Why do you always have to grind and adjust new restorations to get them seated?
It’s frustrating for sure. It feels like you have been betrayed by your lab. It feels like your lab does not care about you. It is embarrassing to grind on a beautiful new crown in front of your patient. The more you grind the more you imagine your patient refusing to have that put in their mouth. The longer this goes on the more you think about calling your lab and complaining. Maybe you are thinking of changing labs for certain things.
What do the high end laboratories do to make their crowns so “seat friendly”? Why doesn’t someone in your lab go get trained in having crowns seat easily?
What’s my secret?
It’s not just one thing. It is many techniques, systems, employees, coming together as a high functioning team. It is happy employees with great attitudes, working towards a game they can win.
Here is a couple of easy techniques for the lab that will make your life so much easier.
1- Mix stone according to manufacturers specs (not the way your model man has done it forever)
2- Let the stone set and harden for the recommended time. Pin and section.
3- Assuming you did the same for the opposing, articulate the case correctly.
4- Equilibrate the occlusion over the whole case with marking silk and a #8 round bur. Remove any junk or bubbles, then tap lightly with the articulating tape and softly grind the stone where it marks on the working model. Continue until the case is equilibrated and the occlusion looks socked in. Do not over grind. Use common sense and adjust until the bite looks natural and most all of the teeth are occluding.
5- Seal all of the occlusal surfaces on upper and lower.
6- Pour working model 2 more times. Once for solid model adjacent contacts. Once to check solid model accuracy. Overkill? Not on your life!
7- Fabricate the restoration as normal.
8- Tap and adjust the crown out of occlusion. Remove the stone sections and tap on the crown only. Adjust each of those marks on the crown. Repeat.
9- Seat the crown carefully on a solid model. Do not force down or abrade the adjacent contacts. Mark and adjust slightly each distal and mesial contact. Take your time as the crown seats. Only adjust where the red marks are, also adjusting the inside where it abraids on the stone. When the margins are fully seated and the contacts are broad, change to the 2nd solid model.
10- This is surprising for most technicians as they find that they did indeed abraid the stone on the 1st solid model and the crown needs further adjusting to fit onto the the 2nd solid model.
This new technique will take some practice and repetition to master. The only excuse for not following this technique for every case, is if you did not provide an impression that can be repoured, or a digital case.
This comes from almost 40 years of watching chair side while my work gets seated. Trust me! Technicians start this technique today. Dentists, have your lab read this and follow exactly. I promise you will both be very happy with the chair side time cut to nothing. And your patients will love you for it.
I sincerely hope this helps.