So I’m currently just a restoring dentist (hopefully placing implants in the future) but this was a first for me. I was delivering a screw retained implant crown with custom abutment for #4 Nobel Replace. Lab said it was too short for a stock abutment. Implant was placed ~10 years ago and he fractured off the porcelain and needed a new crown. Original crown was cement retained and I was, honestly, quite proud I didn’t damage the screw while digging for it (Foreshadowing here…). The bone loss is stable and has been there since the implant was placed!

My lab got the parts through ARGEN IS. Lab sent two screws, one in the package, one in the cast with the crown. Used the screw in the package. Check contacts and occlusion, everything is fine,

but when I go for my final torque, the driver slipped at ~ 20 Ncm. Not good. Check the screw. Might be stripped. Can’t get the driver to engage to back it out and use another screw. Very not good.

Tried another driver, tried wrapping it in teflon tape. Nothing. I used a nobel driver, and I only had to remove once to adjust the contacts. Nothing was over torqued. I’m a rather young dentist and I haven’t encountered a stripped screw that’s brand new. I will admit I’m not super familiar with Nobel (trained on straumann) so I don’t know if this is a brand thing. I informed the patient, covered with teflon tape + composite.

One: What can I do to prevent this?

Two: How do I manage a stripped screw in this situation?

Three: Do I bring him back or just fingers crossed hope I don’t need to go back in any time soon? First time I’ve stripped a screw, so just a mild panic attack over here and not sure if it’s warranted!

Jesse:

I think this complication is far more common than we realize and definitely no need to panic!

Argen supplies a prosthetic screw and a lab screw. The prosthetic screw is usually a darker color and the lab screw a plain silver color. It sounds to be like you possibly delivered the crown with the lab screw and its not exactly rated to full torque. And/Or you were using a worn-out driver that stripped the screw. So anyways that’s why this happened but what’s more important is what to do now!

You could definitely inform the patient. Let them know it torqued to 20 and ideal is 35 and that it may loosen up in the future and if it does to come back immediately. The only danger of this is fracturing the screw head which makes it way harder to remove (but not impossible).

If you decide to attack this now, try a Straumann driver and a 0.50 hex driver from zimmer and really push apically and try to unscrew it. Sometimes the design of these screw heads can engage a stripped screw better than noble driver. If this doesn’t work the next step is cutting a slot in the head of the screw and using a slotted driver to back it out. In the next week or so we will release a short guidebook on the details of how I do this.