3 shape Splint/Night guard occlusion problem

[Jin ahn]

Hi, I've been using 3 shape for designing splints for few months, and pretty satisfied with the result. However, I always encounter one problem with the printed splint. (By the way, I'm using Asiga max as 3d printer, and using keysoft resin.)

I always test the printed splint with the mounted models for testing right retention, bite marks, and any minor issues.

The problem is that the most splints do not have all bite marks that was shown on 3 shape splint studio. Whenever I put splint on the model and test with antagonist model, I always get few bite marks around second molar and no bite mark for other teeth. Therefore, I always have to grind off that area to get other teeth's bite marks.

What I found is that antagonist cusp tips are not sitting on exact area that I designed (it's pretty obvious to figure out since the printed splints have visible paved bite marks from the beginning),and touching few mm away from the desired area. I always do mounting and articulating carefully while designing, but still this kind of problem keep happening. I wonder if anybody having similar problem.

 

[Marcus Dods]

The digital process for the NG is far from perfect. You will find often the discrepancy that arises is not necessarily due to the design or the printer although both steps could be involved. The curing step is often overlooked. Are you curing the splint with the supports or do you remove supports first. It is possible the curing step (the most likely culprit here) us what is causing your issues. It was advised to our lab to remove the supports after curing to reduce chances of warping. Even a small amount of warping can move your contacts from the designed spot. When this does occur the adjustments you described where necessary to restore the other contact points. We did however notice that the the adjustments was reduced by changing to curing with supports but did not eliminate the need for final adjustments completely. More so we realized that the adjustment step had to become an accepted part of the workflow.

i hope this helps, although i doubt that it provides the whole answer that you were seeking.
kind regards

 

[Brett Hansen CDT]

I have designed 3 Keysplint NGs on 3Shape and printed them in our Asiga 4K. The first two I made for my sister and her husband and the third one is for me. I followed very closely the design video from Zahn on Youtube. I don't have any experience with NG design prior to making these three. When I showed my lab owner the first NG, he noticed the same thing you brought up...not all the opposing teeth were in occlusion with the splint. I think(keep in mind my very limited experience) that these are supposed to be in what we would call centric occlusion all the way around the arch. When I adjust the design for excursive movements, the software takes the splint out of occlusion in some areas. My sister and her husband have been very happy with their NGs. For me, I find it to be very comfortable as well. Especially when my lower jaw moves in excursives. I have looked around for some better technical information on splint design and haven't had much luck. I am kind of trusting the software and the videos I have watched but I would really like to know more about the "whys" of splint design.

 

[Marcus Dods]

if you have achieved a comfortable fit then you are definitely using the right methods. The big tell for me was the following morning. It was easy to tell if the design had issues that affected teeth movement and thus discomfort. There are many good tutorial videos on youtube, some are very basic where others do provide more explanation for each step.
There are many varieties of NG. Designing a good NG starts with understanding what it is intended for. What treatment protocol was the dentist intending. This purpose of the NG will reflect in the design.
Knowing what type of design to focus on for the case helps. Then you can balance function and comfort by adjusting shape, insertion, controlling guidance.
One of the biggest design tips i learnt was the need to make small adjustments and to reset stops afterwards every time. The smallest change can alter contacts and change the whole function of the NG.
My recommendation to you at this stage would be to go through several of the 3shape tutorials for different NG design types. They often explain the why of the step. Turn on Closed captions so you don't miss these explanations as they often coincide with the actual step being done. How to increase or decrease retention and why...How to control and shape guidance .... but always keep in mind your end goal so the function of the NG isnt lost.
The majority of NG we do are very simple and dont focus on guidance. And in discussions with several dentists was shocked that they often where unaware of how many types of NG there were.
If you are looking to understand the Whys i would start there. Search for Ng types and and there related desired function. It will help tremendously in understanding the design itself.

 

[ztech]

Hi, I've been using 3 shape for designing splints for few months, and pretty satisfied with the result. However, I always encounter one problem with the printed splint. (By the way, I'm using Asiga max as 3d printer, and using keysoft resin.)

I always test the printed splint with the mounted models for testing right retention, bite marks, and any minor issues.

The problem is that the most splints do not have all bite marks that was shown on 3 shape splint studio. Whenever I put splint on the model and test with antagonist model, I always get few bite marks around second molar and no bite mark for other teeth. Therefore, I always have to grind off that area to get other teeth's bite marks.

