when we are bound by two dimensional concepts in a three dimensional world.”

    Understanding the cross-sectional 3-D anatomy using CT images will allow for an new appreciation of the true volume of bone surrounding our natural teeth. The “Triangle of Bone” is a concept which aids clinicians in determing this available bone – and thus the correct placement of an implant, with the desire tooth position always remaining constant.

    You are welcome to download a recently updated article on this concept from my website, which graphically describes this concept. The original concept dates back to 1993.

  10. As I stated, a three dimensional situation. Also, anyone out there, when I wrote “surgeon” I meant anyone who performs the actual placement…general dentist , periodontist or oral surgeon! Some of the best “surgeons” I know are general (restorative) dentists! I, myself, am a restorative (general) dentist who has been placing implants since 1987…By the way, Scott, I’ve always thought that was a great article!

  11. Dr.Ganz what is your opinion on Nobel guide?
    from what company’s pushing is in fact the lattest trend in implant dentistry.
    Using the surgical guide,expandable abutments
    ( what are the biomechanics behind of it?)
    they state That this is Best system in planning.
    Please let me know what you think?

    Thank you in advance
    confused practioner

  12. The Nobel Guide system has been sued by Materialise, SurgiGuide & SimPlant, for patent infringement. I can’t say which system is better, but one sure does crow as if nothing comes out the other end. When best ever promises don’t quite produce best ever results, Nobel Direct or their Scalloped implant as examples. Nobel followed the idea in the market place and the lawsuit is still pending. With a large chunk of Materialise now owned by DentSupply their will likely be no stomping on the little guy.

  13. The best (only) system planning came from Materialise years ago Dr.Thompson,but you seemed to be too surprise about this!
    Nobel will experience some changes next year and surely the Materialise issue will cause some problems in the “leading,creative, implant company of the world”…what will do the too many relevant doctors when they will experience that Nobel copied the software? I do want to hear that comments

  14. I advise coleagues who want to compare more than a decade old SurgiGuide to the recent NobelGuide system read some literature before making a statement, to see the difference and the precision that allow teeth in (let’s be flexible) an hour and half!

  15. so far in terms of accuracy there is no an article, only the cadaver study by van streerenbergh. please correct me if i’m wrong Dr Mendinga, if there is so please write references to look up, thank you

  16. I agree with Scott Ganz. You want to favor the osseous triangle if possible. When placed immediately the fixture should be held to the lingual side of the extraction socket but the apical end should penetrate thru the apical lingual side of the socket. This can result in the implant pointing thru the incisal edge, but because the implant is pointed into the osseous triangle to avoid the buccal cortical plate not because the coronal aspect of the fixture is brought to the facial. Since there is little difference between delayed or immediate placement with respect to the fixture position the same holds for delayed placement positioning. This is now being better understood, but just consider that placing a ficture into an extraction socket doesn’t change the healing process dramatically. After a few months it’s going to look much the same either way as long as the fixture placed delayed is done in a timely manner. However, with delayed placement 3D imaging helps you visualize the external bony topography and internal bone volume since the extraction socket is no longer available for reference.

    In the future the sloped top fixtures from Astra will allow you to align the lingual side of the implant with the lingual bone level. This simplifies depth of placement and allows you to focus on the ideal fixture positioning as placement depth becomes for the most part automatic.

  17. I agree with the other general dentists concerning the oral surgeon’s inappropriate remarks. I began to do my own surgery when I could not find an oral surgeon who understood the prosthetic requirements of implant restorations. I had too many problems dealing with their poor placement of implants, and ultimately it was my responsibility to deaql with ther patient and the poor result. Now that I place my own implants my results are 100% better. The requirements of the surgical protocall are not as demanding as the requirements of proper occlusion, and esthetics. I mustr add that some of the periodontists that are doing surgery, are very good far better then the oral surgeons as a group.

