i need some information about the lego technique because i´m searching about differents materials and i dont have many results :)
this one “A chair side cast with removable die for the fabrication of indirect composite resin restorations.”
Save your time to research this technique. It was researched already 30 years ago by several companies. It has not been successful for several reasons.
You must use a combination of polyether for the impression and silicone for the impression, otherwise the materials could polymerize together.
If you use a silicone, with high hardness/high elastic modulus for the impression, you have problems with the fine margin details or thin cavity walls. The silicone just does not flow as easily into the fine structures as you would like it. If you push it into the polyether impression with increased pressure, you are very likely to cause distortion of the impression.
On the other hand, if you do not use a hard silicone, you will not be able to model a composite with normal viscosity. Especially not if you have a large cavity that leaves only thin tooth structures around the cavity.
All in all, it was a waste of my life to bother with this technique, even though I tried hard to get a good result. Save yourself the trouble. It is not worth it.
The Lego piece is just a detail of less importance considering all the other problems of this technique. And please do not forget, it is no alternative to modify the clinical cavity configuration to make the cavity better fit to this chairside cast technique. Only the cavity outline should dictate the design of the preparation, not the limits of any manufacturing technique.
Sincerely
Karl-Heinz
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Karl-Heinz Kunzelmann thanks for answer, do you have any article to prove, only for student reason, i would love learn more about the subject and an another question what restaurative option would you preffer in this cases?
There are some publications in German. Mostly grey literature. Like reports to the companies. I do not think that you will find too many references in English. The companies who investigated this technique were Vivadent, Coltene, Kulzer, Espe and some 20 years later Voco (see "Grandioso inlay system"). It was never a success therefore this idea just vanished.
Can you specify what you mean by "this cases"?
Sincerely
Karl-Heinz
Karl-Heinz Kunzelmann
in indirect restoration, witch a certain amount of tooth loss (enamel and dentine) I was looking for alternatives ways to the labotarory inlay, onlays or overlays or only work with a good composite resin ?
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