Hi Carlos
What we are seeing more of are cases being impressed at the fixture level with hopes to not have to use MUA's. I disagree with this restorative path as its exceedingly easier when the proper abutments are in place to bring the restorative platform up to gingival height. The problem or necessity to this path is generally due to lack of surgical planning for the intended restorative path.
Some of the reasons I see this happening is:
1) Patient is wearing a conventional denture and the client does not want to deal with MUA's in the way until the transitioned appliance or BETA of the hybrid is ready.
2) Dr does not want to be responsible for ordering the proper cuff heights of the abutments
3) Dr is trying to see if he can save the money and not use MUA's
If the case is an immediate load case, (transitioned imd denture) most times the surgeon is doing his job and placing the MUA's and the path is set, HOWEVER if they are just going to uncover after integration the path is less clear.
So here is the challenge we are ready for final imp, no MUA's are in place , We are now taking a fixture level impression with the POSSIBILITY of adding abutments we need to know where the internal engaging element are no mater what. This means we need to use engaging parts. Nobel makes some short engaging impression copings to help release when we need to go this route but when joining these together in the mouth with an open tray impression its very hard to get the case to release. SO i prefer when we have our master model poured we will need to now determine if we will be adding abutments to the case. It's not always easy to know the angulation without having our diagnostic done or at least scanned into the computer which makes it even more complicated. Now you see why I frown upon this path.
To complicate things even more I have had some clients order Nobels NON ENG ANGLE MUA's oh what a headache these are. Its one of the worst products I have ever seen hit this market. It was created to be a band aid for poor surgical work especially when used in conjunction with the nobel REPLACE fixtures.
So now the next topic comes up are we going to make our verification jig at the fixture level or at the abutment level?
If I am adding abutments to a fixture level impression I require a new impression at the abutment level. I will add my abutments to the models and use non eng temp cylinders that make a jig and then section it and make a custom tray over it. I then have the client join the jig in the mouth and make the master impression. After we pour this model up I section the custom tray to try and SAVE the joined jig. I clean the jig up and reinforce and this will be returned with a screw retained bite rim to get moving to the next step. Its at this step that the true validation of our master model is known. I request digital verification to come to my email before we move forward with the case.
Now it's pretty straightforward once you get here and it becomes so perfectly clear why surgical planning is so important for these cases.
So as I wrap up this novel I will just share there is a reason why the lab needs to take a bigger piece of the restorative pie.
My main reason for sharing is in hopes to help the younger techs looking to set their own protocols up. It's so important to have everyone on the team on the same page and not alter from a known successful path. Both YOU and your restoring client are married to these cases, don't let your clients inability to follow your path become a financial burden for you by allowing them to call the shots. I don't care how many initials they have behind their name or how many successful cases they have done "Their way" If they want to work with me I am strict on my path. Trust me I am not joking I have turned down huge dollar cases from new clients when they did not want to partner with me. I sleep much better doing it the right way.
John thank you for taking the time to write down your thoughts on the matter.. I agree with you in a lot of your points, I wish more surgeons/GPs placing would at least plan their placement even if don't go guided..
When doing a fixture level jig for some of my cases I use engaging Ti cylinders and MUA's selectively on implants severely tilted, but it's critical that I index the cuff of the MUA and modify the engaging features of the cylinders for a quick release of the jig while keeping it engaging; I split the jig for two separate pieces if needed. Custom tray is always included. The new model should definitely be more accurate and the reason behind all this.
I then proceed to do whatever I need to do (not necessarily including MUA in the final treatment).. By throwing a MUA or two and modifying the other cylinders I'm making for easier "release" of the open tray., -- Indexed MUA's can be sterilized and reused for future jigs though..
For indexing the MUA's I make three notches on the elbow region of the MUA helping me re-align all pieces before pouring models., this is when implants are not too deep and the elbow region of the MUA is equal-gingival to supra.. in a a deeper implant situation then I may suggest keeping the MUA in mouth and a whole different treatment plans develops..
I'll snap a picture on my next one see what you think..
Take care John..
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