Implant Bridge Noob Question (hexed vs non-hexed)

[KentPWalton]

I've done this a couple of times, but only after informing the doctor and getting their permission. The two cases I can remember doing this on were abutments they sent me to use. I already have fought the battle against Straumann in my area and won. If I were to manually adjust an Atlantis abutment in their implant and something went wrong, then they would have ammo to try and trash my lab as they have done in the past.

It would simply be that you would have to fully pay for the new abutment since the previous one was modified when the intent of the product is to be hexed. The product will no longer perform as intended and tested by implant companies per the 510k specifications.

 

[KentPWalton]

Screw Retained - non-engaging components supplied by your implant provider (you can have one site hexed, but all others need to be non-engaging)

Cement Retained - hexed using stock components or custom ti abutments

That simple.

 

[Car 54]

Screw Retained - non-engaging components supplied by your implant provider (you can have one site hexed, but all others need to be non-engaging)

Cement Retained - hexed using stock components or custom ti abutments

That simple.

That works for me, Doc. KISS...lol, the theory, not you

 

[TheLabGuy]

When you adjust the abutment below the margin of the stock component, you then void the warranty of the part. The part was not intended for the hex to be polished off. That is why implant companies offer non-engaging solutions.

When's the last time you warrantied a part?...seriously, this sounds like the OEM vs. compatible argument to me. While any real lab owner knows the lab is always on the hook regardless of some make belief warranty or not.

 

[HonestAbe]

When's the last time you warrantied a part?...seriously, this sounds like the OEM vs. compatible argument to me. While any real lab owner knows the lab is always on the hook regardless of some make belief warranty or not.

I've just been scanning the abutments, 3d printing them, then casting them out of melted down bronze articulators and using those, saving tons of $

 

[TheLabGuy]

This is important, especially if the paths of insertion are very divergent.
But, and if possible, I keep the mesial implant engaging. It gets more complicated to find the path of insertion, the further back you go.

A lot of good things have been said here.

I agree with that and the mesial one being the predominant one that should be left hexed...if it's parallel to the proximal contact. (There, that sounds better)...good stuff @Contraluz

 

[HonestAbe]

The current saga summarized:

Boss 1 says both hexed and had me change the parts I was going to order to reflect that
The forums here says both non-hexed or one of each depending on the case
My dentist father (who started as a lab tech) says both non-hexed (and he's never heard of the one of each way, but is intrigued)
Boss 2 says both non-hexed

The parts came in today and the implants are not parallel, Boss 1 is probably going to have to modify the abutments and/or grind the hex off of one of them. Now that the case is in front of me and I can hold it in my hand and look at it with the abutments in place I think the whole situation makes more sense. They should have been custom abutments and whatever money the doc is saving by insisting on the stock abutments probably isn't worth it.

 

[Car 54]

I've just been scanning the abutments, 3d printing them, then casting them out of melted down bronze articulators and using those, saving tons of $

Or, when I used to be in office, I left a couple of screws and bolts at the bottom of the casting well so I could reply to the Dr when asked, it was in case I ran out of metal when casting.

 

[HonestAbe]

I wonder if there is any kind of like crazy knockoff implant part scene made of terrible materials etc

 

[Labslip]

Boss 1 says both hexed and had me change the parts I was going to order to reflect that
The forums here says both non-hexed or one of each depending on the case
My dentist father (who started as a lab tech) says both non-hexed (and he's never heard of the one of each way, but is intrigued)
Boss 2 says both non-hexed

The parts came in today and the implants are not parallel, Boss 1 is probably going to have to modify the abutments and/or grind the hex off of one of them. Now that the case is in front of me and I can hold it in my hand and look at it with the abutments in place I think the whole situation makes more sense. They should have been custom abutments and whatever money the doc is saving by insisting on the stock abutments probably isn't worth it.

You'll virtually never be able to use both hexed, it's almost impossible to place both implants exactly parallel.
A hexed abutment gets resistance to lateral torque from the hex inserted in the implant. If the hex is missing, those torque forces are all carried by the screw head. A hexed abutment is more mechanically sound. A deep interface like a Straumann or Astra is more resistant to torque than a shallow interface like Zimmer.
Leaving one of the abutments hexed takes some of the torquing pressure off the screw heads.

