It’s always a good day when a delivery goes well. Just earlier this week I delivered an upper and lower porcelain veneered zirconium implant denture. The prosthesis sits on 4 implants in the upper arch and 4 implants in the lower.

implant denture Zirconium

The prosthesis seated perfectly and  the patient was shocked at how nice it looked. I always celebrate delivery days–and especially for bigger cases that exceed even my own expectations. This is a little video I posted on my Instagram of the delivery:

 

I celebrate because I know that for every success, there is bound to be a challenge. While I haven’t had this happen to my own work yet (knock on wood), I have been seeing many instances of fractured zirconia frameworks. 

Imagine as a patient, paying over $25,000 for a treatment and for it to end up with a catastrophic failure like bar fracture. Delivering big cases is a wonderful thing…but we must be prepared to deal with the complications!

In this case, the patient had 5 implants placed and restored with a zirconium bar. You’ll notice that 3 of the implants are screw retained and 2 are cement retained. The patient walked into the clinic with the prosthesis fractured down the middle and with 4 broken screws. several of the screws were not fully retrievable. Now, after spending all that money, the patient will be receiving a removable implant denture.

Here are some of the basics rules of thumb that I follow to avoid catastrophic failures:

  • Ensure PASSIVE fit of framework over all implants
  • Limit cantilevers as much as possible. I try to limit the cantilever to 10 mm, this is approximately one molar. When anatomical structures limit the positioning of the posterior implant, I place a tilted implant to gain a little bit of distal positioning and I recommend the Shortened Dental Arch concept.
  • Ensure sufficient restorative space (>12mm per arch and maybe more for zirconium). If there’s not enough space, the patient is likely to fracture it!
  • OCCLUSION OCCLUSION OCCLUSION
    • I like to use group function
    • Shallow cusps on molars
    • Make occlusal tables narrower B-L
    • Points of occlusion should be at center of the tooth and on a flat surface
  • Six month recall—FOREVER! At these appointments, I’ll be checking occlusion, cleaning the prosthesis (taking the prosthesis out if necessary and then placing brand new screws), and reinforcing oral hygiene instructions.
  • Occlusal night guard. I make these out of clear, hard acrylic.

There are some tricks but these are the most important points for keeping your implant dentures from self-destructing! I hope this helps!

Good Luck!
Ivan Chicchon

Click here for other cool Dental Implantology Pictures.

Check out my video on How to Make Implant Dentures Step-By-Step:
Part 1: Impressions
Part 2: Cast Verification
Part 3: Occlusal Records
Part 4: Coming up!

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