Verifying impression fixtures are fully seated in impressions

[Pronto]

We occasionally have issues with the fixture not being fully seated in the impression. Does anyone have a technique to verify the fixtures are fully seated in the impression? It's frustrating to get that call from the Dr. I use a light touch of water on the impression fixture to help it slide in and wait to feel the snap. Thanks in advance.

 

[JMN]

We occasionally have issues with the fixture not being fully seated in the impression. Does anyone have a technique to verify the fixtures are fully seated in the impression? It's frustrating to get that call from the Dr. I use a light touch of water on the impression fixture to help it slide in and wait to feel the snap. Thanks in advance.

The screw's head where the driver engages will also impress. Use a discoid or similar tool to remove that as it will push back on the impression post.

Sometimes they use cotton pellets to help with this issue. Sometimes the cotton will be in the way too: TIny scisors to the rescue.

Biggest thing of all: Lobby them to stop using closed tray impression posts.

 

[Pronto]

Yes, I've had to snip the screw head nub of before. This mess up was with Straumanns. Sometimes I thing the plastic piece is too tight.

 

[doug]

Ask for open-tray impressions. The docs I work with who have intra-oral scanners are given the present of scan bodies so we can avoid having to deal with impressions.

 

[Pronto]

He does use Itero but not much for implants. We has supplies some scanbodies to him.

 

[Sda36]

Yes, I've had to snip the screw head nub of before. This mess up was with Straumanns. Sometimes I thing the plastic piece is too tight.

I agree with you, if for any reason your insertion path placement is disturbed, you may hang up on the Edge of that plastic box and feel you can't press further but you're shy of seating by that exact vertical height. A real pain, try and ask your Dr.'s to fill in screw head with utility wax before they place or ask them to bevel outwards (V) those Struamann recieving plastic boxes. That would then guide to seat as opposed to Stopping vertical seat. This topic has been a pain for me also in the past, "Blind Faith" isn't the best in implant technology. Blind Faith the album though, Super Classic

 

[JohnWilson]

There are many strategies to limit human error on reseating impression copings. Everything starts with your client.

1) Use the correct coping for the type of impression (some closed tray are way better than others)
2) Use an impression material that has a high tear resistance and time the impression to the IFU
3) When using a closed try coping make sure it does not come in contact or bottom out on the tray (this often leads to tray flex)
4) Have the client take an x-ray and send it to the lab for every case (this confirmation of seat is the first variable to KNOW)
5) Unless the client is affixing the analog to the impression coping before sending you the case tell them not to reinsert the coping into the impression ever.

As for the lab end all the tips here share above my reply have great value, this is what we do in my lab.

1) Compare coping sent matches the coping shown in the x-ray sent. (This helps tremendously when more than one implants are captured with different height impression copings used)
2) Inspect impression with high magnification to eliminate any potential imp material to hold up a fully seated coping.
3) Take photos and communicate potential issues with clients BEFORE you get it returned for rotational issues
4) After model is fabricated we will often slice the impression horizontally through the head of the impression coping to create a window and reseat the impression to confirm visually.
5) Most important for Z axis errors, Visualize the analog used FULLY seats on the coping, prior to pouring the model. Many cheaper analogs will contribute to this error with thicker anodizing/coating and poor quality control but ALL analogs need to be verified.

 

[Contraluz]

with Straumanns. Sometimes I thing the plastic piece is too tight.

I have had this happen, too. On some, I had to apply 'a lot' of pressure to get it seated in the plastic clip. Before I realized there is that issue, i had one or two coming back due to being "high" in occlusion...

 

[Sda36]

There are many strategies to limit human error on reseating impression copings. Everything starts with your client.

1) Use the correct coping for the type of impression (some closed tray are way better than others)
2) Use an impression material that has a high tear resistance and time the impression to the IFU
3) When using a closed try coping make sure it does not come in contact or bottom out on the tray (this often leads to tray flex)
4) Have the client take an x-ray and send it to the lab for every case (this confirmation of seat is the first variable to KNOW)
5) Unless the client is affixing the analog to the impression coping before sending you the case tell them not to reinsert the coping into the impression ever.

As for the lab end all the tips here share above my reply have great value, this is what we do in my lab.

1) Compare coping sent matches the coping shown in the x-ray sent. (This helps tremendously when more than one implants are captured with different height impression copings used)
2) Inspect impression with high magnification to eliminate any potential imp material to hold up a fully seated coping.
3) Take photos and communicate potential issues with clients BEFORE you get it returned for rotational issues
4) After model is fabricated we will often slice the impression horizontally through the head of the impression coping to create a window and reseat the impression to confirm visually.
5) Most important for Z axis errors, Visualize the analog used FULLY seats on the coping, prior to pouring the model. Many cheaper analogs will contribute to this error with thicker anodizing/coating and poor quality control but ALL analogs need to be verified.

Thanks John for your tremedous insight on this as it definitely has a tremendous impact on our abilities working with our clients. This is such an important discussion to have as we become "Guinea Pigs"over the years with what implant companys produce and disperse via their reps. I have so often wanted an Xray of an impression to verify full seating of the coping. Much appreciated for your thoughts and suggestions, hope all is well with you on all fronts down there

 

[Pronto]

We got all the items back. Included in the box was a Straumann card with the plastic pieces that snap on top of the fixtures. Looking close inside the impression we don't see the brown color. Don't know if they stuck on the fixures and pulled out of the impression? The bottom of the channel is hard so it's also possible he forgot to put them on and the fixure heads are resting on the tray. Bringing everything up to him today to show what we have. I bet he never did an xray to verifiy they are seated. I'm not liking these BLX style implants at all. They are hard to find the right spot to seat. I can see him missing the spot and thinking that they are down.

 

[Brett Hansen CDT]

Straumann is the only implant where I have experienced this. They use plastic snap caps on their closed tray impressions. Sometimes you really have to press hard to get the impression coping to seat. I think sometimes that cap might also become dislodged in the impression. I am just very careful when I get these impressions in and I have told some doctors, that have asked, that it is fine not to use the impression cap to avoid this issue.

 

[rkm rdt]

I bought a Trios to avoid this since 2014.

 

[Pronto]

So I figure I'd do a follow up on this case. We repoured the original impression. Both models were extremely close. I made an appointment and went over what we had found. Dr decided to take a new impression after trying in the abutments again. We poured it up and found abutment #14 was in indeed very high. Surprisingly #15 was spot in. So something happend to the original impression on #14. I was able to rescue the #14 abutment with a double cast. Things are looking like a go now. Good to find out it wasn't us. Dr took it well. He's not a fan of the closed tray and this just reinforced that.