  18. To the oral surgeon who posted the inappropriate remark, you comment about general dentists placing implants is unfounded and certainly unprofessional. We as general dentists have had to deal with restorative complications from poor placement by specialists for years. I had one tell me personally in front of 10 other people (who by the way isnt a specialist anymore) that
    “general dentists were f—— up the honeyhole for all the specialists!” come-on…take the high road. All specialists dont place implants poorly and I have had MANY in function for over 20 years because they were placed well, BUT…I have had some restorative nightmares from extremely poor placements returned to me “ready to go.” Now, unless a patient has a specific request, I control my own placement. and when there is a problem, I look only in the mirror. The restorative component guides the surgery, not the other way around. Thank god for the specialists AND general dentists who trained me through AAID and ICOI programs. They know the true meaning of being a “colleague” and “teacher”. I just emailed Dr Craig Cooper, past president of the AAID, to thank him for one of his hands-on pearls at the recent AAID bone grafting course. He is truly the type of colleague and teacher we need as implantologists. Maybe you could take an AAID course along with your other specialist and general colleagues and THEN weigh your comments…along with your name. To the other specialists like Maurice Salama, Carl Misch, Mike Pikos, Lee Silverstein, Dennis Smiler and Don Callan (and many others) who effortlessly continue to contribute to the advancement of implantology by laying aside their own personal specialists egos …I am truly grateful. Many thanks. Bill

  19. I have been teaching how to do bone graft procedures and placement of implants for 17 years, and I have seen MANY general dentist to do a better job than some OS and Periodontist. I feel as long as anybody gets the proper training there is plenty for everyone. The more we all know, the better all of us will be for our patients.

  20. For the anterior sextant we rather have a CT available to plan for the surgical needs prior to the surgery and discuss the options with the restorative dentist and patient, with Panex, many times the implant position ends up modified during the surgery. Another thing that I try to do is to plan the surgical procedure when the restorative dentist can be present, so that if modifacations are necessary he agrees on them.

    Another thing I find easy to do, to reduce the possibilities of poorly positioning the implants, is to request the residents and students to make a Surgical Stent using the Straumann’s Drill Sleeve ( with collar and 2.3 mm diam. inside ) and the pins ( Straumann’s ) which can be done in the study model using a Dremmel mounted in a Drill Press ( that comes for it )utilizing the Struamann’s drill ( Thermoplastic Drill Template Set). It works as long as the bone width is adequate and the pins are alingned properly in the vertical direction. This avoids the pilot drill to move elsewhere or change the intended direction, again as long as the Surgical Stent is correctly aligned.

  21. My wife will be having an implant done on #19. The dentist says that he doesn’t need a stent since it is a molar. Is this correct? I was under the impression that a stent should be used for all areas.

  22. a surgical guide which is restrictive is of great benefit in the anterior region. You must prevent movement or walking of the drill and a guide will do this—-the use of a drillstop for vertical control and a guide will help in the 3-dimensional placement. I know promotion of a product is frowned upon–but my drillstop is designed by me a dentist—for dentists to improve placement and increase safety for which we are all striving.

  23. I support 3 oral surgeons and a periodontist. I would recommend a surgical stent in all instances. Yes, with the use of custom abutments you can overcome placement errors (within reason). But I find it no excuse to have placement errors when a stent is provided. Even when the implant is placed in about the right position I often see that the implant is angled in the wrong direction.

  24. After reading all the posts I believe a Stint and drill guide is a must for ANY implant case. I can’t tell you how many times I have to compromise a case due to poor placement of the implant.

  25. Just for clarity, I am going to post what the correct terminology for this stuff is.

    By all means consider me OCD, pedantic etc. but I see incorrect terminology being used too often in implants;

    In implants, a “surgical guide” or “drilling guide” is a device to help you correctly position the osteotomy when creating it.

    A “stent” however is “a man-made ‘tube’ inserted into a natural passage/conduit in the body to prevent, or counteract, a disease-induced, localized flow constriction. The term may also refer to a tube used to temporarily hold such a natural conduit open to allow access for surgery.” This definition is from Wikipedia but no definition that I can find talks about a stent being used for drilling holes for implants. Unfortunately, this incorrect use of the term appears to be popular.

    There is no such thing as a “stint” in medical or dental terminology. In common language it is “a stretch: an unbroken period of time during which you do something” i.e. nothing to do with implants or osteotomies.

    So, perhaps we should stop calling these things “Stints”?

    Right, I’m off to take my OCD meds now!!

    Bill Schaeffer

  26. I personally place them a little lingual.
    Perforation of the labial plate is usually not a problem if you go palatal to begin with and then upright the angle.
    Even if there is a perforation, I would like repairing it at placement and getting a better aesthetic outcome.
    If it perforates labialy, it needed augmentation in the first place (prolly)

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