What I found is that antagonist cusp tips are not sitting on exact area that I designed (it's pretty obvious to figure out since the printed splints have visible paved bite marks from the beginning),and touching few mm away from the desired area. I always do mounting and articulating carefully while designing, but still this kind of problem keep happening. I wonder if anybody having similar problem

If you have a premature contact in the posterior it is likely an arc of closure error when you digitally opened the splint. To simply decrease this error, scan the models at the desired opening and you should get centric as designed. This will leave an excursive error but that can be managed by paying close attention to ant/post position when setting the models up in the digital articulator. Link below gives a fairly concise explanation of the problem.

https://www.panadent.com/1Articulator_Selection_for_Restorative_Den..pdf

 

[Marcus Dods]

ztech has a valid point, which i omitted as a possibility based on you saying that you did the mounting step with great care. However, it might be something to rule out as well.

 

[Jin ahn]

If you have a premature contact in the posterior it is likely an arc of closure error when you digitally opened the splint. To simply decrease this error, scan the models at the desired opening and you should get centric as designed. This will leave an excursive error but that can be managed by paying close attention to ant/post position when setting the models up in the digital articulator. Link below gives a fairly concise explanation of the problem.

https://www.panadent.com/1Articulator_Selection_for_Restorative_Den..pdf

I wonder how you scan the model with opened state.

 

[Jin ahn]

I wonder how you scan the model with opened state.

Since we're using 3 shape scanner for scanning the stone model, I can't put the articulated models in opened state unless I put the whole articulator in the scanner, but it will be too heavy for the magnetic plate to hold it.

 

[Marcus Dods]

depending on the scanner, 3shape has a special pad that lays on the magnetic plate, and is used to scan cases with the articulator. If you search youtube for 3shape and articulator holder you should be able to see a demo.
regards

 

[ztech]

Since we're using 3 shape scanner for scanning the stone model, I can't put the articulated models in opened state unless I put the whole articulator in the scanner, but it will be too heavy for the magnetic plate to hold it.

I am not familiar with 3shape scanners, so I am of no use there. As far as how I do it. I can scan a full articulator in my DOF HD but that is only useful with an articulator that has been mounted with a facebow. When I did them they came with a bite that had been made by the provider at an open position. They use a leaf gauge and open to desired thickness then use blue mouse or any other bite registration material and make a thick bite at that opening. I take the bite and orient the models together using that and lute them to that position and that is what I design the flat plane guards to. I then mount using the bite and adjust centric.

 

[Jin ahn]

depending on the scanner, 3shape has a special pad that lays on the magnetic plate, and is used to scan cases with the articulator. If you search youtube for 3shape and articulator holder you should be able to see a demo.
regards

Unfortunately, my scanner does not have that function (model D700). Shoot, this stuff gives me so much stress.

 

[Marcus Dods]

you might want to consider upgrading if you want to pursue more digital process. Good news is 3shape give a fair trade in value for the older scanners,
My friends lab got between 2-3 thousand when upgrading his scanner.
but first i would try to source someone local that has a scanner than you could test a case to see if it helps with your original issue.

 

[Brett Hansen CDT]

Unfortunately, my scanner does not have that function (model D700). Shoot, this stuff gives me so much stress.

I think our first 3shape scanner was a D800. We upgraded to the E3 a few years ago. Huge upgrade! Much faster and you get the ability to scan anatomical articulators easily. As Marcus said, you will get a fair trade in value for your D700

 

[nellis8]

Hi. I am new to this group. I purchased a 3Shape D800 Scanner last year. I purchased from a lab that went out of business and I got it new in box. We set it up and did some tests ( Came out amazing) but we have decided to go a different route and want to sell the D800. Has about 3 or 4 hours of actual scanning time. Do you know what I can expect to get for it based on that and where would I list a scanner like this?

 

[nellis8]

Is there a thread here that I can ask questions on specific scanners and try to figure out which scanner is the right one for my Dental Lab format?
Sorry if this is considered rude to jump in on another conversation but I saw you had owned a D800. Thanks _Neil_

 

[rkm rdt]

Is there a thread here that I can ask questions on specific scanners and try to figure out which scanner is the right one for my Dental Lab format?
Sorry if this is considered rude to jump in on another conversation but I saw you had owned a D800. Thanks _Neil_

You can ask any questions on any thread.
We consider hijacking as a method of keeping the thread open until an intelligent response is submitted.