Anonymous
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Anonymous
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So what you are saing is that micro-threads do not stop bone loss?
The micro threads where originally provided to allow for adequate wall thickness for a deep conical design. The ideal outer diameter or radius of the threads was determined by finite element analysis. See Journal of Biomechanics 2003 (1247-1258) and US patent number 6,036,491 if you are really interested.
I don't mean to imply that ideally shaped/profiled micro threads don't play a role in crestal bone maintenance, but the upward and outward facing reverse bevel at the top of Astra implants may have a stabilizing effect on the CT fibers as the bottom of the implant gingival complex and this may have a significant role in crestal bone maintenance. This is only a hypothesis on my part but look at the one thing in common with Astra, Ankylos, Bicon and NobelActive which all share a deep conical design and have a platform switch to some degree and not all having micro or mini threads. Now compare their results to what seems to be happening around ScrewPlants without a platform switch but a design that includes mini threads, a stable platform and blasting to the top of the fixture..................... and it does make you wonder.
There are a combination of factors that come into play and it isn't easy to determine which design element is more important than another. Certainly you want a stable interface if you have the choice. Does a platform switch work for the reason I’m suggesting and not the biologic width nonsense some suggest? Admittedly it is hard to say. Therefore the only thing you can rely on as a clinician is long term data from a specific design and make your choice(s) accordingly.