Closed Tray vs. Open Tray Impressions

[PDC]

How many of you request an open tray impression for large implant cases?

I notice that with the closed tray technique the impression posts aren't as stable as they should be...some may be but some can be moved with a very light pressure. Even using caps on the posts doesn't fully prevent this. Considering the amount of force needed to remove the closed tray impression, it would only seem logical that something might get torqued a little too much causing inaccuracies. Then there is always the guessing game of repositioning the posts in the impression.

Even though the open tray is more of a pain to take the impression, it would seem that the removal process would prevent any of the issues associated with the closed tray. I think this should be a part of every dentist's protocol on these multiunit implant cases. What are your thoughts?

 

[sidesh0wb0b]

depends upon material. polyethers tend to stand up far better for closed tray than polyvinyl. and then also it depends upon the type of transer post used. some of the closed tray posts just dont have much for undercuts which make them a bit sloppy it seems.
generally with the proper care in impressioning, i dont see either open or closed being bad....i will lean toward open tray impressions being better though.

 

[2thm8kr]

We prefer open tray here. They are a little more stable IMO. We have also been experimenting with different ways to tie all of the impression coping together on the first impression to aid in stabilization.
Primotec makes some light cured wax bar type shapes. They are formed around the impression copings and cured before the open tray impression. Still not perfect, but closer.

 

[Car 54]

Timely and good thread, PDC. I just had to adjust an abutment and remake a implant crown due to this issue, and it was only on a single unit case. This Dr uses closed tray impression copings using the open tray technique (Zimmer system). I showed him about 2-3 years ago of his need to use the more stable fluted design on the open tray transfers, but he didn't do a thing about it.

In this case, he didn't run enough impression material (Polyvinyl) around the transfer causing it to be a little looser than normal, then I didn't see that it wasn't totally seated until I poured a 2nd cast to confirm the contacts, and caught that it was off. I showed him the case yesterday and asked him to please use the right transfer, to ask the oral surgeons for those transfers, or if needed, I would order them for him (charging him for them).

I do ask my Dr's to use a heavy body impression material around the impression transfers to make them more stable, then use a medium to light body the rest of the way. I believe using heavy body for everything would, or could, push tissue a bit?

 

[PDC]

depends upon material. polyethers tend to stand up far better for closed tray than polyvinyl. and then also it depends upon the type of transer post used. some of the closed tray posts just dont have much for undercuts which make them a bit sloppy it seems.
generally with the proper care in impressioning, i dont see either open or closed being bad....i will lean toward open tray impressions being better though.

I agree with the polyether choice and the type of transfer post makes a difference. A post with more undercuts seems to be a double edged sword because it takes a lot more force to remove the impression. I just separated a closed impression with 5 Branemark implants and it wasn't easy...I can't imagine what that was like for the patient.

 

[PDC]

With the popularity of implants growing, I think more specific protocols in this area will eventually take hold industry wide which will allow for an improved experience for all involved. I don't think the implant manufacturers thought the process through when developing the closed vs. open tray technique. It seems that the closed tray should have been limited to single type units. Of course this is never mentioned in their instructions. Just my opinion.

 

[rkm rdt]

If you notice with closed tray impression copings,the impression of the screw head can sometimes alter the position of the coping when you reinsert it back into the impression.

You may think it is seated properly but the screw may not be tourqued to the exact same position as it was when the impression was taken.

This slight variance is all it takes to throw everything off. Biohorizons are the worse for this.

 

[rkm rdt]

Trios solves this old problem for me.

 

[Car 54]

Also, if the Dr's use the closed tray system, that they need to cover the screw access hole in the top with some wax, before they take the impression. Otherwise, they can get impression tags that unless we pick them out, can cause the transfers to not seat all the way.

 

[2thm8kr]

Trios solves this old problem for me.

IO scanning sure eliminates a lot of the inaccuracies introduced in the traditional methods.
Dying for IO scanners to be reliable enough for full arch situations 100% of the time.

 

[PDC]

IO scanning sure eliminates a lot of the inaccuracies introduced in the traditional methods.
Dying for IO scanners to be reliable enough for full arch situations 100% of the time.

It does eliminate a lot of impression problems but then I encountered a whole new set of problems with the accuracy of printed models...not good!

 

[CatamountRob]

I've never cared for closed tray impressions, I have a lot less problems with cases that were done with open trays.

 

[2thm8kr]

All of my single and multiple single unit implants are done model less.
I still need models for the larger full arch stuff, but have been keeping with traditional methods so far.

 

[JKraver]

We prefer open tray here. They are a little more stable IMO. We have also been experimenting with different ways to tie all of the impression coping together on the first impression to aid in stabilization.
Primotec makes some light cured wax bar type shapes. They are formed around the impression copings and cured before the open tray impression. Still not perfect, but closer.

After that you can use pikuplast to keep implants dimensionally stable after soft tissue.

 

[2thm8kr]

After that you can use pikuplast to keep implants dimensionally stable after soft tissue.

I've tried that with mixed results. Picuplast still strinks a little bit and it depends on how stable the impression copings are in the impression.

 

[PDC]

All of my single and multiple single unit implants are done model less.
I still need models for the larger full arch stuff, but have been keeping with traditional methods so far.

What IO scanner is used and are you doing the crown & abutment at the same time? Any emergence profile issues?

 

[2thm8kr]

Mostly Planscan, but occasionally Trios. I don't do split file abutments and crowns because of the way abutments are milled.
Before attempting to go model less I used traditional impressions with gingiva to judge how the tissue would be displaced
by various designs. I also got to see a lot of them placed and modified my techniques from those experiences.

 

[zero_zero]

If you notice with closed tray impression copings,the impression of the screw head can sometimes alter the position of the coping when you reinsert it back into the impression.

You may think it is seated properly but the screw may not be tourqued to the exact same position as it was when the impression was taken.

This slight variance is all it takes to throw everything off. Biohorizons are the worse for this.

I worked out with my accounts to torque down the impression copings to 10 Ncm... then we do the same...

 

[PDC]

I worked out with my accounts to torque down the impression copings to 10 Ncm... then we do the same...

Sounds like a good idea...so how do you hold the analogs when doing this?

 

[zero_zero]

Sounds like a good idea...so how do you hold the analogs when doing this?

Jewelers vise...