Inadequate Inter-Arch Space: How Do I Fix This?

Dr. KSC asks:
I placed XIve 3.4x13mm [Dentsply] implants in #22 [mandibular left canine; 33] and #27 [mandibular right canine; 43] sites. Patient is missing #22-27 [mandibular left canine to mandibular right canine; 33-43]. Healing and osseointegration were unremarkable. When I placed the abutments I found that I had inadequate inter-arch space for an ideal fixed partial denture restoration. What can I do at this point to create more inter-arch space?

9 thoughts on “Inadequate Inter-Arch Space: How Do I Fix This?

  1. Thats why its always said that plan your prosthetics before your surgery.. ..

    Never the less, you’ll learn a lot from this mistake and should be in a better position the next time you start a new case.

    For this one you may try custom castable abutments and then have your prothesis screw retained instead of cement retained, because cement retained would require more inter arch space

  2. you should be able to squeeze a screw retained prosthesis into your space. show the case to a skilled implant lab technician – listen and learn.
    what will you do differently next time???

  3. A six unit anterior bridge on natural teeth deserves at least mounted models in the treatment planning stage.
    A six unit implant supported fixed partial denture deserves the same or more, and it would have helped you plan for the correct prosthetic design for your case. You need to.
    In the posterior region, lack of adequate interarch space for a cementable restoration is usually fixed by designing a screw retained prosthesis.
    In the anterior region, however, it can get a bit trickier, since a screw retained restoration needs to have the screw holes come out at the cingulum and depending on the placement and angulation of the implants, you may not have the correct emergence of the screw and may compromise the morphology and the esthetics of the case.
    Another alternative, besides the screw retained option, is to design the case as a deep bite with lingually tipped anteriors.
    Good luck.

  4. You can place a prefab abutment that you had previous adjusted on an analog, and then prep the abutment AND the fixture in the mouth. Make sure to use cord. If the implants are perfectly parallel, then you don’t need to adjust the fixtures, but make sure the lab knows where you want the margin line to be.

  5. Dr Amit is right! Also, these cases have to be prosthetics driven and planned around available bone. And believe me DON”T have a lab technician plan out your case unless you trust someone with less training than you and who will assume absolutely NO liability for bad advice.

  6. As you say there is no space for an ‘ideal’ fixed restoration.Consider an acrylic hybrid type of prosthesis. Whatever you use will also depend on the a-p position of the implants/ ridge etc. I would also have placed at least another implant in this case as I would be concerned about the canilever effect on the lower anteriors.As a surgeon we need to realize this must be prosthetically driven and the input of a technician is very important eg. a preop wax up.
    TEAMWORK!

  7. Question- If you are retoring a six-unit bridge on two 3.4 mm implants, will that be enough for long term stability?. Especially if patient has a deep bite, wherer IO space is not ideal. I thought these deep bite patients have strong masticatory forces than your average bite patients.
    I normally opt for a 4.7 in the max central, and max/mand canine area?. Am I “over treatment” in term of the sizes of the implants?.

  8. If there was enough room prior to implant placement, there should be enough space after implant placement, that is unless the implants were placed supracrestally. In any case your only recourse now is to raise the vertical dimension by restoration of the posterior teeth. As you know a small change in vertical in the posterior will multiply the anterior opening effect so the bite raising will only have to be of a very small dimension and should not create any problems viz a vie over-opening.

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