Generate Surgical Guide for Mandibular Overdenture?

Dr. L. asks:

Surgical GuideI have been restoring simple dental implant cases for 4 years and have just started to utilize CT scans and computer-generated surgical guides. I usually make my own surgical guides for single implants in a partially edentulous arch and rely on my surgeon for the larger cases or edentulous arches.

Is it overkill to obtain a CT scan and specifically the generated surgical guide for a mandibular 2 implant supported overdenture (on locators) opposing a full upper denture?

In the past, I have followed the technique of duplicating the mandibular denture in clear acrylic and fabricating the surgical guide myself. However, the dental implants are rarely parallel and usually are outside of the 10-20 degree tolerance for locators. Any thoughts?

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Filed Under Overdentures, Removable Prosthodontics, Restorative, Dental Implants 

Comments

10 Responses to “Generate Surgical Guide for Mandibular Overdenture?”

  1. Fredrick Shaw DDS on August 2nd, 2007 4:45 pm

    I think there is much to be gained by CT studies anytime you are tx planning an overdenture retained by implant option, especially in the atrophic mandible. I also think the diagnostic duplicate denture can act as a reference or surgical guide. However, the computer generated surgical guide helpful it is more than you need in my opinion. Evaluation of attached and unattached gingiva, the restorative parameters under the denture and a laboratoy surgical guide will determine optimal placement all things I think you can acheive without the computer generated guide

  2. Jonathan Abenaim on August 3rd, 2007 7:39 am

    Do on to others as you would do to yourself. If it is “overkill” only you can decide that. Because it is your hands doing the surgery. I typically get a CT scan on most of my implant cases but have yet to get a surgiguide made. As for the lower implant overdenture you need to see where you want to place the implants. THe surgiguide will make your life easier and the surgery more predictable but will also lighten yours and your patients wallet. You must do what is right. “overkill” can only be defined by your surgical skills and your confidence in yourself. So for someone to say it is or isnt without even knowing your work would be ludicrous.
    Good Luck and Keep on Drilling :)
    Jonathan

  3. Raymond Maturo, DDS, MS on August 3rd, 2007 10:28 pm

    Overkill. With all the choices of different implant shapes and sizes, how many times have you NOT been able to place the implants where you wanted them in cases such as you described? Unless your patient is an attorney (or married to one) a simple panorex and a decent model of the mandible to make a surgical guide is all you need. It is certainly more cost-effective. Use CT scans judiciously. We are long past the days of having to place the fixures “where the bone is.” You can teach a monkey to do an osteotomy, but it takes some commons sense to put them in the right places. I think your common sense will go a lot farther than your CT scans for these simple cases such as you described.

  4. yazad on August 10th, 2007 12:27 am

    Nice posts, I think I agree with Raymond except for the fact that a CT would help better than just a simple panorex

  5. John Ackley on August 10th, 2007 3:24 pm

    CBCT is the new standard of care
    for implant placement, all it takes is one case to go awry and you’ll wish you had used it. As far as surgiguides if you use a decent scan appliance you can convert it and use it for placement very predictably. The piece of mind you’ll get and the ease of site selection and placement will more than offset the cost of a scan.

  6. Tony collins on August 13th, 2007 2:03 am

    ct scans involve a large dose of radiation for a small, though important,amount of information. Try using tomograms shot exactly in the site you wish to place. The cross-sectional view will help prevent lingual perforation. They are cheap and low dosage and when used in conjunction with an opg, give all the necessary information. Use a guide if you wish, though personally I rarely do. Parallelling by eyeball is easy and locators can handle considerable lack of parallellism (up to 30% divergence I believe.

  7. Dr. Kimsey on August 16th, 2007 6:17 pm

    Are you kidding?
    While anytime you can not figure out what is going on it is nice to scan and perhaps make a surgical guide. While I have done both I think that the real problem is:
    “In the past, I have followed the technique of duplicating the mandibular denture in clear acrylic and fabricating the surgical guide myself. However, the dental implants are rarely parallel and usually are outside of the 10-20 degree tolerance for locators.”
    The surgeon who places his implants in edentulous cases. My recommendation is to try to find someone else to place this implants if the surgeon is placing them this far off. Or at least go to the surgeon’s office and assistant him in the location and angulation of the implants.

  8. omsjaw on August 16th, 2007 8:36 pm

    To John Ackley: CBCT is NOT the standard of practice radiologic examination to study the implant site: I called OMSNIC and they confirmed it: CT scan itself is not standard of practice: it all depends on a case by case situation (I also spoke to a malpractice lawyer).
    I see more and more statements like “CBCT is the standard of practice for implant”, but it’s wrong: you don’t prescribe CT of the chest in every pneumonia…..

  9. John Ackley on August 17th, 2007 1:51 pm

    To OMSJAW: then let’s call it the standard of excellence and you explain if something goes wrong and you didn’t use it why the patient didn’t deserve excellence. IMHO it’s not going to wash.

  10. jj on August 30th, 2007 5:41 pm

    The question that would be asked if a problem happens——–Doctor or Dr. expert, are there any current treatment or diagnostic modalities available at the time of surgery that could have minimized or prevented the injury ? If you can answer no- then you’re all right. If not, then there will always been legal wiggle room. However, it all goes back to what is reasonable standard of care. Single tooth, 8mm wide ridge 18mm to the canal on pano, no palpable undercuts, it would be hard to argue the necessity for a CT. I served as an expert on numerous cases, and common sense prevails as long as the case is properly documented, properly informed patient, and a well argued case. I keep in the back of mind with every patient, is this the one that is going to sue (fortunately that day has not come yet—knock on wood).

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