 

[Labslip]

I agree with that and the mesial one being the predominant one that should be left hexed...if it's parallel to the proximal contact. (There, that sounds better)...good stuff @Contraluz

I've always left the hex on the implant that is:
a. Most parallel to the proximal contact
b. Most distal since it carries the heaviest occlusal load.

I never thought about the difficulty of finding the path of seat. I may have to change it up.

 

[Car 54]

I've always left the hex on the implant that is:
a. Most parallel to the proximal contact
b. Most distal since it carries the heaviest occlusal load.

I never thought about the difficulty of finding the path of seat. I may have to change it up.

In following up with "B" and for anyone to answer. When we do hexed and non hexed together, over time is there a greater chance of screw loosening of the non hexed abutment, especially with patients who may be mild bruxers (keeping them out of occlusion)? Would it be better in cases like those to just do 2 hexed, engaging abutments and go with cementable?

In general, would 2 engaging abutments (cementable) have less of a chance of screw loosening, or are the combination abutments just as "strong", ridged, as 2 hexed? I get the idea of screw retained, in being able to re-torque a screw as needed, but just curious as I haven't done very many screw retained cases, and now have one in the lab with 2 implants at slightly divergent angles.

 

[TheLabGuy]

In following up with "B" and for anyone to answer. When we do hexed and non hexed together, over time is there a greater chance of screw loosening of the non hexed abutment, especially with patients who may be mild bruxers (keeping them out of occlusion)? Would it be better in cases like those to just do 2 hexed, engaging abutments and go with cementable?
In general, would 2 engaging abutments (cementable) have less of a chance of screw loosening, or are the combination abutments just as "strong", ridged, as 2 hexed? I get the idea of screw retained, in being able to re-torque a screw as needed, but just curious as I haven't done very many screw retained cases, and now have one in the lab with 2 implants at slightly divergent angles.

Cementable causes perioimplantist...due to Docs not being able to get all the cement removed...especially with hour-glass shaped abutments. So to answer your question does internal hex strength outweigh perioimplantist? Not sure, would make some good research.

 

[Al.]

Quite often I am asked to make both abutments engaging
Then make Zir frames on top with only one access hole on the bridge and I cement that one on the abutment for the Dr.
The other bridge abutment will just sit on top of the Ti abutment.
No stock only milled Ti abutments.

 

[Al.]

Here is another one from last week
But a stinking PFM
Both engaging one screw retained other just custom abutment bridge is sitting

 

[Car 54]

What I've done in the past with both abutments being engaging with cementable restorations, is to take a photo of the abutments occlusally down on the cast, and send it with the case. The Dr's can scan it and put it in their pt file, just in case they need to drill an access hole, they have an idea of where our abutment hole is. Dr's who have a I/O scanner could do the same thing after they seat the abutments (not all of my accounts have a I/O scanner).

Beautiful work as always, Al
Also a creative way to deal with 2 engaging abutments.

 

[Car 54]

Cementable causes perioimplantist...due to Docs not being able to get all the cement removed...especially with hour-glass shaped abutments. So to answer your question does internal hex strength outweigh perioimplantist? Not sure, would make some good research.

Putting it that way, no, I don't think the chance of perioimplantits wins out. But for sure having properly placed height of the margins on custom abutments would help as far as cement clean up, and using a radioopaque cement.

 

[TheLabGuy]

Putting it that way, no, I don't think the chance of perioimplantits wins out. But for sure having properly placed height of the margins on custom abutments would help as far as cement clean up, and using a radioopaque cement.

That brings up a good point, how many cements are radio-opaque? Most my Docs use Relax luting or Panavia, I wonder...

 

[KentPWalton]

When's the last time you warrantied a part?...seriously, this sounds like the OEM vs. compatible argument to me. While any real lab owner knows the lab is always on the hook regardless of some make belief warranty or not.

If the part fails because the part fails, then report it to the company and they should replace the part at no additional cost. If you have modified the part to have it function as it was not intended, then yes, you own the part and likely the manufacturer will not replace the part for free.

 

[KentPWalton]

@Al. Thank you for the different perspective. That is beautiful work as always and definitely a different way to skin a cat. I like it!